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Diffstat (limited to 'lib/maple_tree.c')
| -rw-r--r-- | lib/maple_tree.c | 7564 |
1 files changed, 7564 insertions, 0 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c new file mode 100644 index 000000000000..6f241bb38799 --- /dev/null +++ b/lib/maple_tree.c @@ -0,0 +1,7564 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Maple Tree implementation + * Copyright (c) 2018-2022 Oracle Corporation + * Authors: Liam R. Howlett <Liam.Howlett@oracle.com> + * Matthew Wilcox <willy@infradead.org> + * Copyright (c) 2023 ByteDance + * Author: Peng Zhang <zhangpeng.00@bytedance.com> + */ + +/* + * DOC: Interesting implementation details of the Maple Tree + * + * Each node type has a number of slots for entries and a number of slots for + * pivots. In the case of dense nodes, the pivots are implied by the position + * and are simply the slot index + the minimum of the node. + * + * In regular B-Tree terms, pivots are called keys. The term pivot is used to + * indicate that the tree is specifying ranges. Pivots may appear in the + * subtree with an entry attached to the value whereas keys are unique to a + * specific position of a B-tree. Pivot values are inclusive of the slot with + * the same index. + * + * + * The following illustrates the layout of a range64 nodes slots and pivots. + * + * + * Slots -> | 0 | 1 | 2 | ... | 12 | 13 | 14 | 15 | + * ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬ + * │ │ │ │ │ │ │ │ └─ Implied maximum + * │ │ │ │ │ │ │ └─ Pivot 14 + * │ │ │ │ │ │ └─ Pivot 13 + * │ │ │ │ │ └─ Pivot 12 + * │ │ │ │ └─ Pivot 11 + * │ │ │ └─ Pivot 2 + * │ │ └─ Pivot 1 + * │ └─ Pivot 0 + * └─ Implied minimum + * + * Slot contents: + * Internal (non-leaf) nodes contain pointers to other nodes. + * Leaf nodes contain entries. + * + * The location of interest is often referred to as an offset. All offsets have + * a slot, but the last offset has an implied pivot from the node above (or + * UINT_MAX for the root node. + * + * Ranges complicate certain write activities. When modifying any of + * the B-tree variants, it is known that one entry will either be added or + * deleted. When modifying the Maple Tree, one store operation may overwrite + * the entire data set, or one half of the tree, or the middle half of the tree. + * + */ + + +#include <linux/maple_tree.h> +#include <linux/xarray.h> +#include <linux/types.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/limits.h> +#include <asm/barrier.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/maple_tree.h> + +#define MA_ROOT_PARENT 1 + +/* + * Maple state flags + * * MA_STATE_BULK - Bulk insert mode + * * MA_STATE_REBALANCE - Indicate a rebalance during bulk insert + * * MA_STATE_PREALLOC - Preallocated nodes, WARN_ON allocation + */ +#define MA_STATE_BULK 1 +#define MA_STATE_REBALANCE 2 +#define MA_STATE_PREALLOC 4 + +#define ma_parent_ptr(x) ((struct maple_pnode *)(x)) +#define mas_tree_parent(x) ((unsigned long)(x->tree) | MA_ROOT_PARENT) +#define ma_mnode_ptr(x) ((struct maple_node *)(x)) +#define ma_enode_ptr(x) ((struct maple_enode *)(x)) +static struct kmem_cache *maple_node_cache; + +#ifdef CONFIG_DEBUG_MAPLE_TREE +static const unsigned long mt_max[] = { + [maple_dense] = MAPLE_NODE_SLOTS, + [maple_leaf_64] = ULONG_MAX, + [maple_range_64] = ULONG_MAX, + [maple_arange_64] = ULONG_MAX, +}; +#define mt_node_max(x) mt_max[mte_node_type(x)] +#endif + +static const unsigned char mt_slots[] = { + [maple_dense] = MAPLE_NODE_SLOTS, + [maple_leaf_64] = MAPLE_RANGE64_SLOTS, + [maple_range_64] = MAPLE_RANGE64_SLOTS, + [maple_arange_64] = MAPLE_ARANGE64_SLOTS, +}; +#define mt_slot_count(x) mt_slots[mte_node_type(x)] + +static const unsigned char mt_pivots[] = { + [maple_dense] = 0, + [maple_leaf_64] = MAPLE_RANGE64_SLOTS - 1, + [maple_range_64] = MAPLE_RANGE64_SLOTS - 1, + [maple_arange_64] = MAPLE_ARANGE64_SLOTS - 1, +}; +#define mt_pivot_count(x) mt_pivots[mte_node_type(x)] + +static const unsigned char mt_min_slots[] = { + [maple_dense] = MAPLE_NODE_SLOTS / 2, + [maple_leaf_64] = (MAPLE_RANGE64_SLOTS / 2) - 2, + [maple_range_64] = (MAPLE_RANGE64_SLOTS / 2) - 2, + [maple_arange_64] = (MAPLE_ARANGE64_SLOTS / 2) - 1, +}; +#define mt_min_slot_count(x) mt_min_slots[mte_node_type(x)] + +#define MAPLE_BIG_NODE_SLOTS (MAPLE_RANGE64_SLOTS * 2 + 2) +#define MAPLE_BIG_NODE_GAPS (MAPLE_ARANGE64_SLOTS * 2 + 1) + +struct maple_big_node { + struct maple_pnode *parent; + unsigned long pivot[MAPLE_BIG_NODE_SLOTS - 1]; + union { + struct maple_enode *slot[MAPLE_BIG_NODE_SLOTS]; + struct { + unsigned long padding[MAPLE_BIG_NODE_GAPS]; + unsigned long gap[MAPLE_BIG_NODE_GAPS]; + }; + }; + unsigned char b_end; + enum maple_type type; +}; + +/* + * The maple_subtree_state is used to build a tree to replace a segment of an + * existing tree in a more atomic way. Any walkers of the older tree will hit a + * dead node and restart on updates. + */ +struct maple_subtree_state { + struct ma_state *orig_l; /* Original left side of subtree */ + struct ma_state *orig_r; /* Original right side of subtree */ + struct ma_state *l; /* New left side of subtree */ + struct ma_state *m; /* New middle of subtree (rare) */ + struct ma_state *r; /* New right side of subtree */ + struct ma_topiary *free; /* nodes to be freed */ + struct ma_topiary *destroy; /* Nodes to be destroyed (walked and freed) */ + struct maple_big_node *bn; +}; + +#ifdef CONFIG_KASAN_STACK +/* Prevent mas_wr_bnode() from exceeding the stack frame limit */ +#define noinline_for_kasan noinline_for_stack +#else +#define noinline_for_kasan inline +#endif + +/* Functions */ +static inline struct maple_node *mt_alloc_one(gfp_t gfp) +{ + return kmem_cache_alloc(maple_node_cache, gfp); +} + +static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes) +{ + return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes); +} + +static inline void mt_free_one(struct maple_node *node) +{ + kmem_cache_free(maple_node_cache, node); +} + +static inline void mt_free_bulk(size_t size, void __rcu **nodes) +{ + kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes); +} + +static void mt_free_rcu(struct rcu_head *head) +{ + struct maple_node *node = container_of(head, struct maple_node, rcu); + + kmem_cache_free(maple_node_cache, node); +} + +/* + * ma_free_rcu() - Use rcu callback to free a maple node + * @node: The node to free + * + * The maple tree uses the parent pointer to indicate this node is no longer in + * use and will be freed. + */ +static void ma_free_rcu(struct maple_node *node) +{ + WARN_ON(node->parent != ma_parent_ptr(node)); + call_rcu(&node->rcu, mt_free_rcu); +} + +static void mas_set_height(struct ma_state *mas) +{ + unsigned int new_flags = mas->tree->ma_flags; + + new_flags &= ~MT_FLAGS_HEIGHT_MASK; + MAS_BUG_ON(mas, mas->depth > MAPLE_HEIGHT_MAX); + new_flags |= mas->depth << MT_FLAGS_HEIGHT_OFFSET; + mas->tree->ma_flags = new_flags; +} + +static unsigned int mas_mt_height(struct ma_state *mas) +{ + return mt_height(mas->tree); +} + +static inline unsigned int mt_attr(struct maple_tree *mt) +{ + return mt->ma_flags & ~MT_FLAGS_HEIGHT_MASK; +} + +static __always_inline enum maple_type mte_node_type( + const struct maple_enode *entry) +{ + return ((unsigned long)entry >> MAPLE_NODE_TYPE_SHIFT) & + MAPLE_NODE_TYPE_MASK; +} + +static __always_inline bool ma_is_dense(const enum maple_type type) +{ + return type < maple_leaf_64; +} + +static __always_inline bool ma_is_leaf(const enum maple_type type) +{ + return type < maple_range_64; +} + +static __always_inline bool mte_is_leaf(const struct maple_enode *entry) +{ + return ma_is_leaf(mte_node_type(entry)); +} + +/* + * We also reserve values with the bottom two bits set to '10' which are + * below 4096 + */ +static __always_inline bool mt_is_reserved(const void *entry) +{ + return ((unsigned long)entry < MAPLE_RESERVED_RANGE) && + xa_is_internal(entry); +} + +static __always_inline void mas_set_err(struct ma_state *mas, long err) +{ + mas->node = MA_ERROR(err); + mas->status = ma_error; +} + +static __always_inline bool mas_is_ptr(const struct ma_state *mas) +{ + return mas->status == ma_root; +} + +static __always_inline bool mas_is_start(const struct ma_state *mas) +{ + return mas->status == ma_start; +} + +static __always_inline bool mas_is_none(const struct ma_state *mas) +{ + return mas->status == ma_none; +} + +static __always_inline bool mas_is_paused(const struct ma_state *mas) +{ + return mas->status == ma_pause; +} + +static __always_inline bool mas_is_overflow(struct ma_state *mas) +{ + return mas->status == ma_overflow; +} + +static inline bool mas_is_underflow(struct ma_state *mas) +{ + return mas->status == ma_underflow; +} + +static __always_inline struct maple_node *mte_to_node( + const struct maple_enode *entry) +{ + return (struct maple_node *)((unsigned long)entry & ~MAPLE_NODE_MASK); +} + +/* + * mte_to_mat() - Convert a maple encoded node to a maple topiary node. + * @entry: The maple encoded node + * + * Return: a maple topiary pointer + */ +static inline struct maple_topiary *mte_to_mat(const struct maple_enode *entry) +{ + return (struct maple_topiary *) + ((unsigned long)entry & ~MAPLE_NODE_MASK); +} + +/* + * mas_mn() - Get the maple state node. + * @mas: The maple state + * + * Return: the maple node (not encoded - bare pointer). + */ +static inline struct maple_node *mas_mn(const struct ma_state *mas) +{ + return mte_to_node(mas->node); +} + +/* + * mte_set_node_dead() - Set a maple encoded node as dead. + * @mn: The maple encoded node. + */ +static inline void mte_set_node_dead(struct maple_enode *mn) +{ + mte_to_node(mn)->parent = ma_parent_ptr(mte_to_node(mn)); + smp_wmb(); /* Needed for RCU */ +} + +/* Bit 1 indicates the root is a node */ +#define MAPLE_ROOT_NODE 0x02 +/* maple_type stored bit 3-6 */ +#define MAPLE_ENODE_TYPE_SHIFT 0x03 +/* Bit 2 means a NULL somewhere below */ +#define MAPLE_ENODE_NULL 0x04 + +static inline struct maple_enode *mt_mk_node(const struct maple_node *node, + enum maple_type type) +{ + return (void *)((unsigned long)node | + (type << MAPLE_ENODE_TYPE_SHIFT) | MAPLE_ENODE_NULL); +} + +static inline void *mte_mk_root(const struct maple_enode *node) +{ + return (void *)((unsigned long)node | MAPLE_ROOT_NODE); +} + +static inline void *mte_safe_root(const struct maple_enode *node) +{ + return (void *)((unsigned long)node & ~MAPLE_ROOT_NODE); +} + +static inline void *mte_set_full(const struct maple_enode *node) +{ + return (void *)((unsigned long)node & ~MAPLE_ENODE_NULL); +} + +static inline void *mte_clear_full(const struct maple_enode *node) +{ + return (void *)((unsigned long)node | MAPLE_ENODE_NULL); +} + +static inline bool mte_has_null(const struct maple_enode *node) +{ + return (unsigned long)node & MAPLE_ENODE_NULL; +} + +static __always_inline bool ma_is_root(struct maple_node *node) +{ + return ((unsigned long)node->parent & MA_ROOT_PARENT); +} + +static __always_inline bool mte_is_root(const struct maple_enode *node) +{ + return ma_is_root(mte_to_node(node)); +} + +static inline bool mas_is_root_limits(const struct ma_state *mas) +{ + return !mas->min && mas->max == ULONG_MAX; +} + +static __always_inline bool mt_is_alloc(struct maple_tree *mt) +{ + return (mt->ma_flags & MT_FLAGS_ALLOC_RANGE); +} + +/* + * The Parent Pointer + * Excluding root, the parent pointer is 256B aligned like all other tree nodes. + * When storing a 32 or 64 bit values, the offset can fit into 5 bits. The 16 + * bit values need an extra bit to store the offset. This extra bit comes from + * a reuse of the last bit in the node type. This is possible by using bit 1 to + * indicate if bit 2 is part of the type or the slot. + * + * Note types: + * 0x??1 = Root + * 0x?00 = 16 bit nodes + * 0x010 = 32 bit nodes + * 0x110 = 64 bit nodes + * + * Slot size and alignment + * 0b??1 : Root + * 0b?00 : 16 bit values, type in 0-1, slot in 2-7 + * 0b010 : 32 bit values, type in 0-2, slot in 3-7 + * 0b110 : 64 bit values, type in 0-2, slot in 3-7 + */ + +#define MAPLE_PARENT_ROOT 0x01 + +#define MAPLE_PARENT_SLOT_SHIFT 0x03 +#define MAPLE_PARENT_SLOT_MASK 0xF8 + +#define MAPLE_PARENT_16B_SLOT_SHIFT 0x02 +#define MAPLE_PARENT_16B_SLOT_MASK 0xFC + +#define MAPLE_PARENT_RANGE64 0x06 +#define MAPLE_PARENT_RANGE32 0x04 +#define MAPLE_PARENT_NOT_RANGE16 0x02 + +/* + * mte_parent_shift() - Get the parent shift for the slot storage. + * @parent: The parent pointer cast as an unsigned long + * Return: The shift into that pointer to the star to of the slot + */ +static inline unsigned long mte_parent_shift(unsigned long parent) +{ + /* Note bit 1 == 0 means 16B */ + if (likely(parent & MAPLE_PARENT_NOT_RANGE16)) + return MAPLE_PARENT_SLOT_SHIFT; + + return MAPLE_PARENT_16B_SLOT_SHIFT; +} + +/* + * mte_parent_slot_mask() - Get the slot mask for the parent. + * @parent: The parent pointer cast as an unsigned long. + * Return: The slot mask for that parent. + */ +static inline unsigned long mte_parent_slot_mask(unsigned long parent) +{ + /* Note bit 1 == 0 means 16B */ + if (likely(parent & MAPLE_PARENT_NOT_RANGE16)) + return MAPLE_PARENT_SLOT_MASK; + + return MAPLE_PARENT_16B_SLOT_MASK; +} + +/* + * mas_parent_type() - Return the maple_type of the parent from the stored + * parent type. + * @mas: The maple state + * @enode: The maple_enode to extract the parent's enum + * Return: The node->parent maple_type + */ +static inline +enum maple_type mas_parent_type(struct ma_state *mas, struct maple_enode *enode) +{ + unsigned long p_type; + + p_type = (unsigned long)mte_to_node(enode)->parent; + if (WARN_ON(p_type & MAPLE_PARENT_ROOT)) + return 0; + + p_type &= MAPLE_NODE_MASK; + p_type &= ~mte_parent_slot_mask(p_type); + switch (p_type) { + case MAPLE_PARENT_RANGE64: /* or MAPLE_PARENT_ARANGE64 */ + if (mt_is_alloc(mas->tree)) + return maple_arange_64; + return maple_range_64; + } + + return 0; +} + +/* + * mas_set_parent() - Set the parent node and encode the slot + * @enode: The encoded maple node. + * @parent: The encoded maple node that is the parent of @enode. + * @slot: The slot that @enode resides in @parent. + * + * Slot number is encoded in the enode->parent bit 3-6 or 2-6, depending on the + * parent type. + */ +static inline +void mas_set_parent(struct ma_state *mas, struct maple_enode *enode, + const struct maple_enode *parent, unsigned char slot) +{ + unsigned long val = (unsigned long)parent; + unsigned long shift; + unsigned long type; + enum maple_type p_type = mte_node_type(parent); + + MAS_BUG_ON(mas, p_type == maple_dense); + MAS_BUG_ON(mas, p_type == maple_leaf_64); + + switch (p_type) { + case maple_range_64: + case maple_arange_64: + shift = MAPLE_PARENT_SLOT_SHIFT; + type = MAPLE_PARENT_RANGE64; + break; + default: + case maple_dense: + case maple_leaf_64: + shift = type = 0; + break; + } + + val &= ~MAPLE_NODE_MASK; /* Clear all node metadata in parent */ + val |= (slot << shift) | type; + mte_to_node(enode)->parent = ma_parent_ptr(val); +} + +/* + * mte_parent_slot() - get the parent slot of @enode. + * @enode: The encoded maple node. + * + * Return: The slot in the parent node where @enode resides. + */ +static __always_inline +unsigned int mte_parent_slot(const struct maple_enode *enode) +{ + unsigned long val = (unsigned long)mte_to_node(enode)->parent; + + if (unlikely(val & MA_ROOT_PARENT)) + return 0; + + /* + * Okay to use MAPLE_PARENT_16B_SLOT_MASK as the last bit will be lost + * by shift if the parent shift is MAPLE_PARENT_SLOT_SHIFT + */ + return (val & MAPLE_PARENT_16B_SLOT_MASK) >> mte_parent_shift(val); +} + +/* + * mte_parent() - Get the parent of @node. + * @node: The encoded maple node. + * + * Return: The parent maple node. + */ +static __always_inline +struct maple_node *mte_parent(const struct maple_enode *enode) +{ + return (void *)((unsigned long) + (mte_to_node(enode)->parent) & ~MAPLE_NODE_MASK); +} + +/* + * ma_dead_node() - check if the @enode is dead. + * @enode: The encoded maple node + * + * Return: true if dead, false otherwise. + */ +static __always_inline bool ma_dead_node(const struct maple_node *node) +{ + struct maple_node *parent; + + /* Do not reorder reads from the node prior to the parent check */ + smp_rmb(); + parent = (void *)((unsigned long) node->parent & ~MAPLE_NODE_MASK); + return (parent == node); +} + +/* + * mte_dead_node() - check if the @enode is dead. + * @enode: The encoded maple node + * + * Return: true if dead, false otherwise. + */ +static __always_inline bool mte_dead_node(const struct maple_enode *enode) +{ + struct maple_node *parent, *node; + + node = mte_to_node(enode); + /* Do not reorder reads from the node prior to the parent check */ + smp_rmb(); + parent = mte_parent(enode); + return (parent == node); +} + +/* + * mas_allocated() - Get the number of nodes allocated in a maple state. + * @mas: The maple state + * + * The ma_state alloc member is overloaded to hold a pointer to the first + * allocated node or to the number of requested nodes to allocate. If bit 0 is + * set, then the alloc contains the number of requested nodes. If there is an + * allocated node, then the total allocated nodes is in that node. + * + * Return: The total number of nodes allocated + */ +static inline unsigned long mas_allocated(const struct ma_state *mas) +{ + if (!mas->alloc || ((unsigned long)mas->alloc & 0x1)) + return 0; + + return mas->alloc->total; +} + +/* + * mas_set_alloc_req() - Set the requested number of allocations. + * @mas: the maple state + * @count: the number of allocations. + * + * The requested number of allocations is either in the first allocated node, + * located in @mas->alloc->request_count, or directly in @mas->alloc if there is + * no allocated node. Set the request either in the node or do the necessary + * encoding to store in @mas->alloc directly. + */ +static inline void mas_set_alloc_req(struct ma_state *mas, unsigned long count) +{ + if (!mas->alloc || ((unsigned long)mas->alloc & 0x1)) { + if (!count) + mas->alloc = NULL; + else + mas->alloc = (struct maple_alloc *)(((count) << 1U) | 1U); + return; + } + + mas->alloc->request_count = count; +} + +/* + * mas_alloc_req() - get the requested number of allocations. + * @mas: The maple state + * + * The alloc count is either stored directly in @mas, or in + * @mas->alloc->request_count if there is at least one node allocated. Decode + * the request count if it's stored directly in @mas->alloc. + * + * Return: The allocation request count. + */ +static inline unsigned int mas_alloc_req(const struct ma_state *mas) +{ + if ((unsigned long)mas->alloc & 0x1) + return (unsigned long)(mas->alloc) >> 1; + else if (mas->alloc) + return mas->alloc->request_count; + return 0; +} + +/* + * ma_pivots() - Get a pointer to the maple node pivots. + * @node - the maple node + * @type - the node type + * + * In the event of a dead node, this array may be %NULL + * + * Return: A pointer to the maple node pivots + */ +static inline unsigned long *ma_pivots(struct maple_node *node, + enum maple_type type) +{ + switch (type) { + case maple_arange_64: + return node->ma64.pivot; + case maple_range_64: + case maple_leaf_64: + return node->mr64.pivot; + case maple_dense: + return NULL; + } + return NULL; +} + +/* + * ma_gaps() - Get a pointer to the maple node gaps. + * @node - the maple node + * @type - the node type + * + * Return: A pointer to the maple node gaps + */ +static inline unsigned long *ma_gaps(struct maple_node *node, + enum maple_type type) +{ + switch (type) { + case maple_arange_64: + return node->ma64.gap; + case maple_range_64: + case maple_leaf_64: + case maple_dense: + return NULL; + } + return NULL; +} + +/* + * mas_safe_pivot() - get the pivot at @piv or mas->max. + * @mas: The maple state + * @pivots: The pointer to the maple node pivots + * @piv: The pivot to fetch + * @type: The maple node type + * + * Return: The pivot at @piv within the limit of the @pivots array, @mas->max + * otherwise. + */ +static __always_inline unsigned long +mas_safe_pivot(const struct ma_state *mas, unsigned long *pivots, + unsigned char piv, enum maple_type type) +{ + if (piv >= mt_pivots[type]) + return mas->max; + + return pivots[piv]; +} + +/* + * mas_safe_min() - Return the minimum for a given offset. + * @mas: The maple state + * @pivots: The pointer to the maple node pivots + * @offset: The offset into the pivot array + * + * Return: The minimum range value that is contained in @offset. + */ +static inline unsigned long +mas_safe_min(struct ma_state *mas, unsigned long *pivots, unsigned char offset) +{ + if (likely(offset)) + return pivots[offset - 1] + 1; + + return mas->min; +} + +/* + * mte_set_pivot() - Set a pivot to a value in an encoded maple node. + * @mn: The encoded maple node + * @piv: The pivot offset + * @val: The value of the pivot + */ +static inline void mte_set_pivot(struct maple_enode *mn, unsigned char piv, + unsigned long val) +{ + struct maple_node *node = mte_to_node(mn); + enum maple_type type = mte_node_type(mn); + + BUG_ON(piv >= mt_pivots[type]); + switch (type) { + case maple_range_64: + case maple_leaf_64: + node->mr64.pivot[piv] = val; + break; + case maple_arange_64: + node->ma64.pivot[piv] = val; + break; + case maple_dense: + break; + } + +} + +/* + * ma_slots() - Get a pointer to the maple node slots. + * @mn: The maple node + * @mt: The maple node type + * + * Return: A pointer to the maple node slots + */ +static inline void __rcu **ma_slots(struct maple_node *mn, enum maple_type mt) +{ + switch (mt) { + case maple_arange_64: + return mn->ma64.slot; + case maple_range_64: + case maple_leaf_64: + return mn->mr64.slot; + case maple_dense: + return mn->slot; + } + + return NULL; +} + +static inline bool mt_write_locked(const struct maple_tree *mt) +{ + return mt_external_lock(mt) ? mt_write_lock_is_held(mt) : + lockdep_is_held(&mt->ma_lock); +} + +static __always_inline bool mt_locked(const struct maple_tree *mt) +{ + return mt_external_lock(mt) ? mt_lock_is_held(mt) : + lockdep_is_held(&mt->ma_lock); +} + +static __always_inline void *mt_slot(const struct maple_tree *mt, + void __rcu **slots, unsigned char offset) +{ + return rcu_dereference_check(slots[offset], mt_locked(mt)); +} + +static __always_inline void *mt_slot_locked(struct maple_tree *mt, + void __rcu **slots, unsigned char offset) +{ + return rcu_dereference_protected(slots[offset], mt_write_locked(mt)); +} +/* + * mas_slot_locked() - Get the slot value when holding the maple tree lock. + * @mas: The maple state + * @slots: The pointer to the slots + * @offset: The offset into the slots array to fetch + * + * Return: The entry stored in @slots at the @offset. + */ +static __always_inline void *mas_slot_locked(struct ma_state *mas, + void __rcu **slots, unsigned char offset) +{ + return mt_slot_locked(mas->tree, slots, offset); +} + +/* + * mas_slot() - Get the slot value when not holding the maple tree lock. + * @mas: The maple state + * @slots: The pointer to the slots + * @offset: The offset into the slots array to fetch + * + * Return: The entry stored in @slots at the @offset + */ +static __always_inline void *mas_slot(struct ma_state *mas, void __rcu **slots, + unsigned char offset) +{ + return mt_slot(mas->tree, slots, offset); +} + +/* + * mas_root() - Get the maple tree root. + * @mas: The maple state. + * + * Return: The pointer to the root of the tree + */ +static __always_inline void *mas_root(struct ma_state *mas) +{ + return rcu_dereference_check(mas->tree->ma_root, mt_locked(mas->tree)); +} + +static inline void *mt_root_locked(struct maple_tree *mt) +{ + return rcu_dereference_protected(mt->ma_root, mt_write_locked(mt)); +} + +/* + * mas_root_locked() - Get the maple tree root when holding the maple tree lock. + * @mas: The maple state. + * + * Return: The pointer to the root of the tree + */ +static inline void *mas_root_locked(struct ma_state *mas) +{ + return mt_root_locked(mas->tree); +} + +static inline struct maple_metadata *ma_meta(struct maple_node *mn, + enum maple_type mt) +{ + switch (mt) { + case maple_arange_64: + return &mn->ma64.meta; + default: + return &mn->mr64.meta; + } +} + +/* + * ma_set_meta() - Set the metadata information of a node. + * @mn: The maple node + * @mt: The maple node type + * @offset: The offset of the highest sub-gap in this node. + * @end: The end of the data in this node. + */ +static inline void ma_set_meta(struct maple_node *mn, enum maple_type mt, + unsigned char offset, unsigned char end) +{ + struct maple_metadata *meta = ma_meta(mn, mt); + + meta->gap = offset; + meta->end = end; +} + +/* + * mt_clear_meta() - clear the metadata information of a node, if it exists + * @mt: The maple tree + * @mn: The maple node + * @type: The maple node type + * @offset: The offset of the highest sub-gap in this node. + * @end: The end of the data in this node. + */ +static inline void mt_clear_meta(struct maple_tree *mt, struct maple_node *mn, + enum maple_type type) +{ + struct maple_metadata *meta; + unsigned long *pivots; + void __rcu **slots; + void *next; + + switch (type) { + case maple_range_64: + pivots = mn->mr64.pivot; + if (unlikely(pivots[MAPLE_RANGE64_SLOTS - 2])) { + slots = mn->mr64.slot; + next = mt_slot_locked(mt, slots, + MAPLE_RANGE64_SLOTS - 1); + if (unlikely((mte_to_node(next) && + mte_node_type(next)))) + return; /* no metadata, could be node */ + } + fallthrough; + case maple_arange_64: + meta = ma_meta(mn, type); + break; + default: + return; + } + + meta->gap = 0; + meta->end = 0; +} + +/* + * ma_meta_end() - Get the data end of a node from the metadata + * @mn: The maple node + * @mt: The maple node type + */ +static inline unsigned char ma_meta_end(struct maple_node *mn, + enum maple_type mt) +{ + struct maple_metadata *meta = ma_meta(mn, mt); + + return meta->end; +} + +/* + * ma_meta_gap() - Get the largest gap location of a node from the metadata + * @mn: The maple node + */ +static inline unsigned char ma_meta_gap(struct maple_node *mn) +{ + return mn->ma64.meta.gap; +} + +/* + * ma_set_meta_gap() - Set the largest gap location in a nodes metadata + * @mn: The maple node + * @mn: The maple node type + * @offset: The location of the largest gap. + */ +static inline void ma_set_meta_gap(struct maple_node *mn, enum maple_type mt, + unsigned char offset) +{ + + struct maple_metadata *meta = ma_meta(mn, mt); + + meta->gap = offset; +} + +/* + * mat_add() - Add a @dead_enode to the ma_topiary of a list of dead nodes. + * @mat - the ma_topiary, a linked list of dead nodes. + * @dead_enode - the node to be marked as dead and added to the tail of the list + * + * Add the @dead_enode to the linked list in @mat. + */ +static inline void mat_add(struct ma_topiary *mat, + struct maple_enode *dead_enode) +{ + mte_set_node_dead(dead_enode); + mte_to_mat(dead_enode)->next = NULL; + if (!mat->tail) { + mat->tail = mat->head = dead_enode; + return; + } + + mte_to_mat(mat->tail)->next = dead_enode; + mat->tail = dead_enode; +} + +static void mt_free_walk(struct rcu_head *head); +static void mt_destroy_walk(struct maple_enode *enode, struct maple_tree *mt, + bool free); +/* + * mas_mat_destroy() - Free all nodes and subtrees in a dead list. + * @mas - the maple state + * @mat - the ma_topiary linked list of dead nodes to free. + * + * Destroy walk a dead list. + */ +static void mas_mat_destroy(struct ma_state *mas, struct ma_topiary *mat) +{ + struct maple_enode *next; + struct maple_node *node; + bool in_rcu = mt_in_rcu(mas->tree); + + while (mat->head) { + next = mte_to_mat(mat->head)->next; + node = mte_to_node(mat->head); + mt_destroy_walk(mat->head, mas->tree, !in_rcu); + if (in_rcu) + call_rcu(&node->rcu, mt_free_walk); + mat->head = next; + } +} +/* + * mas_descend() - Descend into the slot stored in the ma_state. + * @mas - the maple state. + * + * Note: Not RCU safe, only use in write side or debug code. + */ +static inline void mas_descend(struct ma_state *mas) +{ + enum maple_type type; + unsigned long *pivots; + struct maple_node *node; + void __rcu **slots; + + node = mas_mn(mas); + type = mte_node_type(mas->node); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + + if (mas->offset) + mas->min = pivots[mas->offset - 1] + 1; + mas->max = mas_safe_pivot(mas, pivots, mas->offset, type); + mas->node = mas_slot(mas, slots, mas->offset); +} + +/* + * mte_set_gap() - Set a maple node gap. + * @mn: The encoded maple node + * @gap: The offset of the gap to set + * @val: The gap value + */ +static inline void mte_set_gap(const struct maple_enode *mn, + unsigned char gap, unsigned long val) +{ + switch (mte_node_type(mn)) { + default: + break; + case maple_arange_64: + mte_to_node(mn)->ma64.gap[gap] = val; + break; + } +} + +/* + * mas_ascend() - Walk up a level of the tree. + * @mas: The maple state + * + * Sets the @mas->max and @mas->min to the correct values when walking up. This + * may cause several levels of walking up to find the correct min and max. + * May find a dead node which will cause a premature return. + * Return: 1 on dead node, 0 otherwise + */ +static int mas_ascend(struct ma_state *mas) +{ + struct maple_enode *p_enode; /* parent enode. */ + struct maple_enode *a_enode; /* ancestor enode. */ + struct maple_node *a_node; /* ancestor node. */ + struct maple_node *p_node; /* parent node. */ + unsigned char a_slot; + enum maple_type a_type; + unsigned long min, max; + unsigned long *pivots; + bool set_max = false, set_min = false; + + a_node = mas_mn(mas); + if (ma_is_root(a_node)) { + mas->offset = 0; + return 0; + } + + p_node = mte_parent(mas->node); + if (unlikely(a_node == p_node)) + return 1; + + a_type = mas_parent_type(mas, mas->node); + mas->offset = mte_parent_slot(mas->node); + a_enode = mt_mk_node(p_node, a_type); + + /* Check to make sure all parent information is still accurate */ + if (p_node != mte_parent(mas->node)) + return 1; + + mas->node = a_enode; + + if (mte_is_root(a_enode)) { + mas->max = ULONG_MAX; + mas->min = 0; + return 0; + } + + min = 0; + max = ULONG_MAX; + if (!mas->offset) { + min = mas->min; + set_min = true; + } + + if (mas->max == ULONG_MAX) + set_max = true; + + do { + p_enode = a_enode; + a_type = mas_parent_type(mas, p_enode); + a_node = mte_parent(p_enode); + a_slot = mte_parent_slot(p_enode); + a_enode = mt_mk_node(a_node, a_type); + pivots = ma_pivots(a_node, a_type); + + if (unlikely(ma_dead_node(a_node))) + return 1; + + if (!set_min && a_slot) { + set_min = true; + min = pivots[a_slot - 1] + 1; + } + + if (!set_max && a_slot < mt_pivots[a_type]) { + set_max = true; + max = pivots[a_slot]; + } + + if (unlikely(ma_dead_node(a_node))) + return 1; + + if (unlikely(ma_is_root(a_node))) + break; + + } while (!set_min || !set_max); + + mas->max = max; + mas->min = min; + return 0; +} + +/* + * mas_pop_node() - Get a previously allocated maple node from the maple state. + * @mas: The maple state + * + * Return: A pointer to a maple node. + */ +static inline struct maple_node *mas_pop_node(struct ma_state *mas) +{ + struct maple_alloc *ret, *node = mas->alloc; + unsigned long total = mas_allocated(mas); + unsigned int req = mas_alloc_req(mas); + + /* nothing or a request pending. */ + if (WARN_ON(!total)) + return NULL; + + if (total == 1) { + /* single allocation in this ma_state */ + mas->alloc = NULL; + ret = node; + goto single_node; + } + + if (node->node_count == 1) { + /* Single allocation in this node. */ + mas->alloc = node->slot[0]; + mas->alloc->total = node->total - 1; + ret = node; + goto new_head; + } + node->total--; + ret = node->slot[--node->node_count]; + node->slot[node->node_count] = NULL; + +single_node: +new_head: + if (req) { + req++; + mas_set_alloc_req(mas, req); + } + + memset(ret, 0, sizeof(*ret)); + return (struct maple_node *)ret; +} + +/* + * mas_push_node() - Push a node back on the maple state allocation. + * @mas: The maple state + * @used: The used maple node + * + * Stores the maple node back into @mas->alloc for reuse. Updates allocated and + * requested node count as necessary. + */ +static inline void mas_push_node(struct ma_state *mas, struct maple_node *used) +{ + struct maple_alloc *reuse = (struct maple_alloc *)used; + struct maple_alloc *head = mas->alloc; + unsigned long count; + unsigned int requested = mas_alloc_req(mas); + + count = mas_allocated(mas); + + reuse->request_count = 0; + reuse->node_count = 0; + if (count && (head->node_count < MAPLE_ALLOC_SLOTS)) { + head->slot[head->node_count++] = reuse; + head->total++; + goto done; + } + + reuse->total = 1; + if ((head) && !((unsigned long)head & 0x1)) { + reuse->slot[0] = head; + reuse->node_count = 1; + reuse->total += head->total; + } + + mas->alloc = reuse; +done: + if (requested > 1) + mas_set_alloc_req(mas, requested - 1); +} + +/* + * mas_alloc_nodes() - Allocate nodes into a maple state + * @mas: The maple state + * @gfp: The GFP Flags + */ +static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp) +{ + struct maple_alloc *node; + unsigned long allocated = mas_allocated(mas); + unsigned int requested = mas_alloc_req(mas); + unsigned int count; + void **slots = NULL; + unsigned int max_req = 0; + + if (!requested) + return; + + mas_set_alloc_req(mas, 0); + if (mas->mas_flags & MA_STATE_PREALLOC) { + if (allocated) + return; + BUG_ON(!allocated); + WARN_ON(!allocated); + } + + if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS) { + node = (struct maple_alloc *)mt_alloc_one(gfp); + if (!node) + goto nomem_one; + + if (allocated) { + node->slot[0] = mas->alloc; + node->node_count = 1; + } else { + node->node_count = 0; + } + + mas->alloc = node; + node->total = ++allocated; + requested--; + } + + node = mas->alloc; + node->request_count = 0; + while (requested) { + max_req = MAPLE_ALLOC_SLOTS - node->node_count; + slots = (void **)&node->slot[node->node_count]; + max_req = min(requested, max_req); + count = mt_alloc_bulk(gfp, max_req, slots); + if (!count) + goto nomem_bulk; + + if (node->node_count == 0) { + node->slot[0]->node_count = 0; + node->slot[0]->request_count = 0; + } + + node->node_count += count; + allocated += count; + node = node->slot[0]; + requested -= count; + } + mas->alloc->total = allocated; + return; + +nomem_bulk: + /* Clean up potential freed allocations on bulk failure */ + memset(slots, 0, max_req * sizeof(unsigned long)); +nomem_one: + mas_set_alloc_req(mas, requested); + if (mas->alloc && !(((unsigned long)mas->alloc & 0x1))) + mas->alloc->total = allocated; + mas_set_err(mas, -ENOMEM); +} + +/* + * mas_free() - Free an encoded maple node + * @mas: The maple state + * @used: The encoded maple node to free. + * + * Uses rcu free if necessary, pushes @used back on the maple state allocations + * otherwise. + */ +static inline void mas_free(struct ma_state *mas, struct maple_enode *used) +{ + struct maple_node *tmp = mte_to_node(used); + + if (mt_in_rcu(mas->tree)) + ma_free_rcu(tmp); + else + mas_push_node(mas, tmp); +} + +/* + * mas_node_count() - Check if enough nodes are allocated and request more if + * there is not enough nodes. + * @mas: The maple state + * @count: The number of nodes needed + * @gfp: the gfp flags + */ +static void mas_node_count_gfp(struct ma_state *mas, int count, gfp_t gfp) +{ + unsigned long allocated = mas_allocated(mas); + + if (allocated < count) { + mas_set_alloc_req(mas, count - allocated); + mas_alloc_nodes(mas, gfp); + } +} + +/* + * mas_node_count() - Check if enough nodes are allocated and request more if + * there is not enough nodes. + * @mas: The maple state + * @count: The number of nodes needed + * + * Note: Uses GFP_NOWAIT | __GFP_NOWARN for gfp flags. + */ +static void mas_node_count(struct ma_state *mas, int count) +{ + return mas_node_count_gfp(mas, count, GFP_NOWAIT | __GFP_NOWARN); +} + +/* + * mas_start() - Sets up maple state for operations. + * @mas: The maple state. + * + * If mas->status == mas_start, then set the min, max and depth to + * defaults. + * + * Return: + * - If mas->node is an error or not mas_start, return NULL. + * - If it's an empty tree: NULL & mas->status == ma_none + * - If it's a single entry: The entry & mas->status == mas_root + * - If it's a tree: NULL & mas->status == safe root node. + */ +static inline struct maple_enode *mas_start(struct ma_state *mas) +{ + if (likely(mas_is_start(mas))) { + struct maple_enode *root; + + mas->min = 0; + mas->max = ULONG_MAX; + +retry: + mas->depth = 0; + root = mas_root(mas); + /* Tree with nodes */ + if (likely(xa_is_node(root))) { + mas->depth = 1; + mas->status = ma_active; + mas->node = mte_safe_root(root); + mas->offset = 0; + if (mte_dead_node(mas->node)) + goto retry; + + return NULL; + } + + /* empty tree */ + if (unlikely(!root)) { + mas->node = NULL; + mas->status = ma_none; + mas->offset = MAPLE_NODE_SLOTS; + return NULL; + } + + /* Single entry tree */ + mas->status = ma_root; + mas->offset = MAPLE_NODE_SLOTS; + + /* Single entry tree. */ + if (mas->index > 0) + return NULL; + + return root; + } + + return NULL; +} + +/* + * ma_data_end() - Find the end of the data in a node. + * @node: The maple node + * @type: The maple node type + * @pivots: The array of pivots in the node + * @max: The maximum value in the node + * + * Uses metadata to find the end of the data when possible. + * Return: The zero indexed last slot with data (may be null). + */ +static __always_inline unsigned char ma_data_end(struct maple_node *node, + enum maple_type type, unsigned long *pivots, unsigned long max) +{ + unsigned char offset; + + if (!pivots) + return 0; + + if (type == maple_arange_64) + return ma_meta_end(node, type); + + offset = mt_pivots[type] - 1; + if (likely(!pivots[offset])) + return ma_meta_end(node, type); + + if (likely(pivots[offset] == max)) + return offset; + + return mt_pivots[type]; +} + +/* + * mas_data_end() - Find the end of the data (slot). + * @mas: the maple state + * + * This method is optimized to check the metadata of a node if the node type + * supports data end metadata. + * + * Return: The zero indexed last slot with data (may be null). + */ +static inline unsigned char mas_data_end(struct ma_state *mas) +{ + enum maple_type type; + struct maple_node *node; + unsigned char offset; + unsigned long *pivots; + + type = mte_node_type(mas->node); + node = mas_mn(mas); + if (type == maple_arange_64) + return ma_meta_end(node, type); + + pivots = ma_pivots(node, type); + if (unlikely(ma_dead_node(node))) + return 0; + + offset = mt_pivots[type] - 1; + if (likely(!pivots[offset])) + return ma_meta_end(node, type); + + if (likely(pivots[offset] == mas->max)) + return offset; + + return mt_pivots[type]; +} + +/* + * mas_leaf_max_gap() - Returns the largest gap in a leaf node + * @mas - the maple state + * + * Return: The maximum gap in the leaf. + */ +static unsigned long mas_leaf_max_gap(struct ma_state *mas) +{ + enum maple_type mt; + unsigned long pstart, gap, max_gap; + struct maple_node *mn; + unsigned long *pivots; + void __rcu **slots; + unsigned char i; + unsigned char max_piv; + + mt = mte_node_type(mas->node); + mn = mas_mn(mas); + slots = ma_slots(mn, mt); + max_gap = 0; + if (unlikely(ma_is_dense(mt))) { + gap = 0; + for (i = 0; i < mt_slots[mt]; i++) { + if (slots[i]) { + if (gap > max_gap) + max_gap = gap; + gap = 0; + } else { + gap++; + } + } + if (gap > max_gap) + max_gap = gap; + return max_gap; + } + + /* + * Check the first implied pivot optimizes the loop below and slot 1 may + * be skipped if there is a gap in slot 0. + */ + pivots = ma_pivots(mn, mt); + if (likely(!slots[0])) { + max_gap = pivots[0] - mas->min + 1; + i = 2; + } else { + i = 1; + } + + /* reduce max_piv as the special case is checked before the loop */ + max_piv = ma_data_end(mn, mt, pivots, mas->max) - 1; + /* + * Check end implied pivot which can only be a gap on the right most + * node. + */ + if (unlikely(mas->max == ULONG_MAX) && !slots[max_piv + 1]) { + gap = ULONG_MAX - pivots[max_piv]; + if (gap > max_gap) + max_gap = gap; + + if (max_gap > pivots[max_piv] - mas->min) + return max_gap; + } + + for (; i <= max_piv; i++) { + /* data == no gap. */ + if (likely(slots[i])) + continue; + + pstart = pivots[i - 1]; + gap = pivots[i] - pstart; + if (gap > max_gap) + max_gap = gap; + + /* There cannot be two gaps in a row. */ + i++; + } + return max_gap; +} + +/* + * ma_max_gap() - Get the maximum gap in a maple node (non-leaf) + * @node: The maple node + * @gaps: The pointer to the gaps + * @mt: The maple node type + * @*off: Pointer to store the offset location of the gap. + * + * Uses the metadata data end to scan backwards across set gaps. + * + * Return: The maximum gap value + */ +static inline unsigned long +ma_max_gap(struct maple_node *node, unsigned long *gaps, enum maple_type mt, + unsigned char *off) +{ + unsigned char offset, i; + unsigned long max_gap = 0; + + i = offset = ma_meta_end(node, mt); + do { + if (gaps[i] > max_gap) { + max_gap = gaps[i]; + offset = i; + } + } while (i--); + + *off = offset; + return max_gap; +} + +/* + * mas_max_gap() - find the largest gap in a non-leaf node and set the slot. + * @mas: The maple state. + * + * Return: The gap value. + */ +static inline unsigned long mas_max_gap(struct ma_state *mas) +{ + unsigned long *gaps; + unsigned char offset; + enum maple_type mt; + struct maple_node *node; + + mt = mte_node_type(mas->node); + if (ma_is_leaf(mt)) + return mas_leaf_max_gap(mas); + + node = mas_mn(mas); + MAS_BUG_ON(mas, mt != maple_arange_64); + offset = ma_meta_gap(node); + gaps = ma_gaps(node, mt); + return gaps[offset]; +} + +/* + * mas_parent_gap() - Set the parent gap and any gaps above, as needed + * @mas: The maple state + * @offset: The gap offset in the parent to set + * @new: The new gap value. + * + * Set the parent gap then continue to set the gap upwards, using the metadata + * of the parent to see if it is necessary to check the node above. + */ +static inline void mas_parent_gap(struct ma_state *mas, unsigned char offset, + unsigned long new) +{ + unsigned long meta_gap = 0; + struct maple_node *pnode; + struct maple_enode *penode; + unsigned long *pgaps; + unsigned char meta_offset; + enum maple_type pmt; + + pnode = mte_parent(mas->node); + pmt = mas_parent_type(mas, mas->node); + penode = mt_mk_node(pnode, pmt); + pgaps = ma_gaps(pnode, pmt); + +ascend: + MAS_BUG_ON(mas, pmt != maple_arange_64); + meta_offset = ma_meta_gap(pnode); + meta_gap = pgaps[meta_offset]; + + pgaps[offset] = new; + + if (meta_gap == new) + return; + + if (offset != meta_offset) { + if (meta_gap > new) + return; + + ma_set_meta_gap(pnode, pmt, offset); + } else if (new < meta_gap) { + new = ma_max_gap(pnode, pgaps, pmt, &meta_offset); + ma_set_meta_gap(pnode, pmt, meta_offset); + } + + if (ma_is_root(pnode)) + return; + + /* Go to the parent node. */ + pnode = mte_parent(penode); + pmt = mas_parent_type(mas, penode); + pgaps = ma_gaps(pnode, pmt); + offset = mte_parent_slot(penode); + penode = mt_mk_node(pnode, pmt); + goto ascend; +} + +/* + * mas_update_gap() - Update a nodes gaps and propagate up if necessary. + * @mas - the maple state. + */ +static inline void mas_update_gap(struct ma_state *mas) +{ + unsigned char pslot; + unsigned long p_gap; + unsigned long max_gap; + + if (!mt_is_alloc(mas->tree)) + return; + + if (mte_is_root(mas->node)) + return; + + max_gap = mas_max_gap(mas); + + pslot = mte_parent_slot(mas->node); + p_gap = ma_gaps(mte_parent(mas->node), + mas_parent_type(mas, mas->node))[pslot]; + + if (p_gap != max_gap) + mas_parent_gap(mas, pslot, max_gap); +} + +/* + * mas_adopt_children() - Set the parent pointer of all nodes in @parent to + * @parent with the slot encoded. + * @mas - the maple state (for the tree) + * @parent - the maple encoded node containing the children. + */ +static inline void mas_adopt_children(struct ma_state *mas, + struct maple_enode *parent) +{ + enum maple_type type = mte_node_type(parent); + struct maple_node *node = mte_to_node(parent); + void __rcu **slots = ma_slots(node, type); + unsigned long *pivots = ma_pivots(node, type); + struct maple_enode *child; + unsigned char offset; + + offset = ma_data_end(node, type, pivots, mas->max); + do { + child = mas_slot_locked(mas, slots, offset); + mas_set_parent(mas, child, parent, offset); + } while (offset--); +} + +/* + * mas_put_in_tree() - Put a new node in the tree, smp_wmb(), and mark the old + * node as dead. + * @mas - the maple state with the new node + * @old_enode - The old maple encoded node to replace. + */ +static inline void mas_put_in_tree(struct ma_state *mas, + struct maple_enode *old_enode) + __must_hold(mas->tree->ma_lock) +{ + unsigned char offset; + void __rcu **slots; + + if (mte_is_root(mas->node)) { + mas_mn(mas)->parent = ma_parent_ptr(mas_tree_parent(mas)); + rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); + mas_set_height(mas); + } else { + + offset = mte_parent_slot(mas->node); + slots = ma_slots(mte_parent(mas->node), + mas_parent_type(mas, mas->node)); + rcu_assign_pointer(slots[offset], mas->node); + } + + mte_set_node_dead(old_enode); +} + +/* + * mas_replace_node() - Replace a node by putting it in the tree, marking it + * dead, and freeing it. + * the parent encoding to locate the maple node in the tree. + * @mas - the ma_state with @mas->node pointing to the new node. + * @old_enode - The old maple encoded node. + */ +static inline void mas_replace_node(struct ma_state *mas, + struct maple_enode *old_enode) + __must_hold(mas->tree->ma_lock) +{ + mas_put_in_tree(mas, old_enode); + mas_free(mas, old_enode); +} + +/* + * mas_find_child() - Find a child who has the parent @mas->node. + * @mas: the maple state with the parent. + * @child: the maple state to store the child. + */ +static inline bool mas_find_child(struct ma_state *mas, struct ma_state *child) + __must_hold(mas->tree->ma_lock) +{ + enum maple_type mt; + unsigned char offset; + unsigned char end; + unsigned long *pivots; + struct maple_enode *entry; + struct maple_node *node; + void __rcu **slots; + + mt = mte_node_type(mas->node); + node = mas_mn(mas); + slots = ma_slots(node, mt); + pivots = ma_pivots(node, mt); + end = ma_data_end(node, mt, pivots, mas->max); + for (offset = mas->offset; offset <= end; offset++) { + entry = mas_slot_locked(mas, slots, offset); + if (mte_parent(entry) == node) { + *child = *mas; + mas->offset = offset + 1; + child->offset = offset; + mas_descend(child); + child->offset = 0; + return true; + } + } + return false; +} + +/* + * mab_shift_right() - Shift the data in mab right. Note, does not clean out the + * old data or set b_node->b_end. + * @b_node: the maple_big_node + * @shift: the shift count + */ +static inline void mab_shift_right(struct maple_big_node *b_node, + unsigned char shift) +{ + unsigned long size = b_node->b_end * sizeof(unsigned long); + + memmove(b_node->pivot + shift, b_node->pivot, size); + memmove(b_node->slot + shift, b_node->slot, size); + if (b_node->type == maple_arange_64) + memmove(b_node->gap + shift, b_node->gap, size); +} + +/* + * mab_middle_node() - Check if a middle node is needed (unlikely) + * @b_node: the maple_big_node that contains the data. + * @size: the amount of data in the b_node + * @split: the potential split location + * @slot_count: the size that can be stored in a single node being considered. + * + * Return: true if a middle node is required. + */ +static inline bool mab_middle_node(struct maple_big_node *b_node, int split, + unsigned char slot_count) +{ + unsigned char size = b_node->b_end; + + if (size >= 2 * slot_count) + return true; + + if (!b_node->slot[split] && (size >= 2 * slot_count - 1)) + return true; + + return false; +} + +/* + * mab_no_null_split() - ensure the split doesn't fall on a NULL + * @b_node: the maple_big_node with the data + * @split: the suggested split location + * @slot_count: the number of slots in the node being considered. + * + * Return: the split location. + */ +static inline int mab_no_null_split(struct maple_big_node *b_node, + unsigned char split, unsigned char slot_count) +{ + if (!b_node->slot[split]) { + /* + * If the split is less than the max slot && the right side will + * still be sufficient, then increment the split on NULL. + */ + if ((split < slot_count - 1) && + (b_node->b_end - split) > (mt_min_slots[b_node->type])) + split++; + else + split--; + } + return split; +} + +/* + * mab_calc_split() - Calculate the split location and if there needs to be two + * splits. + * @bn: The maple_big_node with the data + * @mid_split: The second split, if required. 0 otherwise. + * + * Return: The first split location. The middle split is set in @mid_split. + */ +static inline int mab_calc_split(struct ma_state *mas, + struct maple_big_node *bn, unsigned char *mid_split, unsigned long min) +{ + unsigned char b_end = bn->b_end; + int split = b_end / 2; /* Assume equal split. */ + unsigned char slot_min, slot_count = mt_slots[bn->type]; + + /* + * To support gap tracking, all NULL entries are kept together and a node cannot + * end on a NULL entry, with the exception of the left-most leaf. The + * limitation means that the split of a node must be checked for this condition + * and be able to put more data in one direction or the other. + */ + if (unlikely((mas->mas_flags & MA_STATE_BULK))) { + *mid_split = 0; + split = b_end - mt_min_slots[bn->type]; + + if (!ma_is_leaf(bn->type)) + return split; + + mas->mas_flags |= MA_STATE_REBALANCE; + if (!bn->slot[split]) + split--; + return split; + } + + /* + * Although extremely rare, it is possible to enter what is known as the 3-way + * split scenario. The 3-way split comes about by means of a store of a range + * that overwrites the end and beginning of two full nodes. The result is a set + * of entries that cannot be stored in 2 nodes. Sometimes, these two nodes can + * also be located in different parent nodes which are also full. This can + * carry upwards all the way to the root in the worst case. + */ + if (unlikely(mab_middle_node(bn, split, slot_count))) { + split = b_end / 3; + *mid_split = split * 2; + } else { + slot_min = mt_min_slots[bn->type]; + + *mid_split = 0; + /* + * Avoid having a range less than the slot count unless it + * causes one node to be deficient. + * NOTE: mt_min_slots is 1 based, b_end and split are zero. + */ + while ((split < slot_count - 1) && + ((bn->pivot[split] - min) < slot_count - 1) && + (b_end - split > slot_min)) + split++; + } + + /* Avoid ending a node on a NULL entry */ + split = mab_no_null_split(bn, split, slot_count); + + if (unlikely(*mid_split)) + *mid_split = mab_no_null_split(bn, *mid_split, slot_count); + + return split; +} + +/* + * mas_mab_cp() - Copy data from a maple state inclusively to a maple_big_node + * and set @b_node->b_end to the next free slot. + * @mas: The maple state + * @mas_start: The starting slot to copy + * @mas_end: The end slot to copy (inclusively) + * @b_node: The maple_big_node to place the data + * @mab_start: The starting location in maple_big_node to store the data. + */ +static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start, + unsigned char mas_end, struct maple_big_node *b_node, + unsigned char mab_start) +{ + enum maple_type mt; + struct maple_node *node; + void __rcu **slots; + unsigned long *pivots, *gaps; + int i = mas_start, j = mab_start; + unsigned char piv_end; + + node = mas_mn(mas); + mt = mte_node_type(mas->node); + pivots = ma_pivots(node, mt); + if (!i) { + b_node->pivot[j] = pivots[i++]; + if (unlikely(i > mas_end)) + goto complete; + j++; + } + + piv_end = min(mas_end, mt_pivots[mt]); + for (; i < piv_end; i++, j++) { + b_node->pivot[j] = pivots[i]; + if (unlikely(!b_node->pivot[j])) + break; + + if (unlikely(mas->max == b_node->pivot[j])) + goto complete; + } + + if (likely(i <= mas_end)) + b_node->pivot[j] = mas_safe_pivot(mas, pivots, i, mt); + +complete: + b_node->b_end = ++j; + j -= mab_start; + slots = ma_slots(node, mt); + memcpy(b_node->slot + mab_start, slots + mas_start, sizeof(void *) * j); + if (!ma_is_leaf(mt) && mt_is_alloc(mas->tree)) { + gaps = ma_gaps(node, mt); + memcpy(b_node->gap + mab_start, gaps + mas_start, + sizeof(unsigned long) * j); + } +} + +/* + * mas_leaf_set_meta() - Set the metadata of a leaf if possible. + * @node: The maple node + * @mt: The maple type + * @end: The node end + */ +static inline void mas_leaf_set_meta(struct maple_node *node, + enum maple_type mt, unsigned char end) +{ + if (end < mt_slots[mt] - 1) + ma_set_meta(node, mt, 0, end); +} + +/* + * mab_mas_cp() - Copy data from maple_big_node to a maple encoded node. + * @b_node: the maple_big_node that has the data + * @mab_start: the start location in @b_node. + * @mab_end: The end location in @b_node (inclusively) + * @mas: The maple state with the maple encoded node. + */ +static inline void mab_mas_cp(struct maple_big_node *b_node, + unsigned char mab_start, unsigned char mab_end, + struct ma_state *mas, bool new_max) +{ + int i, j = 0; + enum maple_type mt = mte_node_type(mas->node); + struct maple_node *node = mte_to_node(mas->node); + void __rcu **slots = ma_slots(node, mt); + unsigned long *pivots = ma_pivots(node, mt); + unsigned long *gaps = NULL; + unsigned char end; + + if (mab_end - mab_start > mt_pivots[mt]) + mab_end--; + + if (!pivots[mt_pivots[mt] - 1]) + slots[mt_pivots[mt]] = NULL; + + i = mab_start; + do { + pivots[j++] = b_node->pivot[i++]; + } while (i <= mab_end && likely(b_node->pivot[i])); + + memcpy(slots, b_node->slot + mab_start, + sizeof(void *) * (i - mab_start)); + + if (new_max) + mas->max = b_node->pivot[i - 1]; + + end = j - 1; + if (likely(!ma_is_leaf(mt) && mt_is_alloc(mas->tree))) { + unsigned long max_gap = 0; + unsigned char offset = 0; + + gaps = ma_gaps(node, mt); + do { + gaps[--j] = b_node->gap[--i]; + if (gaps[j] > max_gap) { + offset = j; + max_gap = gaps[j]; + } + } while (j); + + ma_set_meta(node, mt, offset, end); + } else { + mas_leaf_set_meta(node, mt, end); + } +} + +/* + * mas_bulk_rebalance() - Rebalance the end of a tree after a bulk insert. + * @mas: The maple state + * @end: The maple node end + * @mt: The maple node type + */ +static inline void mas_bulk_rebalance(struct ma_state *mas, unsigned char end, + enum maple_type mt) +{ + if (!(mas->mas_flags & MA_STATE_BULK)) + return; + + if (mte_is_root(mas->node)) + return; + + if (end > mt_min_slots[mt]) { + mas->mas_flags &= ~MA_STATE_REBALANCE; + return; + } +} + +/* + * mas_store_b_node() - Store an @entry into the b_node while also copying the + * data from a maple encoded node. + * @wr_mas: the maple write state + * @b_node: the maple_big_node to fill with data + * @offset_end: the offset to end copying + * + * Return: The actual end of the data stored in @b_node + */ +static noinline_for_kasan void mas_store_b_node(struct ma_wr_state *wr_mas, + struct maple_big_node *b_node, unsigned char offset_end) +{ + unsigned char slot; + unsigned char b_end; + /* Possible underflow of piv will wrap back to 0 before use. */ + unsigned long piv; + struct ma_state *mas = wr_mas->mas; + + b_node->type = wr_mas->type; + b_end = 0; + slot = mas->offset; + if (slot) { + /* Copy start data up to insert. */ + mas_mab_cp(mas, 0, slot - 1, b_node, 0); + b_end = b_node->b_end; + piv = b_node->pivot[b_end - 1]; + } else + piv = mas->min - 1; + + if (piv + 1 < mas->index) { + /* Handle range starting after old range */ + b_node->slot[b_end] = wr_mas->content; + if (!wr_mas->content) + b_node->gap[b_end] = mas->index - 1 - piv; + b_node->pivot[b_end++] = mas->index - 1; + } + + /* Store the new entry. */ + mas->offset = b_end; + b_node->slot[b_end] = wr_mas->entry; + b_node->pivot[b_end] = mas->last; + + /* Appended. */ + if (mas->last >= mas->max) + goto b_end; + + /* Handle new range ending before old range ends */ + piv = mas_safe_pivot(mas, wr_mas->pivots, offset_end, wr_mas->type); + if (piv > mas->last) { + if (piv == ULONG_MAX) + mas_bulk_rebalance(mas, b_node->b_end, wr_mas->type); + + if (offset_end != slot) + wr_mas->content = mas_slot_locked(mas, wr_mas->slots, + offset_end); + + b_node->slot[++b_end] = wr_mas->content; + if (!wr_mas->content) + b_node->gap[b_end] = piv - mas->last + 1; + b_node->pivot[b_end] = piv; + } + + slot = offset_end + 1; + if (slot > mas->end) + goto b_end; + + /* Copy end data to the end of the node. */ + mas_mab_cp(mas, slot, mas->end + 1, b_node, ++b_end); + b_node->b_end--; + return; + +b_end: + b_node->b_end = b_end; +} + +/* + * mas_prev_sibling() - Find the previous node with the same parent. + * @mas: the maple state + * + * Return: True if there is a previous sibling, false otherwise. + */ +static inline bool mas_prev_sibling(struct ma_state *mas) +{ + unsigned int p_slot = mte_parent_slot(mas->node); + + if (mte_is_root(mas->node)) + return false; + + if (!p_slot) + return false; + + mas_ascend(mas); + mas->offset = p_slot - 1; + mas_descend(mas); + return true; +} + +/* + * mas_next_sibling() - Find the next node with the same parent. + * @mas: the maple state + * + * Return: true if there is a next sibling, false otherwise. + */ +static inline bool mas_next_sibling(struct ma_state *mas) +{ + MA_STATE(parent, mas->tree, mas->index, mas->last); + + if (mte_is_root(mas->node)) + return false; + + parent = *mas; + mas_ascend(&parent); + parent.offset = mte_parent_slot(mas->node) + 1; + if (parent.offset > mas_data_end(&parent)) + return false; + + *mas = parent; + mas_descend(mas); + return true; +} + +/* + * mte_node_or_none() - Set the enode and state. + * @enode: The encoded maple node. + * + * Set the node to the enode and the status. + */ +static inline void mas_node_or_none(struct ma_state *mas, + struct maple_enode *enode) +{ + if (enode) { + mas->node = enode; + mas->status = ma_active; + } else { + mas->node = NULL; + mas->status = ma_none; + } +} + +/* + * mas_wr_node_walk() - Find the correct offset for the index in the @mas. + * @wr_mas: The maple write state + * + * Uses mas_slot_locked() and does not need to worry about dead nodes. + */ +static inline void mas_wr_node_walk(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + unsigned char count, offset; + + if (unlikely(ma_is_dense(wr_mas->type))) { + wr_mas->r_max = wr_mas->r_min = mas->index; + mas->offset = mas->index = mas->min; + return; + } + + wr_mas->node = mas_mn(wr_mas->mas); + wr_mas->pivots = ma_pivots(wr_mas->node, wr_mas->type); + count = mas->end = ma_data_end(wr_mas->node, wr_mas->type, + wr_mas->pivots, mas->max); + offset = mas->offset; + + while (offset < count && mas->index > wr_mas->pivots[offset]) + offset++; + + wr_mas->r_max = offset < count ? wr_mas->pivots[offset] : mas->max; + wr_mas->r_min = mas_safe_min(mas, wr_mas->pivots, offset); + wr_mas->offset_end = mas->offset = offset; +} + +/* + * mast_rebalance_next() - Rebalance against the next node + * @mast: The maple subtree state + * @old_r: The encoded maple node to the right (next node). + */ +static inline void mast_rebalance_next(struct maple_subtree_state *mast) +{ + unsigned char b_end = mast->bn->b_end; + + mas_mab_cp(mast->orig_r, 0, mt_slot_count(mast->orig_r->node), + mast->bn, b_end); + mast->orig_r->last = mast->orig_r->max; +} + +/* + * mast_rebalance_prev() - Rebalance against the previous node + * @mast: The maple subtree state + * @old_l: The encoded maple node to the left (previous node) + */ +static inline void mast_rebalance_prev(struct maple_subtree_state *mast) +{ + unsigned char end = mas_data_end(mast->orig_l) + 1; + unsigned char b_end = mast->bn->b_end; + + mab_shift_right(mast->bn, end); + mas_mab_cp(mast->orig_l, 0, end - 1, mast->bn, 0); + mast->l->min = mast->orig_l->min; + mast->orig_l->index = mast->orig_l->min; + mast->bn->b_end = end + b_end; + mast->l->offset += end; +} + +/* + * mast_spanning_rebalance() - Rebalance nodes with nearest neighbour favouring + * the node to the right. Checking the nodes to the right then the left at each + * level upwards until root is reached. + * Data is copied into the @mast->bn. + * @mast: The maple_subtree_state. + */ +static inline +bool mast_spanning_rebalance(struct maple_subtree_state *mast) +{ + struct ma_state r_tmp = *mast->orig_r; + struct ma_state l_tmp = *mast->orig_l; + unsigned char depth = 0; + + r_tmp = *mast->orig_r; + l_tmp = *mast->orig_l; + do { + mas_ascend(mast->orig_r); + mas_ascend(mast->orig_l); + depth++; + if (mast->orig_r->offset < mas_data_end(mast->orig_r)) { + mast->orig_r->offset++; + do { + mas_descend(mast->orig_r); + mast->orig_r->offset = 0; + } while (--depth); + + mast_rebalance_next(mast); + *mast->orig_l = l_tmp; + return true; + } else if (mast->orig_l->offset != 0) { + mast->orig_l->offset--; + do { + mas_descend(mast->orig_l); + mast->orig_l->offset = + mas_data_end(mast->orig_l); + } while (--depth); + + mast_rebalance_prev(mast); + *mast->orig_r = r_tmp; + return true; + } + } while (!mte_is_root(mast->orig_r->node)); + + *mast->orig_r = r_tmp; + *mast->orig_l = l_tmp; + return false; +} + +/* + * mast_ascend() - Ascend the original left and right maple states. + * @mast: the maple subtree state. + * + * Ascend the original left and right sides. Set the offsets to point to the + * data already in the new tree (@mast->l and @mast->r). + */ +static inline void mast_ascend(struct maple_subtree_state *mast) +{ + MA_WR_STATE(wr_mas, mast->orig_r, NULL); + mas_ascend(mast->orig_l); + mas_ascend(mast->orig_r); + + mast->orig_r->offset = 0; + mast->orig_r->index = mast->r->max; + /* last should be larger than or equal to index */ + if (mast->orig_r->last < mast->orig_r->index) + mast->orig_r->last = mast->orig_r->index; + + wr_mas.type = mte_node_type(mast->orig_r->node); + mas_wr_node_walk(&wr_mas); + /* Set up the left side of things */ + mast->orig_l->offset = 0; + mast->orig_l->index = mast->l->min; + wr_mas.mas = mast->orig_l; + wr_mas.type = mte_node_type(mast->orig_l->node); + mas_wr_node_walk(&wr_mas); + + mast->bn->type = wr_mas.type; +} + +/* + * mas_new_ma_node() - Create and return a new maple node. Helper function. + * @mas: the maple state with the allocations. + * @b_node: the maple_big_node with the type encoding. + * + * Use the node type from the maple_big_node to allocate a new node from the + * ma_state. This function exists mainly for code readability. + * + * Return: A new maple encoded node + */ +static inline struct maple_enode +*mas_new_ma_node(struct ma_state *mas, struct maple_big_node *b_node) +{ + return mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)), b_node->type); +} + +/* + * mas_mab_to_node() - Set up right and middle nodes + * + * @mas: the maple state that contains the allocations. + * @b_node: the node which contains the data. + * @left: The pointer which will have the left node + * @right: The pointer which may have the right node + * @middle: the pointer which may have the middle node (rare) + * @mid_split: the split location for the middle node + * + * Return: the split of left. + */ +static inline unsigned char mas_mab_to_node(struct ma_state *mas, + struct maple_big_node *b_node, struct maple_enode **left, + struct maple_enode **right, struct maple_enode **middle, + unsigned char *mid_split, unsigned long min) +{ + unsigned char split = 0; + unsigned char slot_count = mt_slots[b_node->type]; + + *left = mas_new_ma_node(mas, b_node); + *right = NULL; + *middle = NULL; + *mid_split = 0; + + if (b_node->b_end < slot_count) { + split = b_node->b_end; + } else { + split = mab_calc_split(mas, b_node, mid_split, min); + *right = mas_new_ma_node(mas, b_node); + } + + if (*mid_split) + *middle = mas_new_ma_node(mas, b_node); + + return split; + +} + +/* + * mab_set_b_end() - Add entry to b_node at b_node->b_end and increment the end + * pointer. + * @b_node - the big node to add the entry + * @mas - the maple state to get the pivot (mas->max) + * @entry - the entry to add, if NULL nothing happens. + */ +static inline void mab_set_b_end(struct maple_big_node *b_node, + struct ma_state *mas, + void *entry) +{ + if (!entry) + return; + + b_node->slot[b_node->b_end] = entry; + if (mt_is_alloc(mas->tree)) + b_node->gap[b_node->b_end] = mas_max_gap(mas); + b_node->pivot[b_node->b_end++] = mas->max; +} + +/* + * mas_set_split_parent() - combine_then_separate helper function. Sets the parent + * of @mas->node to either @left or @right, depending on @slot and @split + * + * @mas - the maple state with the node that needs a parent + * @left - possible parent 1 + * @right - possible parent 2 + * @slot - the slot the mas->node was placed + * @split - the split location between @left and @right + */ +static inline void mas_set_split_parent(struct ma_state *mas, + struct maple_enode *left, + struct maple_enode *right, + unsigned char *slot, unsigned char split) +{ + if (mas_is_none(mas)) + return; + + if ((*slot) <= split) + mas_set_parent(mas, mas->node, left, *slot); + else if (right) + mas_set_parent(mas, mas->node, right, (*slot) - split - 1); + + (*slot)++; +} + +/* + * mte_mid_split_check() - Check if the next node passes the mid-split + * @**l: Pointer to left encoded maple node. + * @**m: Pointer to middle encoded maple node. + * @**r: Pointer to right encoded maple node. + * @slot: The offset + * @*split: The split location. + * @mid_split: The middle split. + */ +static inline void mte_mid_split_check(struct maple_enode **l, + struct maple_enode **r, + struct maple_enode *right, + unsigned char slot, + unsigned char *split, + unsigned char mid_split) +{ + if (*r == right) + return; + + if (slot < mid_split) + return; + + *l = *r; + *r = right; + *split = mid_split; +} + +/* + * mast_set_split_parents() - Helper function to set three nodes parents. Slot + * is taken from @mast->l. + * @mast - the maple subtree state + * @left - the left node + * @right - the right node + * @split - the split location. + */ +static inline void mast_set_split_parents(struct maple_subtree_state *mast, + struct maple_enode *left, + struct maple_enode *middle, + struct maple_enode *right, + unsigned char split, + unsigned char mid_split) +{ + unsigned char slot; + struct maple_enode *l = left; + struct maple_enode *r = right; + + if (mas_is_none(mast->l)) + return; + + if (middle) + r = middle; + + slot = mast->l->offset; + + mte_mid_split_check(&l, &r, right, slot, &split, mid_split); + mas_set_split_parent(mast->l, l, r, &slot, split); + + mte_mid_split_check(&l, &r, right, slot, &split, mid_split); + mas_set_split_parent(mast->m, l, r, &slot, split); + + mte_mid_split_check(&l, &r, right, slot, &split, mid_split); + mas_set_split_parent(mast->r, l, r, &slot, split); +} + +/* + * mas_topiary_node() - Dispose of a single node + * @mas: The maple state for pushing nodes + * @enode: The encoded maple node + * @in_rcu: If the tree is in rcu mode + * + * The node will either be RCU freed or pushed back on the maple state. + */ +static inline void mas_topiary_node(struct ma_state *mas, + struct ma_state *tmp_mas, bool in_rcu) +{ + struct maple_node *tmp; + struct maple_enode *enode; + + if (mas_is_none(tmp_mas)) + return; + + enode = tmp_mas->node; + tmp = mte_to_node(enode); + mte_set_node_dead(enode); + if (in_rcu) + ma_free_rcu(tmp); + else + mas_push_node(mas, tmp); +} + +/* + * mas_topiary_replace() - Replace the data with new data, then repair the + * parent links within the new tree. Iterate over the dead sub-tree and collect + * the dead subtrees and topiary the nodes that are no longer of use. + * + * The new tree will have up to three children with the correct parent. Keep + * track of the new entries as they need to be followed to find the next level + * of new entries. + * + * The old tree will have up to three children with the old parent. Keep track + * of the old entries as they may have more nodes below replaced. Nodes within + * [index, last] are dead subtrees, others need to be freed and followed. + * + * @mas: The maple state pointing at the new data + * @old_enode: The maple encoded node being replaced + * + */ +static inline void mas_topiary_replace(struct ma_state *mas, + struct maple_enode *old_enode) +{ + struct ma_state tmp[3], tmp_next[3]; + MA_TOPIARY(subtrees, mas->tree); + bool in_rcu; + int i, n; + + /* Place data in tree & then mark node as old */ + mas_put_in_tree(mas, old_enode); + + /* Update the parent pointers in the tree */ + tmp[0] = *mas; + tmp[0].offset = 0; + tmp[1].status = ma_none; + tmp[2].status = ma_none; + while (!mte_is_leaf(tmp[0].node)) { + n = 0; + for (i = 0; i < 3; i++) { + if (mas_is_none(&tmp[i])) + continue; + + while (n < 3) { + if (!mas_find_child(&tmp[i], &tmp_next[n])) + break; + n++; + } + + mas_adopt_children(&tmp[i], tmp[i].node); + } + + if (MAS_WARN_ON(mas, n == 0)) + break; + + while (n < 3) + tmp_next[n++].status = ma_none; + + for (i = 0; i < 3; i++) + tmp[i] = tmp_next[i]; + } + + /* Collect the old nodes that need to be discarded */ + if (mte_is_leaf(old_enode)) + return mas_free(mas, old_enode); + + tmp[0] = *mas; + tmp[0].offset = 0; + tmp[0].node = old_enode; + tmp[1].status = ma_none; + tmp[2].status = ma_none; + in_rcu = mt_in_rcu(mas->tree); + do { + n = 0; + for (i = 0; i < 3; i++) { + if (mas_is_none(&tmp[i])) + continue; + + while (n < 3) { + if (!mas_find_child(&tmp[i], &tmp_next[n])) + break; + + if ((tmp_next[n].min >= tmp_next->index) && + (tmp_next[n].max <= tmp_next->last)) { + mat_add(&subtrees, tmp_next[n].node); + tmp_next[n].status = ma_none; + } else { + n++; + } + } + } + + if (MAS_WARN_ON(mas, n == 0)) + break; + + while (n < 3) + tmp_next[n++].status = ma_none; + + for (i = 0; i < 3; i++) { + mas_topiary_node(mas, &tmp[i], in_rcu); + tmp[i] = tmp_next[i]; + } + } while (!mte_is_leaf(tmp[0].node)); + + for (i = 0; i < 3; i++) + mas_topiary_node(mas, &tmp[i], in_rcu); + + mas_mat_destroy(mas, &subtrees); +} + +/* + * mas_wmb_replace() - Write memory barrier and replace + * @mas: The maple state + * @old: The old maple encoded node that is being replaced. + * + * Updates gap as necessary. + */ +static inline void mas_wmb_replace(struct ma_state *mas, + struct maple_enode *old_enode) +{ + /* Insert the new data in the tree */ + mas_topiary_replace(mas, old_enode); + + if (mte_is_leaf(mas->node)) + return; + + mas_update_gap(mas); +} + +/* + * mast_cp_to_nodes() - Copy data out to nodes. + * @mast: The maple subtree state + * @left: The left encoded maple node + * @middle: The middle encoded maple node + * @right: The right encoded maple node + * @split: The location to split between left and (middle ? middle : right) + * @mid_split: The location to split between middle and right. + */ +static inline void mast_cp_to_nodes(struct maple_subtree_state *mast, + struct maple_enode *left, struct maple_enode *middle, + struct maple_enode *right, unsigned char split, unsigned char mid_split) +{ + bool new_lmax = true; + + mas_node_or_none(mast->l, left); + mas_node_or_none(mast->m, middle); + mas_node_or_none(mast->r, right); + + mast->l->min = mast->orig_l->min; + if (split == mast->bn->b_end) { + mast->l->max = mast->orig_r->max; + new_lmax = false; + } + + mab_mas_cp(mast->bn, 0, split, mast->l, new_lmax); + + if (middle) { + mab_mas_cp(mast->bn, 1 + split, mid_split, mast->m, true); + mast->m->min = mast->bn->pivot[split] + 1; + split = mid_split; + } + + mast->r->max = mast->orig_r->max; + if (right) { + mab_mas_cp(mast->bn, 1 + split, mast->bn->b_end, mast->r, false); + mast->r->min = mast->bn->pivot[split] + 1; + } +} + +/* + * mast_combine_cp_left - Copy in the original left side of the tree into the + * combined data set in the maple subtree state big node. + * @mast: The maple subtree state + */ +static inline void mast_combine_cp_left(struct maple_subtree_state *mast) +{ + unsigned char l_slot = mast->orig_l->offset; + + if (!l_slot) + return; + + mas_mab_cp(mast->orig_l, 0, l_slot - 1, mast->bn, 0); +} + +/* + * mast_combine_cp_right: Copy in the original right side of the tree into the + * combined data set in the maple subtree state big node. + * @mast: The maple subtree state + */ +static inline void mast_combine_cp_right(struct maple_subtree_state *mast) +{ + if (mast->bn->pivot[mast->bn->b_end - 1] >= mast->orig_r->max) + return; + + mas_mab_cp(mast->orig_r, mast->orig_r->offset + 1, + mt_slot_count(mast->orig_r->node), mast->bn, + mast->bn->b_end); + mast->orig_r->last = mast->orig_r->max; +} + +/* + * mast_sufficient: Check if the maple subtree state has enough data in the big + * node to create at least one sufficient node + * @mast: the maple subtree state + */ +static inline bool mast_sufficient(struct maple_subtree_state *mast) +{ + if (mast->bn->b_end > mt_min_slot_count(mast->orig_l->node)) + return true; + + return false; +} + +/* + * mast_overflow: Check if there is too much data in the subtree state for a + * single node. + * @mast: The maple subtree state + */ +static inline bool mast_overflow(struct maple_subtree_state *mast) +{ + if (mast->bn->b_end >= mt_slot_count(mast->orig_l->node)) + return true; + + return false; +} + +static inline void *mtree_range_walk(struct ma_state *mas) +{ + unsigned long *pivots; + unsigned char offset; + struct maple_node *node; + struct maple_enode *next, *last; + enum maple_type type; + void __rcu **slots; + unsigned char end; + unsigned long max, min; + unsigned long prev_max, prev_min; + + next = mas->node; + min = mas->min; + max = mas->max; + do { + last = next; + node = mte_to_node(next); + type = mte_node_type(next); + pivots = ma_pivots(node, type); + end = ma_data_end(node, type, pivots, max); + prev_min = min; + prev_max = max; + if (pivots[0] >= mas->index) { + offset = 0; + max = pivots[0]; + goto next; + } + + offset = 1; + while (offset < end) { + if (pivots[offset] >= mas->index) { + max = pivots[offset]; + break; + } + offset++; + } + + min = pivots[offset - 1] + 1; +next: + slots = ma_slots(node, type); + next = mt_slot(mas->tree, slots, offset); + if (unlikely(ma_dead_node(node))) + goto dead_node; + } while (!ma_is_leaf(type)); + + mas->end = end; + mas->offset = offset; + mas->index = min; + mas->last = max; + mas->min = prev_min; + mas->max = prev_max; + mas->node = last; + return (void *)next; + +dead_node: + mas_reset(mas); + return NULL; +} + +/* + * mas_spanning_rebalance() - Rebalance across two nodes which may not be peers. + * @mas: The starting maple state + * @mast: The maple_subtree_state, keeps track of 4 maple states. + * @count: The estimated count of iterations needed. + * + * Follow the tree upwards from @l_mas and @r_mas for @count, or until the root + * is hit. First @b_node is split into two entries which are inserted into the + * next iteration of the loop. @b_node is returned populated with the final + * iteration. @mas is used to obtain allocations. orig_l_mas keeps track of the + * nodes that will remain active by using orig_l_mas->index and orig_l_mas->last + * to account of what has been copied into the new sub-tree. The update of + * orig_l_mas->last is used in mas_consume to find the slots that will need to + * be either freed or destroyed. orig_l_mas->depth keeps track of the height of + * the new sub-tree in case the sub-tree becomes the full tree. + * + * Return: the number of elements in b_node during the last loop. + */ +static int mas_spanning_rebalance(struct ma_state *mas, + struct maple_subtree_state *mast, unsigned char count) +{ + unsigned char split, mid_split; + unsigned char slot = 0; + struct maple_enode *left = NULL, *middle = NULL, *right = NULL; + struct maple_enode *old_enode; + + MA_STATE(l_mas, mas->tree, mas->index, mas->index); + MA_STATE(r_mas, mas->tree, mas->index, mas->last); + MA_STATE(m_mas, mas->tree, mas->index, mas->index); + + /* + * The tree needs to be rebalanced and leaves need to be kept at the same level. + * Rebalancing is done by use of the ``struct maple_topiary``. + */ + mast->l = &l_mas; + mast->m = &m_mas; + mast->r = &r_mas; + l_mas.status = r_mas.status = m_mas.status = ma_none; + + /* Check if this is not root and has sufficient data. */ + if (((mast->orig_l->min != 0) || (mast->orig_r->max != ULONG_MAX)) && + unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type])) + mast_spanning_rebalance(mast); + + l_mas.depth = 0; + + /* + * Each level of the tree is examined and balanced, pushing data to the left or + * right, or rebalancing against left or right nodes is employed to avoid + * rippling up the tree to limit the amount of churn. Once a new sub-section of + * the tree is created, there may be a mix of new and old nodes. The old nodes + * will have the incorrect parent pointers and currently be in two trees: the + * original tree and the partially new tree. To remedy the parent pointers in + * the old tree, the new data is swapped into the active tree and a walk down + * the tree is performed and the parent pointers are updated. + * See mas_topiary_replace() for more information. + */ + while (count--) { + mast->bn->b_end--; + mast->bn->type = mte_node_type(mast->orig_l->node); + split = mas_mab_to_node(mas, mast->bn, &left, &right, &middle, + &mid_split, mast->orig_l->min); + mast_set_split_parents(mast, left, middle, right, split, + mid_split); + mast_cp_to_nodes(mast, left, middle, right, split, mid_split); + + /* + * Copy data from next level in the tree to mast->bn from next + * iteration + */ + memset(mast->bn, 0, sizeof(struct maple_big_node)); + mast->bn->type = mte_node_type(left); + l_mas.depth++; + + /* Root already stored in l->node. */ + if (mas_is_root_limits(mast->l)) + goto new_root; + + mast_ascend(mast); + mast_combine_cp_left(mast); + l_mas.offset = mast->bn->b_end; + mab_set_b_end(mast->bn, &l_mas, left); + mab_set_b_end(mast->bn, &m_mas, middle); + mab_set_b_end(mast->bn, &r_mas, right); + + /* Copy anything necessary out of the right node. */ + mast_combine_cp_right(mast); + mast->orig_l->last = mast->orig_l->max; + + if (mast_sufficient(mast)) + continue; + + if (mast_overflow(mast)) + continue; + + /* May be a new root stored in mast->bn */ + if (mas_is_root_limits(mast->orig_l)) + break; + + mast_spanning_rebalance(mast); + + /* rebalancing from other nodes may require another loop. */ + if (!count) + count++; + } + + l_mas.node = mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)), + mte_node_type(mast->orig_l->node)); + l_mas.depth++; + mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, &l_mas, true); + mas_set_parent(mas, left, l_mas.node, slot); + if (middle) + mas_set_parent(mas, middle, l_mas.node, ++slot); + + if (right) + mas_set_parent(mas, right, l_mas.node, ++slot); + + if (mas_is_root_limits(mast->l)) { +new_root: + mas_mn(mast->l)->parent = ma_parent_ptr(mas_tree_parent(mas)); + while (!mte_is_root(mast->orig_l->node)) + mast_ascend(mast); + } else { + mas_mn(&l_mas)->parent = mas_mn(mast->orig_l)->parent; + } + + old_enode = mast->orig_l->node; + mas->depth = l_mas.depth; + mas->node = l_mas.node; + mas->min = l_mas.min; + mas->max = l_mas.max; + mas->offset = l_mas.offset; + mas_wmb_replace(mas, old_enode); + mtree_range_walk(mas); + return mast->bn->b_end; +} + +/* + * mas_rebalance() - Rebalance a given node. + * @mas: The maple state + * @b_node: The big maple node. + * + * Rebalance two nodes into a single node or two new nodes that are sufficient. + * Continue upwards until tree is sufficient. + * + * Return: the number of elements in b_node during the last loop. + */ +static inline int mas_rebalance(struct ma_state *mas, + struct maple_big_node *b_node) +{ + char empty_count = mas_mt_height(mas); + struct maple_subtree_state mast; + unsigned char shift, b_end = ++b_node->b_end; + + MA_STATE(l_mas, mas->tree, mas->index, mas->last); + MA_STATE(r_mas, mas->tree, mas->index, mas->last); + + trace_ma_op(__func__, mas); + + /* + * Rebalancing occurs if a node is insufficient. Data is rebalanced + * against the node to the right if it exists, otherwise the node to the + * left of this node is rebalanced against this node. If rebalancing + * causes just one node to be produced instead of two, then the parent + * is also examined and rebalanced if it is insufficient. Every level + * tries to combine the data in the same way. If one node contains the + * entire range of the tree, then that node is used as a new root node. + */ + mas_node_count(mas, empty_count * 2 - 1); + if (mas_is_err(mas)) + return 0; + + mast.orig_l = &l_mas; + mast.orig_r = &r_mas; + mast.bn = b_node; + mast.bn->type = mte_node_type(mas->node); + + l_mas = r_mas = *mas; + + if (mas_next_sibling(&r_mas)) { + mas_mab_cp(&r_mas, 0, mt_slot_count(r_mas.node), b_node, b_end); + r_mas.last = r_mas.index = r_mas.max; + } else { + mas_prev_sibling(&l_mas); + shift = mas_data_end(&l_mas) + 1; + mab_shift_right(b_node, shift); + mas->offset += shift; + mas_mab_cp(&l_mas, 0, shift - 1, b_node, 0); + b_node->b_end = shift + b_end; + l_mas.index = l_mas.last = l_mas.min; + } + + return mas_spanning_rebalance(mas, &mast, empty_count); +} + +/* + * mas_destroy_rebalance() - Rebalance left-most node while destroying the maple + * state. + * @mas: The maple state + * @end: The end of the left-most node. + * + * During a mass-insert event (such as forking), it may be necessary to + * rebalance the left-most node when it is not sufficient. + */ +static inline void mas_destroy_rebalance(struct ma_state *mas, unsigned char end) +{ + enum maple_type mt = mte_node_type(mas->node); + struct maple_node reuse, *newnode, *parent, *new_left, *left, *node; + struct maple_enode *eparent, *old_eparent; + unsigned char offset, tmp, split = mt_slots[mt] / 2; + void __rcu **l_slots, **slots; + unsigned long *l_pivs, *pivs, gap; + bool in_rcu = mt_in_rcu(mas->tree); + + MA_STATE(l_mas, mas->tree, mas->index, mas->last); + + l_mas = *mas; + mas_prev_sibling(&l_mas); + + /* set up node. */ + if (in_rcu) { + /* Allocate for both left and right as well as parent. */ + mas_node_count(mas, 3); + if (mas_is_err(mas)) + return; + + newnode = mas_pop_node(mas); + } else { + newnode = &reuse; + } + + node = mas_mn(mas); + newnode->parent = node->parent; + slots = ma_slots(newnode, mt); + pivs = ma_pivots(newnode, mt); + left = mas_mn(&l_mas); + l_slots = ma_slots(left, mt); + l_pivs = ma_pivots(left, mt); + if (!l_slots[split]) + split++; + tmp = mas_data_end(&l_mas) - split; + + memcpy(slots, l_slots + split + 1, sizeof(void *) * tmp); + memcpy(pivs, l_pivs + split + 1, sizeof(unsigned long) * tmp); + pivs[tmp] = l_mas.max; + memcpy(slots + tmp, ma_slots(node, mt), sizeof(void *) * end); + memcpy(pivs + tmp, ma_pivots(node, mt), sizeof(unsigned long) * end); + + l_mas.max = l_pivs[split]; + mas->min = l_mas.max + 1; + old_eparent = mt_mk_node(mte_parent(l_mas.node), + mas_parent_type(&l_mas, l_mas.node)); + tmp += end; + if (!in_rcu) { + unsigned char max_p = mt_pivots[mt]; + unsigned char max_s = mt_slots[mt]; + + if (tmp < max_p) + memset(pivs + tmp, 0, + sizeof(unsigned long) * (max_p - tmp)); + + if (tmp < mt_slots[mt]) + memset(slots + tmp, 0, sizeof(void *) * (max_s - tmp)); + + memcpy(node, newnode, sizeof(struct maple_node)); + ma_set_meta(node, mt, 0, tmp - 1); + mte_set_pivot(old_eparent, mte_parent_slot(l_mas.node), + l_pivs[split]); + + /* Remove data from l_pivs. */ + tmp = split + 1; + memset(l_pivs + tmp, 0, sizeof(unsigned long) * (max_p - tmp)); + memset(l_slots + tmp, 0, sizeof(void *) * (max_s - tmp)); + ma_set_meta(left, mt, 0, split); + eparent = old_eparent; + + goto done; + } + + /* RCU requires replacing both l_mas, mas, and parent. */ + mas->node = mt_mk_node(newnode, mt); + ma_set_meta(newnode, mt, 0, tmp); + + new_left = mas_pop_node(mas); + new_left->parent = left->parent; + mt = mte_node_type(l_mas.node); + slots = ma_slots(new_left, mt); + pivs = ma_pivots(new_left, mt); + memcpy(slots, l_slots, sizeof(void *) * split); + memcpy(pivs, l_pivs, sizeof(unsigned long) * split); + ma_set_meta(new_left, mt, 0, split); + l_mas.node = mt_mk_node(new_left, mt); + + /* replace parent. */ + offset = mte_parent_slot(mas->node); + mt = mas_parent_type(&l_mas, l_mas.node); + parent = mas_pop_node(mas); + slots = ma_slots(parent, mt); + pivs = ma_pivots(parent, mt); + memcpy(parent, mte_to_node(old_eparent), sizeof(struct maple_node)); + rcu_assign_pointer(slots[offset], mas->node); + rcu_assign_pointer(slots[offset - 1], l_mas.node); + pivs[offset - 1] = l_mas.max; + eparent = mt_mk_node(parent, mt); +done: + gap = mas_leaf_max_gap(mas); + mte_set_gap(eparent, mte_parent_slot(mas->node), gap); + gap = mas_leaf_max_gap(&l_mas); + mte_set_gap(eparent, mte_parent_slot(l_mas.node), gap); + mas_ascend(mas); + + if (in_rcu) { + mas_replace_node(mas, old_eparent); + mas_adopt_children(mas, mas->node); + } + + mas_update_gap(mas); +} + +/* + * mas_split_final_node() - Split the final node in a subtree operation. + * @mast: the maple subtree state + * @mas: The maple state + * @height: The height of the tree in case it's a new root. + */ +static inline void mas_split_final_node(struct maple_subtree_state *mast, + struct ma_state *mas, int height) +{ + struct maple_enode *ancestor; + + if (mte_is_root(mas->node)) { + if (mt_is_alloc(mas->tree)) + mast->bn->type = maple_arange_64; + else + mast->bn->type = maple_range_64; + mas->depth = height; + } + /* + * Only a single node is used here, could be root. + * The Big_node data should just fit in a single node. + */ + ancestor = mas_new_ma_node(mas, mast->bn); + mas_set_parent(mas, mast->l->node, ancestor, mast->l->offset); + mas_set_parent(mas, mast->r->node, ancestor, mast->r->offset); + mte_to_node(ancestor)->parent = mas_mn(mas)->parent; + + mast->l->node = ancestor; + mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, mast->l, true); + mas->offset = mast->bn->b_end - 1; +} + +/* + * mast_fill_bnode() - Copy data into the big node in the subtree state + * @mast: The maple subtree state + * @mas: the maple state + * @skip: The number of entries to skip for new nodes insertion. + */ +static inline void mast_fill_bnode(struct maple_subtree_state *mast, + struct ma_state *mas, + unsigned char skip) +{ + bool cp = true; + unsigned char split; + + memset(mast->bn->gap, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->gap)); + memset(mast->bn->slot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->slot)); + memset(mast->bn->pivot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->pivot)); + mast->bn->b_end = 0; + + if (mte_is_root(mas->node)) { + cp = false; + } else { + mas_ascend(mas); + mas->offset = mte_parent_slot(mas->node); + } + + if (cp && mast->l->offset) + mas_mab_cp(mas, 0, mast->l->offset - 1, mast->bn, 0); + + split = mast->bn->b_end; + mab_set_b_end(mast->bn, mast->l, mast->l->node); + mast->r->offset = mast->bn->b_end; + mab_set_b_end(mast->bn, mast->r, mast->r->node); + if (mast->bn->pivot[mast->bn->b_end - 1] == mas->max) + cp = false; + + if (cp) + mas_mab_cp(mas, split + skip, mt_slot_count(mas->node) - 1, + mast->bn, mast->bn->b_end); + + mast->bn->b_end--; + mast->bn->type = mte_node_type(mas->node); +} + +/* + * mast_split_data() - Split the data in the subtree state big node into regular + * nodes. + * @mast: The maple subtree state + * @mas: The maple state + * @split: The location to split the big node + */ +static inline void mast_split_data(struct maple_subtree_state *mast, + struct ma_state *mas, unsigned char split) +{ + unsigned char p_slot; + + mab_mas_cp(mast->bn, 0, split, mast->l, true); + mte_set_pivot(mast->r->node, 0, mast->r->max); + mab_mas_cp(mast->bn, split + 1, mast->bn->b_end, mast->r, false); + mast->l->offset = mte_parent_slot(mas->node); + mast->l->max = mast->bn->pivot[split]; + mast->r->min = mast->l->max + 1; + if (mte_is_leaf(mas->node)) + return; + + p_slot = mast->orig_l->offset; + mas_set_split_parent(mast->orig_l, mast->l->node, mast->r->node, + &p_slot, split); + mas_set_split_parent(mast->orig_r, mast->l->node, mast->r->node, + &p_slot, split); +} + +/* + * mas_push_data() - Instead of splitting a node, it is beneficial to push the + * data to the right or left node if there is room. + * @mas: The maple state + * @height: The current height of the maple state + * @mast: The maple subtree state + * @left: Push left or not. + * + * Keeping the height of the tree low means faster lookups. + * + * Return: True if pushed, false otherwise. + */ +static inline bool mas_push_data(struct ma_state *mas, int height, + struct maple_subtree_state *mast, bool left) +{ + unsigned char slot_total = mast->bn->b_end; + unsigned char end, space, split; + + MA_STATE(tmp_mas, mas->tree, mas->index, mas->last); + tmp_mas = *mas; + tmp_mas.depth = mast->l->depth; + + if (left && !mas_prev_sibling(&tmp_mas)) + return false; + else if (!left && !mas_next_sibling(&tmp_mas)) + return false; + + end = mas_data_end(&tmp_mas); + slot_total += end; + space = 2 * mt_slot_count(mas->node) - 2; + /* -2 instead of -1 to ensure there isn't a triple split */ + if (ma_is_leaf(mast->bn->type)) + space--; + + if (mas->max == ULONG_MAX) + space--; + + if (slot_total >= space) + return false; + + /* Get the data; Fill mast->bn */ + mast->bn->b_end++; + if (left) { + mab_shift_right(mast->bn, end + 1); + mas_mab_cp(&tmp_mas, 0, end, mast->bn, 0); + mast->bn->b_end = slot_total + 1; + } else { + mas_mab_cp(&tmp_mas, 0, end, mast->bn, mast->bn->b_end); + } + + /* Configure mast for splitting of mast->bn */ + split = mt_slots[mast->bn->type] - 2; + if (left) { + /* Switch mas to prev node */ + *mas = tmp_mas; + /* Start using mast->l for the left side. */ + tmp_mas.node = mast->l->node; + *mast->l = tmp_mas; + } else { + tmp_mas.node = mast->r->node; + *mast->r = tmp_mas; + split = slot_total - split; + } + split = mab_no_null_split(mast->bn, split, mt_slots[mast->bn->type]); + /* Update parent slot for split calculation. */ + if (left) + mast->orig_l->offset += end + 1; + + mast_split_data(mast, mas, split); + mast_fill_bnode(mast, mas, 2); + mas_split_final_node(mast, mas, height + 1); + return true; +} + +/* + * mas_split() - Split data that is too big for one node into two. + * @mas: The maple state + * @b_node: The maple big node + * Return: 1 on success, 0 on failure. + */ +static int mas_split(struct ma_state *mas, struct maple_big_node *b_node) +{ + struct maple_subtree_state mast; + int height = 0; + unsigned char mid_split, split = 0; + struct maple_enode *old; + + /* + * Splitting is handled differently from any other B-tree; the Maple + * Tree splits upwards. Splitting up means that the split operation + * occurs when the walk of the tree hits the leaves and not on the way + * down. The reason for splitting up is that it is impossible to know + * how much space will be needed until the leaf is (or leaves are) + * reached. Since overwriting data is allowed and a range could + * overwrite more than one range or result in changing one entry into 3 + * entries, it is impossible to know if a split is required until the + * data is examined. + * + * Splitting is a balancing act between keeping allocations to a minimum + * and avoiding a 'jitter' event where a tree is expanded to make room + * for an entry followed by a contraction when the entry is removed. To + * accomplish the balance, there are empty slots remaining in both left + * and right nodes after a split. + */ + MA_STATE(l_mas, mas->tree, mas->index, mas->last); + MA_STATE(r_mas, mas->tree, mas->index, mas->last); + MA_STATE(prev_l_mas, mas->tree, mas->index, mas->last); + MA_STATE(prev_r_mas, mas->tree, mas->index, mas->last); + + trace_ma_op(__func__, mas); + mas->depth = mas_mt_height(mas); + /* Allocation failures will happen early. */ + mas_node_count(mas, 1 + mas->depth * 2); + if (mas_is_err(mas)) + return 0; + + mast.l = &l_mas; + mast.r = &r_mas; + mast.orig_l = &prev_l_mas; + mast.orig_r = &prev_r_mas; + mast.bn = b_node; + + while (height++ <= mas->depth) { + if (mt_slots[b_node->type] > b_node->b_end) { + mas_split_final_node(&mast, mas, height); + break; + } + + l_mas = r_mas = *mas; + l_mas.node = mas_new_ma_node(mas, b_node); + r_mas.node = mas_new_ma_node(mas, b_node); + /* + * Another way that 'jitter' is avoided is to terminate a split up early if the + * left or right node has space to spare. This is referred to as "pushing left" + * or "pushing right" and is similar to the B* tree, except the nodes left or + * right can rarely be reused due to RCU, but the ripple upwards is halted which + * is a significant savings. + */ + /* Try to push left. */ + if (mas_push_data(mas, height, &mast, true)) + break; + /* Try to push right. */ + if (mas_push_data(mas, height, &mast, false)) + break; + + split = mab_calc_split(mas, b_node, &mid_split, prev_l_mas.min); + mast_split_data(&mast, mas, split); + /* + * Usually correct, mab_mas_cp in the above call overwrites + * r->max. + */ + mast.r->max = mas->max; + mast_fill_bnode(&mast, mas, 1); + prev_l_mas = *mast.l; + prev_r_mas = *mast.r; + } + + /* Set the original node as dead */ + old = mas->node; + mas->node = l_mas.node; + mas_wmb_replace(mas, old); + mtree_range_walk(mas); + return 1; +} + +/* + * mas_reuse_node() - Reuse the node to store the data. + * @wr_mas: The maple write state + * @bn: The maple big node + * @end: The end of the data. + * + * Will always return false in RCU mode. + * + * Return: True if node was reused, false otherwise. + */ +static inline bool mas_reuse_node(struct ma_wr_state *wr_mas, + struct maple_big_node *bn, unsigned char end) +{ + /* Need to be rcu safe. */ + if (mt_in_rcu(wr_mas->mas->tree)) + return false; + + if (end > bn->b_end) { + int clear = mt_slots[wr_mas->type] - bn->b_end; + + memset(wr_mas->slots + bn->b_end, 0, sizeof(void *) * clear--); + memset(wr_mas->pivots + bn->b_end, 0, sizeof(void *) * clear); + } + mab_mas_cp(bn, 0, bn->b_end, wr_mas->mas, false); + return true; +} + +/* + * mas_commit_b_node() - Commit the big node into the tree. + * @wr_mas: The maple write state + * @b_node: The maple big node + * @end: The end of the data. + */ +static noinline_for_kasan int mas_commit_b_node(struct ma_wr_state *wr_mas, + struct maple_big_node *b_node, unsigned char end) +{ + struct maple_node *node; + struct maple_enode *old_enode; + unsigned char b_end = b_node->b_end; + enum maple_type b_type = b_node->type; + + old_enode = wr_mas->mas->node; + if ((b_end < mt_min_slots[b_type]) && + (!mte_is_root(old_enode)) && + (mas_mt_height(wr_mas->mas) > 1)) + return mas_rebalance(wr_mas->mas, b_node); + + if (b_end >= mt_slots[b_type]) + return mas_split(wr_mas->mas, b_node); + + if (mas_reuse_node(wr_mas, b_node, end)) + goto reuse_node; + + mas_node_count(wr_mas->mas, 1); + if (mas_is_err(wr_mas->mas)) + return 0; + + node = mas_pop_node(wr_mas->mas); + node->parent = mas_mn(wr_mas->mas)->parent; + wr_mas->mas->node = mt_mk_node(node, b_type); + mab_mas_cp(b_node, 0, b_end, wr_mas->mas, false); + mas_replace_node(wr_mas->mas, old_enode); +reuse_node: + mas_update_gap(wr_mas->mas); + wr_mas->mas->end = b_end; + return 1; +} + +/* + * mas_root_expand() - Expand a root to a node + * @mas: The maple state + * @entry: The entry to store into the tree + */ +static inline int mas_root_expand(struct ma_state *mas, void *entry) +{ + void *contents = mas_root_locked(mas); + enum maple_type type = maple_leaf_64; + struct maple_node *node; + void __rcu **slots; + unsigned long *pivots; + int slot = 0; + + mas_node_count(mas, 1); + if (unlikely(mas_is_err(mas))) + return 0; + + node = mas_pop_node(mas); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + node->parent = ma_parent_ptr(mas_tree_parent(mas)); + mas->node = mt_mk_node(node, type); + mas->status = ma_active; + + if (mas->index) { + if (contents) { + rcu_assign_pointer(slots[slot], contents); + if (likely(mas->index > 1)) + slot++; + } + pivots[slot++] = mas->index - 1; + } + + rcu_assign_pointer(slots[slot], entry); + mas->offset = slot; + pivots[slot] = mas->last; + if (mas->last != ULONG_MAX) + pivots[++slot] = ULONG_MAX; + + mas->depth = 1; + mas_set_height(mas); + ma_set_meta(node, maple_leaf_64, 0, slot); + /* swap the new root into the tree */ + rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); + return slot; +} + +static inline void mas_store_root(struct ma_state *mas, void *entry) +{ + if (likely((mas->last != 0) || (mas->index != 0))) + mas_root_expand(mas, entry); + else if (((unsigned long) (entry) & 3) == 2) + mas_root_expand(mas, entry); + else { + rcu_assign_pointer(mas->tree->ma_root, entry); + mas->status = ma_start; + } +} + +/* + * mas_is_span_wr() - Check if the write needs to be treated as a write that + * spans the node. + * @mas: The maple state + * @piv: The pivot value being written + * @type: The maple node type + * @entry: The data to write + * + * Spanning writes are writes that start in one node and end in another OR if + * the write of a %NULL will cause the node to end with a %NULL. + * + * Return: True if this is a spanning write, false otherwise. + */ +static bool mas_is_span_wr(struct ma_wr_state *wr_mas) +{ + unsigned long max = wr_mas->r_max; + unsigned long last = wr_mas->mas->last; + enum maple_type type = wr_mas->type; + void *entry = wr_mas->entry; + + /* Contained in this pivot, fast path */ + if (last < max) + return false; + + if (ma_is_leaf(type)) { + max = wr_mas->mas->max; + if (last < max) + return false; + } + + if (last == max) { + /* + * The last entry of leaf node cannot be NULL unless it is the + * rightmost node (writing ULONG_MAX), otherwise it spans slots. + */ + if (entry || last == ULONG_MAX) + return false; + } + + trace_ma_write(__func__, wr_mas->mas, wr_mas->r_max, entry); + return true; +} + +static inline void mas_wr_walk_descend(struct ma_wr_state *wr_mas) +{ + wr_mas->type = mte_node_type(wr_mas->mas->node); + mas_wr_node_walk(wr_mas); + wr_mas->slots = ma_slots(wr_mas->node, wr_mas->type); +} + +static inline void mas_wr_walk_traverse(struct ma_wr_state *wr_mas) +{ + wr_mas->mas->max = wr_mas->r_max; + wr_mas->mas->min = wr_mas->r_min; + wr_mas->mas->node = wr_mas->content; + wr_mas->mas->offset = 0; + wr_mas->mas->depth++; +} +/* + * mas_wr_walk() - Walk the tree for a write. + * @wr_mas: The maple write state + * + * Uses mas_slot_locked() and does not need to worry about dead nodes. + * + * Return: True if it's contained in a node, false on spanning write. + */ +static bool mas_wr_walk(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + while (true) { + mas_wr_walk_descend(wr_mas); + if (unlikely(mas_is_span_wr(wr_mas))) + return false; + + wr_mas->content = mas_slot_locked(mas, wr_mas->slots, + mas->offset); + if (ma_is_leaf(wr_mas->type)) + return true; + + mas_wr_walk_traverse(wr_mas); + } + + return true; +} + +static bool mas_wr_walk_index(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + while (true) { + mas_wr_walk_descend(wr_mas); + wr_mas->content = mas_slot_locked(mas, wr_mas->slots, + mas->offset); + if (ma_is_leaf(wr_mas->type)) + return true; + mas_wr_walk_traverse(wr_mas); + + } + return true; +} +/* + * mas_extend_spanning_null() - Extend a store of a %NULL to include surrounding %NULLs. + * @l_wr_mas: The left maple write state + * @r_wr_mas: The right maple write state + */ +static inline void mas_extend_spanning_null(struct ma_wr_state *l_wr_mas, + struct ma_wr_state *r_wr_mas) +{ + struct ma_state *r_mas = r_wr_mas->mas; + struct ma_state *l_mas = l_wr_mas->mas; + unsigned char l_slot; + + l_slot = l_mas->offset; + if (!l_wr_mas->content) + l_mas->index = l_wr_mas->r_min; + + if ((l_mas->index == l_wr_mas->r_min) && + (l_slot && + !mas_slot_locked(l_mas, l_wr_mas->slots, l_slot - 1))) { + if (l_slot > 1) + l_mas->index = l_wr_mas->pivots[l_slot - 2] + 1; + else + l_mas->index = l_mas->min; + + l_mas->offset = l_slot - 1; + } + + if (!r_wr_mas->content) { + if (r_mas->last < r_wr_mas->r_max) + r_mas->last = r_wr_mas->r_max; + r_mas->offset++; + } else if ((r_mas->last == r_wr_mas->r_max) && + (r_mas->last < r_mas->max) && + !mas_slot_locked(r_mas, r_wr_mas->slots, r_mas->offset + 1)) { + r_mas->last = mas_safe_pivot(r_mas, r_wr_mas->pivots, + r_wr_mas->type, r_mas->offset + 1); + r_mas->offset++; + } +} + +static inline void *mas_state_walk(struct ma_state *mas) +{ + void *entry; + + entry = mas_start(mas); + if (mas_is_none(mas)) + return NULL; + + if (mas_is_ptr(mas)) + return entry; + + return mtree_range_walk(mas); +} + +/* + * mtree_lookup_walk() - Internal quick lookup that does not keep maple state up + * to date. + * + * @mas: The maple state. + * + * Note: Leaves mas in undesirable state. + * Return: The entry for @mas->index or %NULL on dead node. + */ +static inline void *mtree_lookup_walk(struct ma_state *mas) +{ + unsigned long *pivots; + unsigned char offset; + struct maple_node *node; + struct maple_enode *next; + enum maple_type type; + void __rcu **slots; + unsigned char end; + + next = mas->node; + do { + node = mte_to_node(next); + type = mte_node_type(next); + pivots = ma_pivots(node, type); + end = mt_pivots[type]; + offset = 0; + do { + if (pivots[offset] >= mas->index) + break; + } while (++offset < end); + + slots = ma_slots(node, type); + next = mt_slot(mas->tree, slots, offset); + if (unlikely(ma_dead_node(node))) + goto dead_node; + } while (!ma_is_leaf(type)); + + return (void *)next; + +dead_node: + mas_reset(mas); + return NULL; +} + +static void mte_destroy_walk(struct maple_enode *, struct maple_tree *); +/* + * mas_new_root() - Create a new root node that only contains the entry passed + * in. + * @mas: The maple state + * @entry: The entry to store. + * + * Only valid when the index == 0 and the last == ULONG_MAX + * + * Return 0 on error, 1 on success. + */ +static inline int mas_new_root(struct ma_state *mas, void *entry) +{ + struct maple_enode *root = mas_root_locked(mas); + enum maple_type type = maple_leaf_64; + struct maple_node *node; + void __rcu **slots; + unsigned long *pivots; + + if (!entry && !mas->index && mas->last == ULONG_MAX) { + mas->depth = 0; + mas_set_height(mas); + rcu_assign_pointer(mas->tree->ma_root, entry); + mas->status = ma_start; + goto done; + } + + mas_node_count(mas, 1); + if (mas_is_err(mas)) + return 0; + + node = mas_pop_node(mas); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + node->parent = ma_parent_ptr(mas_tree_parent(mas)); + mas->node = mt_mk_node(node, type); + mas->status = ma_active; + rcu_assign_pointer(slots[0], entry); + pivots[0] = mas->last; + mas->depth = 1; + mas_set_height(mas); + rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); + +done: + if (xa_is_node(root)) + mte_destroy_walk(root, mas->tree); + + return 1; +} +/* + * mas_wr_spanning_store() - Create a subtree with the store operation completed + * and new nodes where necessary, then place the sub-tree in the actual tree. + * Note that mas is expected to point to the node which caused the store to + * span. + * @wr_mas: The maple write state + * + * Return: 0 on error, positive on success. + */ +static inline int mas_wr_spanning_store(struct ma_wr_state *wr_mas) +{ + struct maple_subtree_state mast; + struct maple_big_node b_node; + struct ma_state *mas; + unsigned char height; + + /* Left and Right side of spanning store */ + MA_STATE(l_mas, NULL, 0, 0); + MA_STATE(r_mas, NULL, 0, 0); + MA_WR_STATE(r_wr_mas, &r_mas, wr_mas->entry); + MA_WR_STATE(l_wr_mas, &l_mas, wr_mas->entry); + + /* + * A store operation that spans multiple nodes is called a spanning + * store and is handled early in the store call stack by the function + * mas_is_span_wr(). When a spanning store is identified, the maple + * state is duplicated. The first maple state walks the left tree path + * to ``index``, the duplicate walks the right tree path to ``last``. + * The data in the two nodes are combined into a single node, two nodes, + * or possibly three nodes (see the 3-way split above). A ``NULL`` + * written to the last entry of a node is considered a spanning store as + * a rebalance is required for the operation to complete and an overflow + * of data may happen. + */ + mas = wr_mas->mas; + trace_ma_op(__func__, mas); + + if (unlikely(!mas->index && mas->last == ULONG_MAX)) + return mas_new_root(mas, wr_mas->entry); + /* + * Node rebalancing may occur due to this store, so there may be three new + * entries per level plus a new root. + */ + height = mas_mt_height(mas); + mas_node_count(mas, 1 + height * 3); + if (mas_is_err(mas)) + return 0; + + /* + * Set up right side. Need to get to the next offset after the spanning + * store to ensure it's not NULL and to combine both the next node and + * the node with the start together. + */ + r_mas = *mas; + /* Avoid overflow, walk to next slot in the tree. */ + if (r_mas.last + 1) + r_mas.last++; + + r_mas.index = r_mas.last; + mas_wr_walk_index(&r_wr_mas); + r_mas.last = r_mas.index = mas->last; + + /* Set up left side. */ + l_mas = *mas; + mas_wr_walk_index(&l_wr_mas); + + if (!wr_mas->entry) { + mas_extend_spanning_null(&l_wr_mas, &r_wr_mas); + mas->offset = l_mas.offset; + mas->index = l_mas.index; + mas->last = l_mas.last = r_mas.last; + } + + /* expanding NULLs may make this cover the entire range */ + if (!l_mas.index && r_mas.last == ULONG_MAX) { + mas_set_range(mas, 0, ULONG_MAX); + return mas_new_root(mas, wr_mas->entry); + } + + memset(&b_node, 0, sizeof(struct maple_big_node)); + /* Copy l_mas and store the value in b_node. */ + mas_store_b_node(&l_wr_mas, &b_node, l_mas.end); + /* Copy r_mas into b_node. */ + if (r_mas.offset <= r_mas.end) + mas_mab_cp(&r_mas, r_mas.offset, r_mas.end, + &b_node, b_node.b_end + 1); + else + b_node.b_end++; + + /* Stop spanning searches by searching for just index. */ + l_mas.index = l_mas.last = mas->index; + + mast.bn = &b_node; + mast.orig_l = &l_mas; + mast.orig_r = &r_mas; + /* Combine l_mas and r_mas and split them up evenly again. */ + return mas_spanning_rebalance(mas, &mast, height + 1); +} + +/* + * mas_wr_node_store() - Attempt to store the value in a node + * @wr_mas: The maple write state + * + * Attempts to reuse the node, but may allocate. + * + * Return: True if stored, false otherwise + */ +static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas, + unsigned char new_end) +{ + struct ma_state *mas = wr_mas->mas; + void __rcu **dst_slots; + unsigned long *dst_pivots; + unsigned char dst_offset, offset_end = wr_mas->offset_end; + struct maple_node reuse, *newnode; + unsigned char copy_size, node_pivots = mt_pivots[wr_mas->type]; + bool in_rcu = mt_in_rcu(mas->tree); + + /* Check if there is enough data. The room is enough. */ + if (!mte_is_root(mas->node) && (new_end <= mt_min_slots[wr_mas->type]) && + !(mas->mas_flags & MA_STATE_BULK)) + return false; + + if (mas->last == wr_mas->end_piv) + offset_end++; /* don't copy this offset */ + else if (unlikely(wr_mas->r_max == ULONG_MAX)) + mas_bulk_rebalance(mas, mas->end, wr_mas->type); + + /* set up node. */ + if (in_rcu) { + mas_node_count(mas, 1); + if (mas_is_err(mas)) + return false; + + newnode = mas_pop_node(mas); + } else { + memset(&reuse, 0, sizeof(struct maple_node)); + newnode = &reuse; + } + + newnode->parent = mas_mn(mas)->parent; + dst_pivots = ma_pivots(newnode, wr_mas->type); + dst_slots = ma_slots(newnode, wr_mas->type); + /* Copy from start to insert point */ + memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * mas->offset); + memcpy(dst_slots, wr_mas->slots, sizeof(void *) * mas->offset); + + /* Handle insert of new range starting after old range */ + if (wr_mas->r_min < mas->index) { + rcu_assign_pointer(dst_slots[mas->offset], wr_mas->content); + dst_pivots[mas->offset++] = mas->index - 1; + } + + /* Store the new entry and range end. */ + if (mas->offset < node_pivots) + dst_pivots[mas->offset] = mas->last; + rcu_assign_pointer(dst_slots[mas->offset], wr_mas->entry); + + /* + * this range wrote to the end of the node or it overwrote the rest of + * the data + */ + if (offset_end > mas->end) + goto done; + + dst_offset = mas->offset + 1; + /* Copy to the end of node if necessary. */ + copy_size = mas->end - offset_end + 1; + memcpy(dst_slots + dst_offset, wr_mas->slots + offset_end, + sizeof(void *) * copy_size); + memcpy(dst_pivots + dst_offset, wr_mas->pivots + offset_end, + sizeof(unsigned long) * (copy_size - 1)); + + if (new_end < node_pivots) + dst_pivots[new_end] = mas->max; + +done: + mas_leaf_set_meta(newnode, maple_leaf_64, new_end); + if (in_rcu) { + struct maple_enode *old_enode = mas->node; + + mas->node = mt_mk_node(newnode, wr_mas->type); + mas_replace_node(mas, old_enode); + } else { + memcpy(wr_mas->node, newnode, sizeof(struct maple_node)); + } + trace_ma_write(__func__, mas, 0, wr_mas->entry); + mas_update_gap(mas); + mas->end = new_end; + return true; +} + +/* + * mas_wr_slot_store: Attempt to store a value in a slot. + * @wr_mas: the maple write state + * + * Return: True if stored, false otherwise + */ +static inline bool mas_wr_slot_store(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + unsigned char offset = mas->offset; + void __rcu **slots = wr_mas->slots; + bool gap = false; + + gap |= !mt_slot_locked(mas->tree, slots, offset); + gap |= !mt_slot_locked(mas->tree, slots, offset + 1); + + if (wr_mas->offset_end - offset == 1) { + if (mas->index == wr_mas->r_min) { + /* Overwriting the range and a part of the next one */ + rcu_assign_pointer(slots[offset], wr_mas->entry); + wr_mas->pivots[offset] = mas->last; + } else { + /* Overwriting a part of the range and the next one */ + rcu_assign_pointer(slots[offset + 1], wr_mas->entry); + wr_mas->pivots[offset] = mas->index - 1; + mas->offset++; /* Keep mas accurate. */ + } + } else if (!mt_in_rcu(mas->tree)) { + /* + * Expand the range, only partially overwriting the previous and + * next ranges + */ + gap |= !mt_slot_locked(mas->tree, slots, offset + 2); + rcu_assign_pointer(slots[offset + 1], wr_mas->entry); + wr_mas->pivots[offset] = mas->index - 1; + wr_mas->pivots[offset + 1] = mas->last; + mas->offset++; /* Keep mas accurate. */ + } else { + return false; + } + + trace_ma_write(__func__, mas, 0, wr_mas->entry); + /* + * Only update gap when the new entry is empty or there is an empty + * entry in the original two ranges. + */ + if (!wr_mas->entry || gap) + mas_update_gap(mas); + + return true; +} + +static inline void mas_wr_extend_null(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + if (!wr_mas->slots[wr_mas->offset_end]) { + /* If this one is null, the next and prev are not */ + mas->last = wr_mas->end_piv; + } else { + /* Check next slot(s) if we are overwriting the end */ + if ((mas->last == wr_mas->end_piv) && + (mas->end != wr_mas->offset_end) && + !wr_mas->slots[wr_mas->offset_end + 1]) { + wr_mas->offset_end++; + if (wr_mas->offset_end == mas->end) + mas->last = mas->max; + else + mas->last = wr_mas->pivots[wr_mas->offset_end]; + wr_mas->end_piv = mas->last; + } + } + + if (!wr_mas->content) { + /* If this one is null, the next and prev are not */ + mas->index = wr_mas->r_min; + } else { + /* Check prev slot if we are overwriting the start */ + if (mas->index == wr_mas->r_min && mas->offset && + !wr_mas->slots[mas->offset - 1]) { + mas->offset--; + wr_mas->r_min = mas->index = + mas_safe_min(mas, wr_mas->pivots, mas->offset); + wr_mas->r_max = wr_mas->pivots[mas->offset]; + } + } +} + +static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas) +{ + while ((wr_mas->offset_end < wr_mas->mas->end) && + (wr_mas->mas->last > wr_mas->pivots[wr_mas->offset_end])) + wr_mas->offset_end++; + + if (wr_mas->offset_end < wr_mas->mas->end) + wr_mas->end_piv = wr_mas->pivots[wr_mas->offset_end]; + else + wr_mas->end_piv = wr_mas->mas->max; + + if (!wr_mas->entry) + mas_wr_extend_null(wr_mas); +} + +static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + unsigned char new_end = mas->end + 2; + + new_end -= wr_mas->offset_end - mas->offset; + if (wr_mas->r_min == mas->index) + new_end--; + + if (wr_mas->end_piv == mas->last) + new_end--; + + return new_end; +} + +/* + * mas_wr_append: Attempt to append + * @wr_mas: the maple write state + * @new_end: The end of the node after the modification + * + * This is currently unsafe in rcu mode since the end of the node may be cached + * by readers while the node contents may be updated which could result in + * inaccurate information. + * + * Return: True if appended, false otherwise + */ +static inline bool mas_wr_append(struct ma_wr_state *wr_mas, + unsigned char new_end) +{ + struct ma_state *mas; + void __rcu **slots; + unsigned char end; + + mas = wr_mas->mas; + if (mt_in_rcu(mas->tree)) + return false; + + end = mas->end; + if (mas->offset != end) + return false; + + if (new_end < mt_pivots[wr_mas->type]) { + wr_mas->pivots[new_end] = wr_mas->pivots[end]; + ma_set_meta(wr_mas->node, wr_mas->type, 0, new_end); + } + + slots = wr_mas->slots; + if (new_end == end + 1) { + if (mas->last == wr_mas->r_max) { + /* Append to end of range */ + rcu_assign_pointer(slots[new_end], wr_mas->entry); + wr_mas->pivots[end] = mas->index - 1; + mas->offset = new_end; + } else { + /* Append to start of range */ + rcu_assign_pointer(slots[new_end], wr_mas->content); + wr_mas->pivots[end] = mas->last; + rcu_assign_pointer(slots[end], wr_mas->entry); + } + } else { + /* Append to the range without touching any boundaries. */ + rcu_assign_pointer(slots[new_end], wr_mas->content); + wr_mas->pivots[end + 1] = mas->last; + rcu_assign_pointer(slots[end + 1], wr_mas->entry); + wr_mas->pivots[end] = mas->index - 1; + mas->offset = end + 1; + } + + if (!wr_mas->content || !wr_mas->entry) + mas_update_gap(mas); + + mas->end = new_end; + trace_ma_write(__func__, mas, new_end, wr_mas->entry); + return true; +} + +/* + * mas_wr_bnode() - Slow path for a modification. + * @wr_mas: The write maple state + * + * This is where split, rebalance end up. + */ +static void mas_wr_bnode(struct ma_wr_state *wr_mas) +{ + struct maple_big_node b_node; + + trace_ma_write(__func__, wr_mas->mas, 0, wr_mas->entry); + memset(&b_node, 0, sizeof(struct maple_big_node)); + mas_store_b_node(wr_mas, &b_node, wr_mas->offset_end); + mas_commit_b_node(wr_mas, &b_node, wr_mas->mas->end); +} + +static inline void mas_wr_modify(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + unsigned char new_end; + + /* Direct replacement */ + if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) { + rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry); + if (!!wr_mas->entry ^ !!wr_mas->content) + mas_update_gap(mas); + return; + } + + /* + * new_end exceeds the size of the maple node and cannot enter the fast + * path. + */ + new_end = mas_wr_new_end(wr_mas); + if (new_end >= mt_slots[wr_mas->type]) + goto slow_path; + + /* Attempt to append */ + if (mas_wr_append(wr_mas, new_end)) + return; + + if (new_end == mas->end && mas_wr_slot_store(wr_mas)) + return; + + if (mas_wr_node_store(wr_mas, new_end)) + return; + + if (mas_is_err(mas)) + return; + +slow_path: + mas_wr_bnode(wr_mas); +} + +/* + * mas_wr_store_entry() - Internal call to store a value + * @mas: The maple state + * @entry: The entry to store. + * + * Return: The contents that was stored at the index. + */ +static inline void *mas_wr_store_entry(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + wr_mas->content = mas_start(mas); + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_store_root(mas, wr_mas->entry); + return wr_mas->content; + } + + if (unlikely(!mas_wr_walk(wr_mas))) { + mas_wr_spanning_store(wr_mas); + return wr_mas->content; + } + + /* At this point, we are at the leaf node that needs to be altered. */ + mas_wr_end_piv(wr_mas); + /* New root for a single pointer */ + if (unlikely(!mas->index && mas->last == ULONG_MAX)) { + mas_new_root(mas, wr_mas->entry); + return wr_mas->content; + } + + mas_wr_modify(wr_mas); + return wr_mas->content; +} + +/** + * mas_insert() - Internal call to insert a value + * @mas: The maple state + * @entry: The entry to store + * + * Return: %NULL or the contents that already exists at the requested index + * otherwise. The maple state needs to be checked for error conditions. + */ +static inline void *mas_insert(struct ma_state *mas, void *entry) +{ + MA_WR_STATE(wr_mas, mas, entry); + + /* + * Inserting a new range inserts either 0, 1, or 2 pivots within the + * tree. If the insert fits exactly into an existing gap with a value + * of NULL, then the slot only needs to be written with the new value. + * If the range being inserted is adjacent to another range, then only a + * single pivot needs to be inserted (as well as writing the entry). If + * the new range is within a gap but does not touch any other ranges, + * then two pivots need to be inserted: the start - 1, and the end. As + * usual, the entry must be written. Most operations require a new node + * to be allocated and replace an existing node to ensure RCU safety, + * when in RCU mode. The exception to requiring a newly allocated node + * is when inserting at the end of a node (appending). When done + * carefully, appending can reuse the node in place. + */ + wr_mas.content = mas_start(mas); + if (wr_mas.content) + goto exists; + + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_store_root(mas, entry); + return NULL; + } + + /* spanning writes always overwrite something */ + if (!mas_wr_walk(&wr_mas)) + goto exists; + + /* At this point, we are at the leaf node that needs to be altered. */ + wr_mas.offset_end = mas->offset; + wr_mas.end_piv = wr_mas.r_max; + + if (wr_mas.content || (mas->last > wr_mas.r_max)) + goto exists; + + if (!entry) + return NULL; + + mas_wr_modify(&wr_mas); + return wr_mas.content; + +exists: + mas_set_err(mas, -EEXIST); + return wr_mas.content; + +} + +static __always_inline void mas_rewalk(struct ma_state *mas, unsigned long index) +{ +retry: + mas_set(mas, index); + mas_state_walk(mas); + if (mas_is_start(mas)) + goto retry; +} + +static __always_inline bool mas_rewalk_if_dead(struct ma_state *mas, + struct maple_node *node, const unsigned long index) +{ + if (unlikely(ma_dead_node(node))) { + mas_rewalk(mas, index); + return true; + } + return false; +} + +/* + * mas_prev_node() - Find the prev non-null entry at the same level in the + * tree. The prev value will be mas->node[mas->offset] or the status will be + * ma_none. + * @mas: The maple state + * @min: The lower limit to search + * + * The prev node value will be mas->node[mas->offset] or the status will be + * ma_none. + * Return: 1 if the node is dead, 0 otherwise. + */ +static int mas_prev_node(struct ma_state *mas, unsigned long min) +{ + enum maple_type mt; + int offset, level; + void __rcu **slots; + struct maple_node *node; + unsigned long *pivots; + unsigned long max; + + node = mas_mn(mas); + if (!mas->min) + goto no_entry; + + max = mas->min - 1; + if (max < min) + goto no_entry; + + level = 0; + do { + if (ma_is_root(node)) + goto no_entry; + + /* Walk up. */ + if (unlikely(mas_ascend(mas))) + return 1; + offset = mas->offset; + level++; + node = mas_mn(mas); + } while (!offset); + + offset--; + mt = mte_node_type(mas->node); + while (level > 1) { + level--; + slots = ma_slots(node, mt); + mas->node = mas_slot(mas, slots, offset); + if (unlikely(ma_dead_node(node))) + return 1; + + mt = mte_node_type(mas->node); + node = mas_mn(mas); + pivots = ma_pivots(node, mt); + offset = ma_data_end(node, mt, pivots, max); + if (unlikely(ma_dead_node(node))) + return 1; + } + + slots = ma_slots(node, mt); + mas->node = mas_slot(mas, slots, offset); + pivots = ma_pivots(node, mt); + if (unlikely(ma_dead_node(node))) + return 1; + + if (likely(offset)) + mas->min = pivots[offset - 1] + 1; + mas->max = max; + mas->offset = mas_data_end(mas); + if (unlikely(mte_dead_node(mas->node))) + return 1; + + mas->end = mas->offset; + return 0; + +no_entry: + if (unlikely(ma_dead_node(node))) + return 1; + + mas->status = ma_underflow; + return 0; +} + +/* + * mas_prev_slot() - Get the entry in the previous slot + * + * @mas: The maple state + * @max: The minimum starting range + * @empty: Can be empty + * @set_underflow: Set the @mas->node to underflow state on limit. + * + * Return: The entry in the previous slot which is possibly NULL + */ +static void *mas_prev_slot(struct ma_state *mas, unsigned long min, bool empty) +{ + void *entry; + void __rcu **slots; + unsigned long pivot; + enum maple_type type; + unsigned long *pivots; + struct maple_node *node; + unsigned long save_point = mas->index; + +retry: + node = mas_mn(mas); + type = mte_node_type(mas->node); + pivots = ma_pivots(node, type); + if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) + goto retry; + + if (mas->min <= min) { + pivot = mas_safe_min(mas, pivots, mas->offset); + + if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) + goto retry; + + if (pivot <= min) + goto underflow; + } + +again: + if (likely(mas->offset)) { + mas->offset--; + mas->last = mas->index - 1; + mas->index = mas_safe_min(mas, pivots, mas->offset); + } else { + if (mas->index <= min) + goto underflow; + + if (mas_prev_node(mas, min)) { + mas_rewalk(mas, save_point); + goto retry; + } + + if (WARN_ON_ONCE(mas_is_underflow(mas))) + return NULL; + + mas->last = mas->max; + node = mas_mn(mas); + type = mte_node_type(mas->node); + pivots = ma_pivots(node, type); + mas->index = pivots[mas->offset - 1] + 1; + } + + slots = ma_slots(node, type); + entry = mas_slot(mas, slots, mas->offset); + if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) + goto retry; + + + if (likely(entry)) + return entry; + + if (!empty) { + if (mas->index <= min) { + mas->status = ma_underflow; + return NULL; + } + + goto again; + } + + return entry; + +underflow: + mas->status = ma_underflow; + return NULL; +} + +/* + * mas_next_node() - Get the next node at the same level in the tree. + * @mas: The maple state + * @max: The maximum pivot value to check. + * + * The next value will be mas->node[mas->offset] or the status will have + * overflowed. + * Return: 1 on dead node, 0 otherwise. + */ +static int mas_next_node(struct ma_state *mas, struct maple_node *node, + unsigned long max) +{ + unsigned long min; + unsigned long *pivots; + struct maple_enode *enode; + struct maple_node *tmp; + int level = 0; + unsigned char node_end; + enum maple_type mt; + void __rcu **slots; + + if (mas->max >= max) + goto overflow; + + min = mas->max + 1; + level = 0; + do { + if (ma_is_root(node)) + goto overflow; + + /* Walk up. */ + if (unlikely(mas_ascend(mas))) + return 1; + + level++; + node = mas_mn(mas); + mt = mte_node_type(mas->node); + pivots = ma_pivots(node, mt); + node_end = ma_data_end(node, mt, pivots, mas->max); + if (unlikely(ma_dead_node(node))) + return 1; + + } while (unlikely(mas->offset == node_end)); + + slots = ma_slots(node, mt); + mas->offset++; + enode = mas_slot(mas, slots, mas->offset); + if (unlikely(ma_dead_node(node))) + return 1; + + if (level > 1) + mas->offset = 0; + + while (unlikely(level > 1)) { + level--; + mas->node = enode; + node = mas_mn(mas); + mt = mte_node_type(mas->node); + slots = ma_slots(node, mt); + enode = mas_slot(mas, slots, 0); + if (unlikely(ma_dead_node(node))) + return 1; + } + + if (!mas->offset) + pivots = ma_pivots(node, mt); + + mas->max = mas_safe_pivot(mas, pivots, mas->offset, mt); + tmp = mte_to_node(enode); + mt = mte_node_type(enode); + pivots = ma_pivots(tmp, mt); + mas->end = ma_data_end(tmp, mt, pivots, mas->max); + if (unlikely(ma_dead_node(node))) + return 1; + + mas->node = enode; + mas->min = min; + return 0; + +overflow: + if (unlikely(ma_dead_node(node))) + return 1; + + mas->status = ma_overflow; + return 0; +} + +/* + * mas_next_slot() - Get the entry in the next slot + * + * @mas: The maple state + * @max: The maximum starting range + * @empty: Can be empty + * @set_overflow: Should @mas->node be set to overflow when the limit is + * reached. + * + * Return: The entry in the next slot which is possibly NULL + */ +static void *mas_next_slot(struct ma_state *mas, unsigned long max, bool empty) +{ + void __rcu **slots; + unsigned long *pivots; + unsigned long pivot; + enum maple_type type; + struct maple_node *node; + unsigned long save_point = mas->last; + void *entry; + +retry: + node = mas_mn(mas); + type = mte_node_type(mas->node); + pivots = ma_pivots(node, type); + if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) + goto retry; + + if (mas->max >= max) { + if (likely(mas->offset < mas->end)) + pivot = pivots[mas->offset]; + else + pivot = mas->max; + + if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) + goto retry; + + if (pivot >= max) { /* Was at the limit, next will extend beyond */ + mas->status = ma_overflow; + return NULL; + } + } + + if (likely(mas->offset < mas->end)) { + mas->index = pivots[mas->offset] + 1; +again: + mas->offset++; + if (likely(mas->offset < mas->end)) + mas->last = pivots[mas->offset]; + else + mas->last = mas->max; + } else { + if (mas->last >= max) { + mas->status = ma_overflow; + return NULL; + } + + if (mas_next_node(mas, node, max)) { + mas_rewalk(mas, save_point); + goto retry; + } + + if (WARN_ON_ONCE(mas_is_overflow(mas))) + return NULL; + + mas->offset = 0; + mas->index = mas->min; + node = mas_mn(mas); + type = mte_node_type(mas->node); + pivots = ma_pivots(node, type); + mas->last = pivots[0]; + } + + slots = ma_slots(node, type); + entry = mt_slot(mas->tree, slots, mas->offset); + if (unlikely(mas_rewalk_if_dead(mas, node, save_point))) + goto retry; + + if (entry) + return entry; + + + if (!empty) { + if (mas->last >= max) { + mas->status = ma_overflow; + return NULL; + } + + mas->index = mas->last + 1; + goto again; + } + + return entry; +} + +/* + * mas_next_entry() - Internal function to get the next entry. + * @mas: The maple state + * @limit: The maximum range start. + * + * Set the @mas->node to the next entry and the range_start to + * the beginning value for the entry. Does not check beyond @limit. + * Sets @mas->index and @mas->last to the range, Does not update @mas->index and + * @mas->last on overflow. + * Restarts on dead nodes. + * + * Return: the next entry or %NULL. + */ +static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit) +{ + if (mas->last >= limit) { + mas->status = ma_overflow; + return NULL; + } + + return mas_next_slot(mas, limit, false); +} + +/* + * mas_rev_awalk() - Internal function. Reverse allocation walk. Find the + * highest gap address of a given size in a given node and descend. + * @mas: The maple state + * @size: The needed size. + * + * Return: True if found in a leaf, false otherwise. + * + */ +static bool mas_rev_awalk(struct ma_state *mas, unsigned long size, + unsigned long *gap_min, unsigned long *gap_max) +{ + enum maple_type type = mte_node_type(mas->node); + struct maple_node *node = mas_mn(mas); + unsigned long *pivots, *gaps; + void __rcu **slots; + unsigned long gap = 0; + unsigned long max, min; + unsigned char offset; + + if (unlikely(mas_is_err(mas))) + return true; + + if (ma_is_dense(type)) { + /* dense nodes. */ + mas->offset = (unsigned char)(mas->index - mas->min); + return true; + } + + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + gaps = ma_gaps(node, type); + offset = mas->offset; + min = mas_safe_min(mas, pivots, offset); + /* Skip out of bounds. */ + while (mas->last < min) + min = mas_safe_min(mas, pivots, --offset); + + max = mas_safe_pivot(mas, pivots, offset, type); + while (mas->index <= max) { + gap = 0; + if (gaps) + gap = gaps[offset]; + else if (!mas_slot(mas, slots, offset)) + gap = max - min + 1; + + if (gap) { + if ((size <= gap) && (size <= mas->last - min + 1)) + break; + + if (!gaps) { + /* Skip the next slot, it cannot be a gap. */ + if (offset < 2) + goto ascend; + + offset -= 2; + max = pivots[offset]; + min = mas_safe_min(mas, pivots, offset); + continue; + } + } + + if (!offset) + goto ascend; + + offset--; + max = min - 1; + min = mas_safe_min(mas, pivots, offset); + } + + if (unlikely((mas->index > max) || (size - 1 > max - mas->index))) + goto no_space; + + if (unlikely(ma_is_leaf(type))) { + mas->offset = offset; + *gap_min = min; + *gap_max = min + gap - 1; + return true; + } + + /* descend, only happens under lock. */ + mas->node = mas_slot(mas, slots, offset); + mas->min = min; + mas->max = max; + mas->offset = mas_data_end(mas); + return false; + +ascend: + if (!mte_is_root(mas->node)) + return false; + +no_space: + mas_set_err(mas, -EBUSY); + return false; +} + +static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size) +{ + enum maple_type type = mte_node_type(mas->node); + unsigned long pivot, min, gap = 0; + unsigned char offset, data_end; + unsigned long *gaps, *pivots; + void __rcu **slots; + struct maple_node *node; + bool found = false; + + if (ma_is_dense(type)) { + mas->offset = (unsigned char)(mas->index - mas->min); + return true; + } + + node = mas_mn(mas); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + gaps = ma_gaps(node, type); + offset = mas->offset; + min = mas_safe_min(mas, pivots, offset); + data_end = ma_data_end(node, type, pivots, mas->max); + for (; offset <= data_end; offset++) { + pivot = mas_safe_pivot(mas, pivots, offset, type); + + /* Not within lower bounds */ + if (mas->index > pivot) + goto next_slot; + + if (gaps) + gap = gaps[offset]; + else if (!mas_slot(mas, slots, offset)) + gap = min(pivot, mas->last) - max(mas->index, min) + 1; + else + goto next_slot; + + if (gap >= size) { + if (ma_is_leaf(type)) { + found = true; + goto done; + } + if (mas->index <= pivot) { + mas->node = mas_slot(mas, slots, offset); + mas->min = min; + mas->max = pivot; + offset = 0; + break; + } + } +next_slot: + min = pivot + 1; + if (mas->last <= pivot) { + mas_set_err(mas, -EBUSY); + return true; + } + } + + if (mte_is_root(mas->node)) + found = true; +done: + mas->offset = offset; + return found; +} + +/** + * mas_walk() - Search for @mas->index in the tree. + * @mas: The maple state. + * + * mas->index and mas->last will be set to the range if there is a value. If + * mas->status is ma_none, reset to ma_start + * + * Return: the entry at the location or %NULL. + */ +void *mas_walk(struct ma_state *mas) +{ + void *entry; + + if (!mas_is_active(mas) || !mas_is_start(mas)) + mas->status = ma_start; +retry: + entry = mas_state_walk(mas); + if (mas_is_start(mas)) { + goto retry; + } else if (mas_is_none(mas)) { + mas->index = 0; + mas->last = ULONG_MAX; + } else if (mas_is_ptr(mas)) { + if (!mas->index) { + mas->last = 0; + return entry; + } + + mas->index = 1; + mas->last = ULONG_MAX; + mas->status = ma_none; + return NULL; + } + + return entry; +} +EXPORT_SYMBOL_GPL(mas_walk); + +static inline bool mas_rewind_node(struct ma_state *mas) +{ + unsigned char slot; + + do { + if (mte_is_root(mas->node)) { + slot = mas->offset; + if (!slot) + return false; + } else { + mas_ascend(mas); + slot = mas->offset; + } + } while (!slot); + + mas->offset = --slot; + return true; +} + +/* + * mas_skip_node() - Internal function. Skip over a node. + * @mas: The maple state. + * + * Return: true if there is another node, false otherwise. + */ +static inline bool mas_skip_node(struct ma_state *mas) +{ + if (mas_is_err(mas)) + return false; + + do { + if (mte_is_root(mas->node)) { + if (mas->offset >= mas_data_end(mas)) { + mas_set_err(mas, -EBUSY); + return false; + } + } else { + mas_ascend(mas); + } + } while (mas->offset >= mas_data_end(mas)); + + mas->offset++; + return true; +} + +/* + * mas_awalk() - Allocation walk. Search from low address to high, for a gap of + * @size + * @mas: The maple state + * @size: The size of the gap required + * + * Search between @mas->index and @mas->last for a gap of @size. + */ +static inline void mas_awalk(struct ma_state *mas, unsigned long size) +{ + struct maple_enode *last = NULL; + + /* + * There are 4 options: + * go to child (descend) + * go back to parent (ascend) + * no gap found. (return, slot == MAPLE_NODE_SLOTS) + * found the gap. (return, slot != MAPLE_NODE_SLOTS) + */ + while (!mas_is_err(mas) && !mas_anode_descend(mas, size)) { + if (last == mas->node) + mas_skip_node(mas); + else + last = mas->node; + } +} + +/* + * mas_sparse_area() - Internal function. Return upper or lower limit when + * searching for a gap in an empty tree. + * @mas: The maple state + * @min: the minimum range + * @max: The maximum range + * @size: The size of the gap + * @fwd: Searching forward or back + */ +static inline int mas_sparse_area(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size, bool fwd) +{ + if (!unlikely(mas_is_none(mas)) && min == 0) { + min++; + /* + * At this time, min is increased, we need to recheck whether + * the size is satisfied. + */ + if (min > max || max - min + 1 < size) + return -EBUSY; + } + /* mas_is_ptr */ + + if (fwd) { + mas->index = min; + mas->last = min + size - 1; + } else { + mas->last = max; + mas->index = max - size + 1; + } + return 0; +} + +/* + * mas_empty_area() - Get the lowest address within the range that is + * sufficient for the size requested. + * @mas: The maple state + * @min: The lowest value of the range + * @max: The highest value of the range + * @size: The size needed + */ +int mas_empty_area(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size) +{ + unsigned char offset; + unsigned long *pivots; + enum maple_type mt; + struct maple_node *node; + + if (min > max) + return -EINVAL; + + if (size == 0 || max - min < size - 1) + return -EINVAL; + + if (mas_is_start(mas)) + mas_start(mas); + else if (mas->offset >= 2) + mas->offset -= 2; + else if (!mas_skip_node(mas)) + return -EBUSY; + + /* Empty set */ + if (mas_is_none(mas) || mas_is_ptr(mas)) + return mas_sparse_area(mas, min, max, size, true); + + /* The start of the window can only be within these values */ + mas->index = min; + mas->last = max; + mas_awalk(mas, size); + + if (unlikely(mas_is_err(mas))) + return xa_err(mas->node); + + offset = mas->offset; + if (unlikely(offset == MAPLE_NODE_SLOTS)) + return -EBUSY; + + node = mas_mn(mas); + mt = mte_node_type(mas->node); + pivots = ma_pivots(node, mt); + min = mas_safe_min(mas, pivots, offset); + if (mas->index < min) + mas->index = min; + mas->last = mas->index + size - 1; + mas->end = ma_data_end(node, mt, pivots, mas->max); + return 0; +} +EXPORT_SYMBOL_GPL(mas_empty_area); + +/* + * mas_empty_area_rev() - Get the highest address within the range that is + * sufficient for the size requested. + * @mas: The maple state + * @min: The lowest value of the range + * @max: The highest value of the range + * @size: The size needed + */ +int mas_empty_area_rev(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size) +{ + struct maple_enode *last = mas->node; + + if (min > max) + return -EINVAL; + + if (size == 0 || max - min < size - 1) + return -EINVAL; + + if (mas_is_start(mas)) { + mas_start(mas); + mas->offset = mas_data_end(mas); + } else if (mas->offset >= 2) { + mas->offset -= 2; + } else if (!mas_rewind_node(mas)) { + return -EBUSY; + } + + /* Empty set. */ + if (mas_is_none(mas) || mas_is_ptr(mas)) + return mas_sparse_area(mas, min, max, size, false); + + /* The start of the window can only be within these values. */ + mas->index = min; + mas->last = max; + + while (!mas_rev_awalk(mas, size, &min, &max)) { + if (last == mas->node) { + if (!mas_rewind_node(mas)) + return -EBUSY; + } else { + last = mas->node; + } + } + + if (mas_is_err(mas)) + return xa_err(mas->node); + + if (unlikely(mas->offset == MAPLE_NODE_SLOTS)) + return -EBUSY; + + /* Trim the upper limit to the max. */ + if (max < mas->last) + mas->last = max; + + mas->index = mas->last - size + 1; + mas->end = mas_data_end(mas); + return 0; +} +EXPORT_SYMBOL_GPL(mas_empty_area_rev); + +/* + * mte_dead_leaves() - Mark all leaves of a node as dead. + * @mas: The maple state + * @slots: Pointer to the slot array + * @type: The maple node type + * + * Must hold the write lock. + * + * Return: The number of leaves marked as dead. + */ +static inline +unsigned char mte_dead_leaves(struct maple_enode *enode, struct maple_tree *mt, + void __rcu **slots) +{ + struct maple_node *node; + enum maple_type type; + void *entry; + int offset; + + for (offset = 0; offset < mt_slot_count(enode); offset++) { + entry = mt_slot(mt, slots, offset); + type = mte_node_type(entry); + node = mte_to_node(entry); + /* Use both node and type to catch LE & BE metadata */ + if (!node || !type) + break; + + mte_set_node_dead(entry); + node->type = type; + rcu_assign_pointer(slots[offset], node); + } + + return offset; +} + +/** + * mte_dead_walk() - Walk down a dead tree to just before the leaves + * @enode: The maple encoded node + * @offset: The starting offset + * + * Note: This can only be used from the RCU callback context. + */ +static void __rcu **mte_dead_walk(struct maple_enode **enode, unsigned char offset) +{ + struct maple_node *node, *next; + void __rcu **slots = NULL; + + next = mte_to_node(*enode); + do { + *enode = ma_enode_ptr(next); + node = mte_to_node(*enode); + slots = ma_slots(node, node->type); + next = rcu_dereference_protected(slots[offset], + lock_is_held(&rcu_callback_map)); + offset = 0; + } while (!ma_is_leaf(next->type)); + + return slots; +} + +/** + * mt_free_walk() - Walk & free a tree in the RCU callback context + * @head: The RCU head that's within the node. + * + * Note: This can only be used from the RCU callback context. + */ +static void mt_free_walk(struct rcu_head *head) +{ + void __rcu **slots; + struct maple_node *node, *start; + struct maple_enode *enode; + unsigned char offset; + enum maple_type type; + + node = container_of(head, struct maple_node, rcu); + + if (ma_is_leaf(node->type)) + goto free_leaf; + + start = node; + enode = mt_mk_node(node, node->type); + slots = mte_dead_walk(&enode, 0); + node = mte_to_node(enode); + do { + mt_free_bulk(node->slot_len, slots); + offset = node->parent_slot + 1; + enode = node->piv_parent; + if (mte_to_node(enode) == node) + goto free_leaf; + + type = mte_node_type(enode); + slots = ma_slots(mte_to_node(enode), type); + if ((offset < mt_slots[type]) && + rcu_dereference_protected(slots[offset], + lock_is_held(&rcu_callback_map))) + slots = mte_dead_walk(&enode, offset); + node = mte_to_node(enode); + } while ((node != start) || (node->slot_len < offset)); + + slots = ma_slots(node, node->type); + mt_free_bulk(node->slot_len, slots); + +free_leaf: + mt_free_rcu(&node->rcu); +} + +static inline void __rcu **mte_destroy_descend(struct maple_enode **enode, + struct maple_tree *mt, struct maple_enode *prev, unsigned char offset) +{ + struct maple_node *node; + struct maple_enode *next = *enode; + void __rcu **slots = NULL; + enum maple_type type; + unsigned char next_offset = 0; + + do { + *enode = next; + node = mte_to_node(*enode); + type = mte_node_type(*enode); + slots = ma_slots(node, type); + next = mt_slot_locked(mt, slots, next_offset); + if ((mte_dead_node(next))) + next = mt_slot_locked(mt, slots, ++next_offset); + + mte_set_node_dead(*enode); + node->type = type; + node->piv_parent = prev; + node->parent_slot = offset; + offset = next_offset; + next_offset = 0; + prev = *enode; + } while (!mte_is_leaf(next)); + + return slots; +} + +static void mt_destroy_walk(struct maple_enode *enode, struct maple_tree *mt, + bool free) +{ + void __rcu **slots; + struct maple_node *node = mte_to_node(enode); + struct maple_enode *start; + + if (mte_is_leaf(enode)) { + node->type = mte_node_type(enode); + goto free_leaf; + } + + start = enode; + slots = mte_destroy_descend(&enode, mt, start, 0); + node = mte_to_node(enode); // Updated in the above call. + do { + enum maple_type type; + unsigned char offset; + struct maple_enode *parent, *tmp; + + node->slot_len = mte_dead_leaves(enode, mt, slots); + if (free) + mt_free_bulk(node->slot_len, slots); + offset = node->parent_slot + 1; + enode = node->piv_parent; + if (mte_to_node(enode) == node) + goto free_leaf; + + type = mte_node_type(enode); + slots = ma_slots(mte_to_node(enode), type); + if (offset >= mt_slots[type]) + goto next; + + tmp = mt_slot_locked(mt, slots, offset); + if (mte_node_type(tmp) && mte_to_node(tmp)) { + parent = enode; + enode = tmp; + slots = mte_destroy_descend(&enode, mt, parent, offset); + } +next: + node = mte_to_node(enode); + } while (start != enode); + + node = mte_to_node(enode); + node->slot_len = mte_dead_leaves(enode, mt, slots); + if (free) + mt_free_bulk(node->slot_len, slots); + +free_leaf: + if (free) + mt_free_rcu(&node->rcu); + else + mt_clear_meta(mt, node, node->type); +} + +/* + * mte_destroy_walk() - Free a tree or sub-tree. + * @enode: the encoded maple node (maple_enode) to start + * @mt: the tree to free - needed for node types. + * + * Must hold the write lock. + */ +static inline void mte_destroy_walk(struct maple_enode *enode, + struct maple_tree *mt) +{ + struct maple_node *node = mte_to_node(enode); + + if (mt_in_rcu(mt)) { + mt_destroy_walk(enode, mt, false); + call_rcu(&node->rcu, mt_free_walk); + } else { + mt_destroy_walk(enode, mt, true); + } +} + +static void mas_wr_store_setup(struct ma_wr_state *wr_mas) +{ + if (!mas_is_active(wr_mas->mas)) { + if (mas_is_start(wr_mas->mas)) + return; + + if (unlikely(mas_is_paused(wr_mas->mas))) + goto reset; + + if (unlikely(mas_is_none(wr_mas->mas))) + goto reset; + + if (unlikely(mas_is_overflow(wr_mas->mas))) + goto reset; + + if (unlikely(mas_is_underflow(wr_mas->mas))) + goto reset; + } + + /* + * A less strict version of mas_is_span_wr() where we allow spanning + * writes within this node. This is to stop partial walks in + * mas_prealloc() from being reset. + */ + if (wr_mas->mas->last > wr_mas->mas->max) + goto reset; + + if (wr_mas->entry) + return; + + if (mte_is_leaf(wr_mas->mas->node) && + wr_mas->mas->last == wr_mas->mas->max) + goto reset; + + return; + +reset: + mas_reset(wr_mas->mas); +} + +/* Interface */ + +/** + * mas_store() - Store an @entry. + * @mas: The maple state. + * @entry: The entry to store. + * + * The @mas->index and @mas->last is used to set the range for the @entry. + * Note: The @mas should have pre-allocated entries to ensure there is memory to + * store the entry. Please see mas_expected_entries()/mas_destroy() for more details. + * + * Return: the first entry between mas->index and mas->last or %NULL. + */ +void *mas_store(struct ma_state *mas, void *entry) +{ + MA_WR_STATE(wr_mas, mas, entry); + + trace_ma_write(__func__, mas, 0, entry); +#ifdef CONFIG_DEBUG_MAPLE_TREE + if (MAS_WARN_ON(mas, mas->index > mas->last)) + pr_err("Error %lX > %lX %p\n", mas->index, mas->last, entry); + + if (mas->index > mas->last) { + mas_set_err(mas, -EINVAL); + return NULL; + } + +#endif + + /* + * Storing is the same operation as insert with the added caveat that it + * can overwrite entries. Although this seems simple enough, one may + * want to examine what happens if a single store operation was to + * overwrite multiple entries within a self-balancing B-Tree. + */ + mas_wr_store_setup(&wr_mas); + mas_wr_store_entry(&wr_mas); + return wr_mas.content; +} +EXPORT_SYMBOL_GPL(mas_store); + +/** + * mas_store_gfp() - Store a value into the tree. + * @mas: The maple state + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations if necessary. + * + * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not + * be allocated. + */ +int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp) +{ + MA_WR_STATE(wr_mas, mas, entry); + + mas_wr_store_setup(&wr_mas); + trace_ma_write(__func__, mas, 0, entry); +retry: + mas_wr_store_entry(&wr_mas); + if (unlikely(mas_nomem(mas, gfp))) + goto retry; + + if (unlikely(mas_is_err(mas))) + return xa_err(mas->node); + + return 0; +} +EXPORT_SYMBOL_GPL(mas_store_gfp); + +/** + * mas_store_prealloc() - Store a value into the tree using memory + * preallocated in the maple state. + * @mas: The maple state + * @entry: The entry to store. + */ +void mas_store_prealloc(struct ma_state *mas, void *entry) +{ + MA_WR_STATE(wr_mas, mas, entry); + + mas_wr_store_setup(&wr_mas); + trace_ma_write(__func__, mas, 0, entry); + mas_wr_store_entry(&wr_mas); + MAS_WR_BUG_ON(&wr_mas, mas_is_err(mas)); + mas_destroy(mas); +} +EXPORT_SYMBOL_GPL(mas_store_prealloc); + +/** + * mas_preallocate() - Preallocate enough nodes for a store operation + * @mas: The maple state + * @entry: The entry that will be stored + * @gfp: The GFP_FLAGS to use for allocations. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated. + */ +int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) +{ + MA_WR_STATE(wr_mas, mas, entry); + unsigned char node_size; + int request = 1; + int ret; + + + if (unlikely(!mas->index && mas->last == ULONG_MAX)) + goto ask_now; + + mas_wr_store_setup(&wr_mas); + wr_mas.content = mas_start(mas); + /* Root expand */ + if (unlikely(mas_is_none(mas) || mas_is_ptr(mas))) + goto ask_now; + + if (unlikely(!mas_wr_walk(&wr_mas))) { + /* Spanning store, use worst case for now */ + request = 1 + mas_mt_height(mas) * 3; + goto ask_now; + } + + /* At this point, we are at the leaf node that needs to be altered. */ + /* Exact fit, no nodes needed. */ + if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last) + return 0; + + mas_wr_end_piv(&wr_mas); + node_size = mas_wr_new_end(&wr_mas); + + /* Slot store, does not require additional nodes */ + if (node_size == mas->end) { + /* reuse node */ + if (!mt_in_rcu(mas->tree)) + return 0; + /* shifting boundary */ + if (wr_mas.offset_end - mas->offset == 1) + return 0; + } + + if (node_size >= mt_slots[wr_mas.type]) { + /* Split, worst case for now. */ + request = 1 + mas_mt_height(mas) * 2; + goto ask_now; + } + + /* New root needs a single node */ + if (unlikely(mte_is_root(mas->node))) + goto ask_now; + + /* Potential spanning rebalance collapsing a node, use worst-case */ + if (node_size - 1 <= mt_min_slots[wr_mas.type]) + request = mas_mt_height(mas) * 2 - 1; + + /* node store, slot store needs one node */ +ask_now: + mas_node_count_gfp(mas, request, gfp); + mas->mas_flags |= MA_STATE_PREALLOC; + if (likely(!mas_is_err(mas))) + return 0; + + mas_set_alloc_req(mas, 0); + ret = xa_err(mas->node); + mas_reset(mas); + mas_destroy(mas); + mas_reset(mas); + return ret; +} +EXPORT_SYMBOL_GPL(mas_preallocate); + +/* + * mas_destroy() - destroy a maple state. + * @mas: The maple state + * + * Upon completion, check the left-most node and rebalance against the node to + * the right if necessary. Frees any allocated nodes associated with this maple + * state. + */ +void mas_destroy(struct ma_state *mas) +{ + struct maple_alloc *node; + unsigned long total; + + /* + * When using mas_for_each() to insert an expected number of elements, + * it is possible that the number inserted is less than the expected + * number. To fix an invalid final node, a check is performed here to + * rebalance the previous node with the final node. + */ + if (mas->mas_flags & MA_STATE_REBALANCE) { + unsigned char end; + + mas_start(mas); + mtree_range_walk(mas); + end = mas->end + 1; + if (end < mt_min_slot_count(mas->node) - 1) + mas_destroy_rebalance(mas, end); + + mas->mas_flags &= ~MA_STATE_REBALANCE; + } + mas->mas_flags &= ~(MA_STATE_BULK|MA_STATE_PREALLOC); + + total = mas_allocated(mas); + while (total) { + node = mas->alloc; + mas->alloc = node->slot[0]; + if (node->node_count > 1) { + size_t count = node->node_count - 1; + + mt_free_bulk(count, (void __rcu **)&node->slot[1]); + total -= count; + } + mt_free_one(ma_mnode_ptr(node)); + total--; + } + + mas->alloc = NULL; +} +EXPORT_SYMBOL_GPL(mas_destroy); + +/* + * mas_expected_entries() - Set the expected number of entries that will be inserted. + * @mas: The maple state + * @nr_entries: The number of expected entries. + * + * This will attempt to pre-allocate enough nodes to store the expected number + * of entries. The allocations will occur using the bulk allocator interface + * for speed. Please call mas_destroy() on the @mas after inserting the entries + * to ensure any unused nodes are freed. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated. + */ +int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries) +{ + int nonleaf_cap = MAPLE_ARANGE64_SLOTS - 2; + struct maple_enode *enode = mas->node; + int nr_nodes; + int ret; + + /* + * Sometimes it is necessary to duplicate a tree to a new tree, such as + * forking a process and duplicating the VMAs from one tree to a new + * tree. When such a situation arises, it is known that the new tree is + * not going to be used until the entire tree is populated. For + * performance reasons, it is best to use a bulk load with RCU disabled. + * This allows for optimistic splitting that favours the left and reuse + * of nodes during the operation. + */ + + /* Optimize splitting for bulk insert in-order */ + mas->mas_flags |= MA_STATE_BULK; + + /* + * Avoid overflow, assume a gap between each entry and a trailing null. + * If this is wrong, it just means allocation can happen during + * insertion of entries. + */ + nr_nodes = max(nr_entries, nr_entries * 2 + 1); + if (!mt_is_alloc(mas->tree)) + nonleaf_cap = MAPLE_RANGE64_SLOTS - 2; + + /* Leaves; reduce slots to keep space for expansion */ + nr_nodes = DIV_ROUND_UP(nr_nodes, MAPLE_RANGE64_SLOTS - 2); + /* Internal nodes */ + nr_nodes += DIV_ROUND_UP(nr_nodes, nonleaf_cap); + /* Add working room for split (2 nodes) + new parents */ + mas_node_count_gfp(mas, nr_nodes + 3, GFP_KERNEL); + + /* Detect if allocations run out */ + mas->mas_flags |= MA_STATE_PREALLOC; + + if (!mas_is_err(mas)) + return 0; + + ret = xa_err(mas->node); + mas->node = enode; + mas_destroy(mas); + return ret; + +} +EXPORT_SYMBOL_GPL(mas_expected_entries); + +static bool mas_next_setup(struct ma_state *mas, unsigned long max, + void **entry) +{ + bool was_none = mas_is_none(mas); + + if (unlikely(mas->last >= max)) { + mas->status = ma_overflow; + return true; + } + + switch (mas->status) { + case ma_active: + return false; + case ma_none: + fallthrough; + case ma_pause: + mas->status = ma_start; + fallthrough; + case ma_start: + mas_walk(mas); /* Retries on dead nodes handled by mas_walk */ + break; + case ma_overflow: + /* Overflowed before, but the max changed */ + mas->status = ma_active; + break; + case ma_underflow: + /* The user expects the mas to be one before where it is */ + mas->status = ma_active; + *entry = mas_walk(mas); + if (*entry) + return true; + break; + case ma_root: + break; + case ma_error: + return true; + } + + if (likely(mas_is_active(mas))) /* Fast path */ + return false; + + if (mas_is_ptr(mas)) { + *entry = NULL; + if (was_none && mas->index == 0) { + mas->index = mas->last = 0; + return true; + } + mas->index = 1; + mas->last = ULONG_MAX; + mas->status = ma_none; + return true; + } + + if (mas_is_none(mas)) + return true; + + return false; +} + +/** + * mas_next() - Get the next entry. + * @mas: The maple state + * @max: The maximum index to check. + * + * Returns the next entry after @mas->index. + * Must hold rcu_read_lock or the write lock. + * Can return the zero entry. + * + * Return: The next entry or %NULL + */ +void *mas_next(struct ma_state *mas, unsigned long max) +{ + void *entry = NULL; + + if (mas_next_setup(mas, max, &entry)) + return entry; + + /* Retries on dead nodes handled by mas_next_slot */ + return mas_next_slot(mas, max, false); +} +EXPORT_SYMBOL_GPL(mas_next); + +/** + * mas_next_range() - Advance the maple state to the next range + * @mas: The maple state + * @max: The maximum index to check. + * + * Sets @mas->index and @mas->last to the range. + * Must hold rcu_read_lock or the write lock. + * Can return the zero entry. + * + * Return: The next entry or %NULL + */ +void *mas_next_range(struct ma_state *mas, unsigned long max) +{ + void *entry = NULL; + + if (mas_next_setup(mas, max, &entry)) + return entry; + + /* Retries on dead nodes handled by mas_next_slot */ + return mas_next_slot(mas, max, true); +} +EXPORT_SYMBOL_GPL(mas_next_range); + +/** + * mt_next() - get the next value in the maple tree + * @mt: The maple tree + * @index: The start index + * @max: The maximum index to check + * + * Takes RCU read lock internally to protect the search, which does not + * protect the returned pointer after dropping RCU read lock. + * See also: Documentation/core-api/maple_tree.rst + * + * Return: The entry higher than @index or %NULL if nothing is found. + */ +void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max) +{ + void *entry = NULL; + MA_STATE(mas, mt, index, index); + + rcu_read_lock(); + entry = mas_next(&mas, max); + rcu_read_unlock(); + return entry; +} +EXPORT_SYMBOL_GPL(mt_next); + +static bool mas_prev_setup(struct ma_state *mas, unsigned long min, void **entry) +{ + if (unlikely(mas->index <= min)) { + mas->status = ma_underflow; + return true; + } + + switch (mas->status) { + case ma_active: + return false; + case ma_start: + break; + case ma_none: + fallthrough; + case ma_pause: + mas->status = ma_start; + break; + case ma_underflow: + /* underflowed before but the min changed */ + mas->status = ma_active; + break; + case ma_overflow: + /* User expects mas to be one after where it is */ + mas->status = ma_active; + *entry = mas_walk(mas); + if (*entry) + return true; + break; + case ma_root: + break; + case ma_error: + return true; + } + + if (mas_is_start(mas)) + mas_walk(mas); + + if (unlikely(mas_is_ptr(mas))) { + if (!mas->index) { + mas->status = ma_none; + return true; + } + mas->index = mas->last = 0; + *entry = mas_root(mas); + return true; + } + + if (mas_is_none(mas)) { + if (mas->index) { + /* Walked to out-of-range pointer? */ + mas->index = mas->last = 0; + mas->status = ma_root; + *entry = mas_root(mas); + return true; + } + return true; + } + + return false; +} + +/** + * mas_prev() - Get the previous entry + * @mas: The maple state + * @min: The minimum value to check. + * + * Must hold rcu_read_lock or the write lock. + * Will reset mas to ma_start if the status is ma_none. Will stop on not + * searchable nodes. + * + * Return: the previous value or %NULL. + */ +void *mas_prev(struct ma_state *mas, unsigned long min) +{ + void *entry = NULL; + + if (mas_prev_setup(mas, min, &entry)) + return entry; + + return mas_prev_slot(mas, min, false); +} +EXPORT_SYMBOL_GPL(mas_prev); + +/** + * mas_prev_range() - Advance to the previous range + * @mas: The maple state + * @min: The minimum value to check. + * + * Sets @mas->index and @mas->last to the range. + * Must hold rcu_read_lock or the write lock. + * Will reset mas to ma_start if the node is ma_none. Will stop on not + * searchable nodes. + * + * Return: the previous value or %NULL. + */ +void *mas_prev_range(struct ma_state *mas, unsigned long min) +{ + void *entry = NULL; + + if (mas_prev_setup(mas, min, &entry)) + return entry; + + return mas_prev_slot(mas, min, true); +} +EXPORT_SYMBOL_GPL(mas_prev_range); + +/** + * mt_prev() - get the previous value in the maple tree + * @mt: The maple tree + * @index: The start index + * @min: The minimum index to check + * + * Takes RCU read lock internally to protect the search, which does not + * protect the returned pointer after dropping RCU read lock. + * See also: Documentation/core-api/maple_tree.rst + * + * Return: The entry before @index or %NULL if nothing is found. + */ +void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min) +{ + void *entry = NULL; + MA_STATE(mas, mt, index, index); + + rcu_read_lock(); + entry = mas_prev(&mas, min); + rcu_read_unlock(); + return entry; +} +EXPORT_SYMBOL_GPL(mt_prev); + +/** + * mas_pause() - Pause a mas_find/mas_for_each to drop the lock. + * @mas: The maple state to pause + * + * Some users need to pause a walk and drop the lock they're holding in + * order to yield to a higher priority thread or carry out an operation + * on an entry. Those users should call this function before they drop + * the lock. It resets the @mas to be suitable for the next iteration + * of the loop after the user has reacquired the lock. If most entries + * found during a walk require you to call mas_pause(), the mt_for_each() + * iterator may be more appropriate. + * + */ +void mas_pause(struct ma_state *mas) +{ + mas->status = ma_pause; + mas->node = NULL; +} +EXPORT_SYMBOL_GPL(mas_pause); + +/** + * mas_find_setup() - Internal function to set up mas_find*(). + * @mas: The maple state + * @max: The maximum index + * @entry: Pointer to the entry + * + * Returns: True if entry is the answer, false otherwise. + */ +static __always_inline bool mas_find_setup(struct ma_state *mas, unsigned long max, void **entry) +{ + switch (mas->status) { + case ma_active: + if (mas->last < max) + return false; + return true; + case ma_start: + break; + case ma_pause: + if (unlikely(mas->last >= max)) + return true; + + mas->index = ++mas->last; + mas->status = ma_start; + break; + case ma_none: + if (unlikely(mas->last >= max)) + return true; + + mas->index = mas->last; + mas->status = ma_start; + break; + case ma_underflow: + /* mas is pointing at entry before unable to go lower */ + if (unlikely(mas->index >= max)) { + mas->status = ma_overflow; + return true; + } + + mas->status = ma_active; + *entry = mas_walk(mas); + if (*entry) + return true; + break; + case ma_overflow: + if (unlikely(mas->last >= max)) + return true; + + mas->status = ma_active; + *entry = mas_walk(mas); + if (*entry) + return true; + break; + case ma_root: + break; + case ma_error: + return true; + } + + if (mas_is_start(mas)) { + /* First run or continue */ + if (mas->index > max) + return true; + + *entry = mas_walk(mas); + if (*entry) + return true; + + } + + if (unlikely(mas_is_ptr(mas))) + goto ptr_out_of_range; + + if (unlikely(mas_is_none(mas))) + return true; + + if (mas->index == max) + return true; + + return false; + +ptr_out_of_range: + mas->status = ma_none; + mas->index = 1; + mas->last = ULONG_MAX; + return true; +} + +/** + * mas_find() - On the first call, find the entry at or after mas->index up to + * %max. Otherwise, find the entry after mas->index. + * @mas: The maple state + * @max: The maximum value to check. + * + * Must hold rcu_read_lock or the write lock. + * If an entry exists, last and index are updated accordingly. + * May set @mas->status to ma_overflow. + * + * Return: The entry or %NULL. + */ +void *mas_find(struct ma_state *mas, unsigned long max) +{ + void *entry = NULL; + + if (mas_find_setup(mas, max, &entry)) + return entry; + + /* Retries on dead nodes handled by mas_next_slot */ + entry = mas_next_slot(mas, max, false); + /* Ignore overflow */ + mas->status = ma_active; + return entry; +} +EXPORT_SYMBOL_GPL(mas_find); + +/** + * mas_find_range() - On the first call, find the entry at or after + * mas->index up to %max. Otherwise, advance to the next slot mas->index. + * @mas: The maple state + * @max: The maximum value to check. + * + * Must hold rcu_read_lock or the write lock. + * If an entry exists, last and index are updated accordingly. + * May set @mas->status to ma_overflow. + * + * Return: The entry or %NULL. + */ +void *mas_find_range(struct ma_state *mas, unsigned long max) +{ + void *entry = NULL; + + if (mas_find_setup(mas, max, &entry)) + return entry; + + /* Retries on dead nodes handled by mas_next_slot */ + return mas_next_slot(mas, max, true); +} +EXPORT_SYMBOL_GPL(mas_find_range); + +/** + * mas_find_rev_setup() - Internal function to set up mas_find_*_rev() + * @mas: The maple state + * @min: The minimum index + * @entry: Pointer to the entry + * + * Returns: True if entry is the answer, false otherwise. + */ +static bool mas_find_rev_setup(struct ma_state *mas, unsigned long min, + void **entry) +{ + + switch (mas->status) { + case ma_active: + goto active; + case ma_start: + break; + case ma_pause: + if (unlikely(mas->index <= min)) { + mas->status = ma_underflow; + return true; + } + mas->last = --mas->index; + mas->status = ma_start; + break; + case ma_none: + if (mas->index <= min) + goto none; + + mas->last = mas->index; + mas->status = ma_start; + break; + case ma_overflow: /* user expects the mas to be one after where it is */ + if (unlikely(mas->index <= min)) { + mas->status = ma_underflow; + return true; + } + + mas->status = ma_active; + break; + case ma_underflow: /* user expects the mas to be one before where it is */ + if (unlikely(mas->index <= min)) + return true; + + mas->status = ma_active; + break; + case ma_root: + break; + case ma_error: + return true; + } + + if (mas_is_start(mas)) { + /* First run or continue */ + if (mas->index < min) + return true; + + *entry = mas_walk(mas); + if (*entry) + return true; + } + + if (unlikely(mas_is_ptr(mas))) + goto none; + + if (unlikely(mas_is_none(mas))) { + /* + * Walked to the location, and there was nothing so the previous + * location is 0. + */ + mas->last = mas->index = 0; + mas->status = ma_root; + *entry = mas_root(mas); + return true; + } + +active: + if (mas->index < min) + return true; + + return false; + +none: + mas->status = ma_none; + return true; +} + +/** + * mas_find_rev: On the first call, find the first non-null entry at or below + * mas->index down to %min. Otherwise find the first non-null entry below + * mas->index down to %min. + * @mas: The maple state + * @min: The minimum value to check. + * + * Must hold rcu_read_lock or the write lock. + * If an entry exists, last and index are updated accordingly. + * May set @mas->status to ma_underflow. + * + * Return: The entry or %NULL. + */ +void *mas_find_rev(struct ma_state *mas, unsigned long min) +{ + void *entry = NULL; + + if (mas_find_rev_setup(mas, min, &entry)) + return entry; + + /* Retries on dead nodes handled by mas_prev_slot */ + return mas_prev_slot(mas, min, false); + +} +EXPORT_SYMBOL_GPL(mas_find_rev); + +/** + * mas_find_range_rev: On the first call, find the first non-null entry at or + * below mas->index down to %min. Otherwise advance to the previous slot after + * mas->index down to %min. + * @mas: The maple state + * @min: The minimum value to check. + * + * Must hold rcu_read_lock or the write lock. + * If an entry exists, last and index are updated accordingly. + * May set @mas->status to ma_underflow. + * + * Return: The entry or %NULL. + */ +void *mas_find_range_rev(struct ma_state *mas, unsigned long min) +{ + void *entry = NULL; + + if (mas_find_rev_setup(mas, min, &entry)) + return entry; + + /* Retries on dead nodes handled by mas_prev_slot */ + return mas_prev_slot(mas, min, true); +} +EXPORT_SYMBOL_GPL(mas_find_range_rev); + +/** + * mas_erase() - Find the range in which index resides and erase the entire + * range. + * @mas: The maple state + * + * Must hold the write lock. + * Searches for @mas->index, sets @mas->index and @mas->last to the range and + * erases that range. + * + * Return: the entry that was erased or %NULL, @mas->index and @mas->last are updated. + */ +void *mas_erase(struct ma_state *mas) +{ + void *entry; + MA_WR_STATE(wr_mas, mas, NULL); + + if (!mas_is_active(mas) || !mas_is_start(mas)) + mas->status = ma_start; + + /* Retry unnecessary when holding the write lock. */ + entry = mas_state_walk(mas); + if (!entry) + return NULL; + +write_retry: + /* Must reset to ensure spanning writes of last slot are detected */ + mas_reset(mas); + mas_wr_store_setup(&wr_mas); + mas_wr_store_entry(&wr_mas); + if (mas_nomem(mas, GFP_KERNEL)) + goto write_retry; + + return entry; +} +EXPORT_SYMBOL_GPL(mas_erase); + +/** + * mas_nomem() - Check if there was an error allocating and do the allocation + * if necessary If there are allocations, then free them. + * @mas: The maple state + * @gfp: The GFP_FLAGS to use for allocations + * Return: true on allocation, false otherwise. + */ +bool mas_nomem(struct ma_state *mas, gfp_t gfp) + __must_hold(mas->tree->ma_lock) +{ + if (likely(mas->node != MA_ERROR(-ENOMEM))) { + mas_destroy(mas); + return false; + } + + if (gfpflags_allow_blocking(gfp) && !mt_external_lock(mas->tree)) { + mtree_unlock(mas->tree); + mas_alloc_nodes(mas, gfp); + mtree_lock(mas->tree); + } else { + mas_alloc_nodes(mas, gfp); + } + + if (!mas_allocated(mas)) + return false; + + mas->status = ma_start; + return true; +} + +void __init maple_tree_init(void) +{ + maple_node_cache = kmem_cache_create("maple_node", + sizeof(struct maple_node), sizeof(struct maple_node), + SLAB_PANIC, NULL); +} + +/** + * mtree_load() - Load a value stored in a maple tree + * @mt: The maple tree + * @index: The index to load + * + * Return: the entry or %NULL + */ +void *mtree_load(struct maple_tree *mt, unsigned long index) +{ + MA_STATE(mas, mt, index, index); + void *entry; + + trace_ma_read(__func__, &mas); + rcu_read_lock(); +retry: + entry = mas_start(&mas); + if (unlikely(mas_is_none(&mas))) + goto unlock; + + if (unlikely(mas_is_ptr(&mas))) { + if (index) + entry = NULL; + + goto unlock; + } + + entry = mtree_lookup_walk(&mas); + if (!entry && unlikely(mas_is_start(&mas))) + goto retry; +unlock: + rcu_read_unlock(); + if (xa_is_zero(entry)) + return NULL; + + return entry; +} +EXPORT_SYMBOL(mtree_load); + +/** + * mtree_store_range() - Store an entry at a given range. + * @mt: The maple tree + * @index: The start of the range + * @last: The end of the range + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations + * + * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not + * be allocated. + */ +int mtree_store_range(struct maple_tree *mt, unsigned long index, + unsigned long last, void *entry, gfp_t gfp) +{ + MA_STATE(mas, mt, index, last); + MA_WR_STATE(wr_mas, &mas, entry); + + trace_ma_write(__func__, &mas, 0, entry); + if (WARN_ON_ONCE(xa_is_advanced(entry))) + return -EINVAL; + + if (index > last) + return -EINVAL; + + mtree_lock(mt); +retry: + mas_wr_store_entry(&wr_mas); + if (mas_nomem(&mas, gfp)) + goto retry; + + mtree_unlock(mt); + if (mas_is_err(&mas)) + return xa_err(mas.node); + + return 0; +} +EXPORT_SYMBOL(mtree_store_range); + +/** + * mtree_store() - Store an entry at a given index. + * @mt: The maple tree + * @index: The index to store the value + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations + * + * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not + * be allocated. + */ +int mtree_store(struct maple_tree *mt, unsigned long index, void *entry, + gfp_t gfp) +{ + return mtree_store_range(mt, index, index, entry, gfp); +} +EXPORT_SYMBOL(mtree_store); + +/** + * mtree_insert_range() - Insert an entry at a given range if there is no value. + * @mt: The maple tree + * @first: The start of the range + * @last: The end of the range + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations. + * + * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid + * request, -ENOMEM if memory could not be allocated. + */ +int mtree_insert_range(struct maple_tree *mt, unsigned long first, + unsigned long last, void *entry, gfp_t gfp) +{ + MA_STATE(ms, mt, first, last); + + if (WARN_ON_ONCE(xa_is_advanced(entry))) + return -EINVAL; + + if (first > last) + return -EINVAL; + + mtree_lock(mt); +retry: + mas_insert(&ms, entry); + if (mas_nomem(&ms, gfp)) + goto retry; + + mtree_unlock(mt); + if (mas_is_err(&ms)) + return xa_err(ms.node); + + return 0; +} +EXPORT_SYMBOL(mtree_insert_range); + +/** + * mtree_insert() - Insert an entry at a given index if there is no value. + * @mt: The maple tree + * @index : The index to store the value + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations. + * + * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid + * request, -ENOMEM if memory could not be allocated. + */ +int mtree_insert(struct maple_tree *mt, unsigned long index, void *entry, + gfp_t gfp) +{ + return mtree_insert_range(mt, index, index, entry, gfp); +} +EXPORT_SYMBOL(mtree_insert); + +int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long size, unsigned long min, + unsigned long max, gfp_t gfp) +{ + int ret = 0; + + MA_STATE(mas, mt, 0, 0); + if (!mt_is_alloc(mt)) + return -EINVAL; + + if (WARN_ON_ONCE(mt_is_reserved(entry))) + return -EINVAL; + + mtree_lock(mt); +retry: + ret = mas_empty_area(&mas, min, max, size); + if (ret) + goto unlock; + + mas_insert(&mas, entry); + /* + * mas_nomem() may release the lock, causing the allocated area + * to be unavailable, so try to allocate a free area again. + */ + if (mas_nomem(&mas, gfp)) + goto retry; + + if (mas_is_err(&mas)) + ret = xa_err(mas.node); + else + *startp = mas.index; + +unlock: + mtree_unlock(mt); + return ret; +} +EXPORT_SYMBOL(mtree_alloc_range); + +int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long size, unsigned long min, + unsigned long max, gfp_t gfp) +{ + int ret = 0; + + MA_STATE(mas, mt, 0, 0); + if (!mt_is_alloc(mt)) + return -EINVAL; + + if (WARN_ON_ONCE(mt_is_reserved(entry))) + return -EINVAL; + + mtree_lock(mt); +retry: + ret = mas_empty_area_rev(&mas, min, max, size); + if (ret) + goto unlock; + + mas_insert(&mas, entry); + /* + * mas_nomem() may release the lock, causing the allocated area + * to be unavailable, so try to allocate a free area again. + */ + if (mas_nomem(&mas, gfp)) + goto retry; + + if (mas_is_err(&mas)) + ret = xa_err(mas.node); + else + *startp = mas.index; + +unlock: + mtree_unlock(mt); + return ret; +} +EXPORT_SYMBOL(mtree_alloc_rrange); + +/** + * mtree_erase() - Find an index and erase the entire range. + * @mt: The maple tree + * @index: The index to erase + * + * Erasing is the same as a walk to an entry then a store of a NULL to that + * ENTIRE range. In fact, it is implemented as such using the advanced API. + * + * Return: The entry stored at the @index or %NULL + */ +void *mtree_erase(struct maple_tree *mt, unsigned long index) +{ + void *entry = NULL; + + MA_STATE(mas, mt, index, index); + trace_ma_op(__func__, &mas); + + mtree_lock(mt); + entry = mas_erase(&mas); + mtree_unlock(mt); + + return entry; +} +EXPORT_SYMBOL(mtree_erase); + +/* + * mas_dup_free() - Free an incomplete duplication of a tree. + * @mas: The maple state of a incomplete tree. + * + * The parameter @mas->node passed in indicates that the allocation failed on + * this node. This function frees all nodes starting from @mas->node in the + * reverse order of mas_dup_build(). There is no need to hold the source tree + * lock at this time. + */ +static void mas_dup_free(struct ma_state *mas) +{ + struct maple_node *node; + enum maple_type type; + void __rcu **slots; + unsigned char count, i; + + /* Maybe the first node allocation failed. */ + if (mas_is_none(mas)) + return; + + while (!mte_is_root(mas->node)) { + mas_ascend(mas); + if (mas->offset) { + mas->offset--; + do { + mas_descend(mas); + mas->offset = mas_data_end(mas); + } while (!mte_is_leaf(mas->node)); + + mas_ascend(mas); + } + + node = mte_to_node(mas->node); + type = mte_node_type(mas->node); + slots = ma_slots(node, type); + count = mas_data_end(mas) + 1; + for (i = 0; i < count; i++) + ((unsigned long *)slots)[i] &= ~MAPLE_NODE_MASK; + mt_free_bulk(count, slots); + } + + node = mte_to_node(mas->node); + mt_free_one(node); +} + +/* + * mas_copy_node() - Copy a maple node and replace the parent. + * @mas: The maple state of source tree. + * @new_mas: The maple state of new tree. + * @parent: The parent of the new node. + * + * Copy @mas->node to @new_mas->node, set @parent to be the parent of + * @new_mas->node. If memory allocation fails, @mas is set to -ENOMEM. + */ +static inline void mas_copy_node(struct ma_state *mas, struct ma_state *new_mas, + struct maple_pnode *parent) +{ + struct maple_node *node = mte_to_node(mas->node); + struct maple_node *new_node = mte_to_node(new_mas->node); + unsigned long val; + + /* Copy the node completely. */ + memcpy(new_node, node, sizeof(struct maple_node)); + /* Update the parent node pointer. */ + val = (unsigned long)node->parent & MAPLE_NODE_MASK; + new_node->parent = ma_parent_ptr(val | (unsigned long)parent); +} + +/* + * mas_dup_alloc() - Allocate child nodes for a maple node. + * @mas: The maple state of source tree. + * @new_mas: The maple state of new tree. + * @gfp: The GFP_FLAGS to use for allocations. + * + * This function allocates child nodes for @new_mas->node during the duplication + * process. If memory allocation fails, @mas is set to -ENOMEM. + */ +static inline void mas_dup_alloc(struct ma_state *mas, struct ma_state *new_mas, + gfp_t gfp) +{ + struct maple_node *node = mte_to_node(mas->node); + struct maple_node *new_node = mte_to_node(new_mas->node); + enum maple_type type; + unsigned char request, count, i; + void __rcu **slots; + void __rcu **new_slots; + unsigned long val; + + /* Allocate memory for child nodes. */ + type = mte_node_type(mas->node); + new_slots = ma_slots(new_node, type); + request = mas_data_end(mas) + 1; + count = mt_alloc_bulk(gfp, request, (void **)new_slots); + if (unlikely(count < request)) { + memset(new_slots, 0, request * sizeof(void *)); + mas_set_err(mas, -ENOMEM); + return; + } + + /* Restore node type information in slots. */ + slots = ma_slots(node, type); + for (i = 0; i < count; i++) { + val = (unsigned long)mt_slot_locked(mas->tree, slots, i); + val &= MAPLE_NODE_MASK; + ((unsigned long *)new_slots)[i] |= val; + } +} + +/* + * mas_dup_build() - Build a new maple tree from a source tree + * @mas: The maple state of source tree, need to be in MAS_START state. + * @new_mas: The maple state of new tree, need to be in MAS_START state. + * @gfp: The GFP_FLAGS to use for allocations. + * + * This function builds a new tree in DFS preorder. If the memory allocation + * fails, the error code -ENOMEM will be set in @mas, and @new_mas points to the + * last node. mas_dup_free() will free the incomplete duplication of a tree. + * + * Note that the attributes of the two trees need to be exactly the same, and the + * new tree needs to be empty, otherwise -EINVAL will be set in @mas. + */ +static inline void mas_dup_build(struct ma_state *mas, struct ma_state *new_mas, + gfp_t gfp) +{ + struct maple_node *node; + struct maple_pnode *parent = NULL; + struct maple_enode *root; + enum maple_type type; + + if (unlikely(mt_attr(mas->tree) != mt_attr(new_mas->tree)) || + unlikely(!mtree_empty(new_mas->tree))) { + mas_set_err(mas, -EINVAL); + return; + } + + root = mas_start(mas); + if (mas_is_ptr(mas) || mas_is_none(mas)) + goto set_new_tree; + + node = mt_alloc_one(gfp); + if (!node) { + new_mas->status = ma_none; + mas_set_err(mas, -ENOMEM); + return; + } + + type = mte_node_type(mas->node); + root = mt_mk_node(node, type); + new_mas->node = root; + new_mas->min = 0; + new_mas->max = ULONG_MAX; + root = mte_mk_root(root); + while (1) { + mas_copy_node(mas, new_mas, parent); + if (!mte_is_leaf(mas->node)) { + /* Only allocate child nodes for non-leaf nodes. */ + mas_dup_alloc(mas, new_mas, gfp); + if (unlikely(mas_is_err(mas))) + return; + } else { + /* + * This is the last leaf node and duplication is + * completed. + */ + if (mas->max == ULONG_MAX) + goto done; + + /* This is not the last leaf node and needs to go up. */ + do { + mas_ascend(mas); + mas_ascend(new_mas); + } while (mas->offset == mas_data_end(mas)); + + /* Move to the next subtree. */ + mas->offset++; + new_mas->offset++; + } + + mas_descend(mas); + parent = ma_parent_ptr(mte_to_node(new_mas->node)); + mas_descend(new_mas); + mas->offset = 0; + new_mas->offset = 0; + } +done: + /* Specially handle the parent of the root node. */ + mte_to_node(root)->parent = ma_parent_ptr(mas_tree_parent(new_mas)); +set_new_tree: + /* Make them the same height */ + new_mas->tree->ma_flags = mas->tree->ma_flags; + rcu_assign_pointer(new_mas->tree->ma_root, root); +} + +/** + * __mt_dup(): Duplicate an entire maple tree + * @mt: The source maple tree + * @new: The new maple tree + * @gfp: The GFP_FLAGS to use for allocations + * + * This function duplicates a maple tree in Depth-First Search (DFS) pre-order + * traversal. It uses memcpy() to copy nodes in the source tree and allocate + * new child nodes in non-leaf nodes. The new node is exactly the same as the + * source node except for all the addresses stored in it. It will be faster than + * traversing all elements in the source tree and inserting them one by one into + * the new tree. + * The user needs to ensure that the attributes of the source tree and the new + * tree are the same, and the new tree needs to be an empty tree, otherwise + * -EINVAL will be returned. + * Note that the user needs to manually lock the source tree and the new tree. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated, -EINVAL If + * the attributes of the two trees are different or the new tree is not an empty + * tree. + */ +int __mt_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp) +{ + int ret = 0; + MA_STATE(mas, mt, 0, 0); + MA_STATE(new_mas, new, 0, 0); + + mas_dup_build(&mas, &new_mas, gfp); + if (unlikely(mas_is_err(&mas))) { + ret = xa_err(mas.node); + if (ret == -ENOMEM) + mas_dup_free(&new_mas); + } + + return ret; +} +EXPORT_SYMBOL(__mt_dup); + +/** + * mtree_dup(): Duplicate an entire maple tree + * @mt: The source maple tree + * @new: The new maple tree + * @gfp: The GFP_FLAGS to use for allocations + * + * This function duplicates a maple tree in Depth-First Search (DFS) pre-order + * traversal. It uses memcpy() to copy nodes in the source tree and allocate + * new child nodes in non-leaf nodes. The new node is exactly the same as the + * source node except for all the addresses stored in it. It will be faster than + * traversing all elements in the source tree and inserting them one by one into + * the new tree. + * The user needs to ensure that the attributes of the source tree and the new + * tree are the same, and the new tree needs to be an empty tree, otherwise + * -EINVAL will be returned. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated, -EINVAL If + * the attributes of the two trees are different or the new tree is not an empty + * tree. + */ +int mtree_dup(struct maple_tree *mt, struct maple_tree *new, gfp_t gfp) +{ + int ret = 0; + MA_STATE(mas, mt, 0, 0); + MA_STATE(new_mas, new, 0, 0); + + mas_lock(&new_mas); + mas_lock_nested(&mas, SINGLE_DEPTH_NESTING); + mas_dup_build(&mas, &new_mas, gfp); + mas_unlock(&mas); + if (unlikely(mas_is_err(&mas))) { + ret = xa_err(mas.node); + if (ret == -ENOMEM) + mas_dup_free(&new_mas); + } + + mas_unlock(&new_mas); + return ret; +} +EXPORT_SYMBOL(mtree_dup); + +/** + * __mt_destroy() - Walk and free all nodes of a locked maple tree. + * @mt: The maple tree + * + * Note: Does not handle locking. + */ +void __mt_destroy(struct maple_tree *mt) +{ + void *root = mt_root_locked(mt); + + rcu_assign_pointer(mt->ma_root, NULL); + if (xa_is_node(root)) + mte_destroy_walk(root, mt); + + mt->ma_flags = mt_attr(mt); +} +EXPORT_SYMBOL_GPL(__mt_destroy); + +/** + * mtree_destroy() - Destroy a maple tree + * @mt: The maple tree + * + * Frees all resources used by the tree. Handles locking. + */ +void mtree_destroy(struct maple_tree *mt) +{ + mtree_lock(mt); + __mt_destroy(mt); + mtree_unlock(mt); +} +EXPORT_SYMBOL(mtree_destroy); + +/** + * mt_find() - Search from the start up until an entry is found. + * @mt: The maple tree + * @index: Pointer which contains the start location of the search + * @max: The maximum value of the search range + * + * Takes RCU read lock internally to protect the search, which does not + * protect the returned pointer after dropping RCU read lock. + * See also: Documentation/core-api/maple_tree.rst + * + * In case that an entry is found @index is updated to point to the next + * possible entry independent whether the found entry is occupying a + * single index or a range if indices. + * + * Return: The entry at or after the @index or %NULL + */ +void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max) +{ + MA_STATE(mas, mt, *index, *index); + void *entry; +#ifdef CONFIG_DEBUG_MAPLE_TREE + unsigned long copy = *index; +#endif + + trace_ma_read(__func__, &mas); + + if ((*index) > max) + return NULL; + + rcu_read_lock(); +retry: + entry = mas_state_walk(&mas); + if (mas_is_start(&mas)) + goto retry; + + if (unlikely(xa_is_zero(entry))) + entry = NULL; + + if (entry) + goto unlock; + + while (mas_is_active(&mas) && (mas.last < max)) { + entry = mas_next_entry(&mas, max); + if (likely(entry && !xa_is_zero(entry))) + break; + } + + if (unlikely(xa_is_zero(entry))) + entry = NULL; +unlock: + rcu_read_unlock(); + if (likely(entry)) { + *index = mas.last + 1; +#ifdef CONFIG_DEBUG_MAPLE_TREE + if (MT_WARN_ON(mt, (*index) && ((*index) <= copy))) + pr_err("index not increased! %lx <= %lx\n", + *index, copy); +#endif + } + + return entry; +} +EXPORT_SYMBOL(mt_find); + +/** + * mt_find_after() - Search from the start up until an entry is found. + * @mt: The maple tree + * @index: Pointer which contains the start location of the search + * @max: The maximum value to check + * + * Same as mt_find() except that it checks @index for 0 before + * searching. If @index == 0, the search is aborted. This covers a wrap + * around of @index to 0 in an iterator loop. + * + * Return: The entry at or after the @index or %NULL + */ +void *mt_find_after(struct maple_tree *mt, unsigned long *index, + unsigned long max) +{ + if (!(*index)) + return NULL; + + return mt_find(mt, index, max); +} +EXPORT_SYMBOL(mt_find_after); + +#ifdef CONFIG_DEBUG_MAPLE_TREE +atomic_t maple_tree_tests_run; +EXPORT_SYMBOL_GPL(maple_tree_tests_run); +atomic_t maple_tree_tests_passed; +EXPORT_SYMBOL_GPL(maple_tree_tests_passed); + +#ifndef __KERNEL__ +extern void kmem_cache_set_non_kernel(struct kmem_cache *, unsigned int); +void mt_set_non_kernel(unsigned int val) +{ + kmem_cache_set_non_kernel(maple_node_cache, val); +} + +extern unsigned long kmem_cache_get_alloc(struct kmem_cache *); +unsigned long mt_get_alloc_size(void) +{ + return kmem_cache_get_alloc(maple_node_cache); +} + +extern void kmem_cache_zero_nr_tallocated(struct kmem_cache *); +void mt_zero_nr_tallocated(void) +{ + kmem_cache_zero_nr_tallocated(maple_node_cache); +} + +extern unsigned int kmem_cache_nr_tallocated(struct kmem_cache *); +unsigned int mt_nr_tallocated(void) +{ + return kmem_cache_nr_tallocated(maple_node_cache); +} + +extern unsigned int kmem_cache_nr_allocated(struct kmem_cache *); +unsigned int mt_nr_allocated(void) +{ + return kmem_cache_nr_allocated(maple_node_cache); +} + +void mt_cache_shrink(void) +{ +} +#else +/* + * mt_cache_shrink() - For testing, don't use this. + * + * Certain testcases can trigger an OOM when combined with other memory + * debugging configuration options. This function is used to reduce the + * possibility of an out of memory even due to kmem_cache objects remaining + * around for longer than usual. + */ +void mt_cache_shrink(void) +{ + kmem_cache_shrink(maple_node_cache); + +} +EXPORT_SYMBOL_GPL(mt_cache_shrink); + +#endif /* not defined __KERNEL__ */ +/* + * mas_get_slot() - Get the entry in the maple state node stored at @offset. + * @mas: The maple state + * @offset: The offset into the slot array to fetch. + * + * Return: The entry stored at @offset. + */ +static inline struct maple_enode *mas_get_slot(struct ma_state *mas, + unsigned char offset) +{ + return mas_slot(mas, ma_slots(mas_mn(mas), mte_node_type(mas->node)), + offset); +} + +/* Depth first search, post-order */ +static void mas_dfs_postorder(struct ma_state *mas, unsigned long max) +{ + + struct maple_enode *p, *mn = mas->node; + unsigned long p_min, p_max; + + mas_next_node(mas, mas_mn(mas), max); + if (!mas_is_overflow(mas)) + return; + + if (mte_is_root(mn)) + return; + + mas->node = mn; + mas_ascend(mas); + do { + p = mas->node; + p_min = mas->min; + p_max = mas->max; + mas_prev_node(mas, 0); + } while (!mas_is_underflow(mas)); + + mas->node = p; + mas->max = p_max; + mas->min = p_min; +} + +/* Tree validations */ +static void mt_dump_node(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth, + enum mt_dump_format format); +static void mt_dump_range(unsigned long min, unsigned long max, + unsigned int depth, enum mt_dump_format format) +{ + static const char spaces[] = " "; + + switch(format) { + case mt_dump_hex: + if (min == max) + pr_info("%.*s%lx: ", depth * 2, spaces, min); + else + pr_info("%.*s%lx-%lx: ", depth * 2, spaces, min, max); + break; + case mt_dump_dec: + if (min == max) + pr_info("%.*s%lu: ", depth * 2, spaces, min); + else + pr_info("%.*s%lu-%lu: ", depth * 2, spaces, min, max); + } +} + +static void mt_dump_entry(void *entry, unsigned long min, unsigned long max, + unsigned int depth, enum mt_dump_format format) +{ + mt_dump_range(min, max, depth, format); + + if (xa_is_value(entry)) + pr_cont("value %ld (0x%lx) [%p]\n", xa_to_value(entry), + xa_to_value(entry), entry); + else if (xa_is_zero(entry)) + pr_cont("zero (%ld)\n", xa_to_internal(entry)); + else if (mt_is_reserved(entry)) + pr_cont("UNKNOWN ENTRY (%p)\n", entry); + else + pr_cont("%p\n", entry); +} + +static void mt_dump_range64(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth, + enum mt_dump_format format) +{ + struct maple_range_64 *node = &mte_to_node(entry)->mr64; + bool leaf = mte_is_leaf(entry); + unsigned long first = min; + int i; + + pr_cont(" contents: "); + for (i = 0; i < MAPLE_RANGE64_SLOTS - 1; i++) { + switch(format) { + case mt_dump_hex: + pr_cont("%p %lX ", node->slot[i], node->pivot[i]); + break; + case mt_dump_dec: + pr_cont("%p %lu ", node->slot[i], node->pivot[i]); + } + } + pr_cont("%p\n", node->slot[i]); + for (i = 0; i < MAPLE_RANGE64_SLOTS; i++) { + unsigned long last = max; + + if (i < (MAPLE_RANGE64_SLOTS - 1)) + last = node->pivot[i]; + else if (!node->slot[i] && max != mt_node_max(entry)) + break; + if (last == 0 && i > 0) + break; + if (leaf) + mt_dump_entry(mt_slot(mt, node->slot, i), + first, last, depth + 1, format); + else if (node->slot[i]) + mt_dump_node(mt, mt_slot(mt, node->slot, i), + first, last, depth + 1, format); + + if (last == max) + break; + if (last > max) { + switch(format) { + case mt_dump_hex: + pr_err("node %p last (%lx) > max (%lx) at pivot %d!\n", + node, last, max, i); + break; + case mt_dump_dec: + pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n", + node, last, max, i); + } + } + first = last + 1; + } +} + +static void mt_dump_arange64(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth, + enum mt_dump_format format) +{ + struct maple_arange_64 *node = &mte_to_node(entry)->ma64; + bool leaf = mte_is_leaf(entry); + unsigned long first = min; + int i; + + pr_cont(" contents: "); + for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) { + switch (format) { + case mt_dump_hex: + pr_cont("%lx ", node->gap[i]); + break; + case mt_dump_dec: + pr_cont("%lu ", node->gap[i]); + } + } + pr_cont("| %02X %02X| ", node->meta.end, node->meta.gap); + for (i = 0; i < MAPLE_ARANGE64_SLOTS - 1; i++) { + switch (format) { + case mt_dump_hex: + pr_cont("%p %lX ", node->slot[i], node->pivot[i]); + break; + case mt_dump_dec: + pr_cont("%p %lu ", node->slot[i], node->pivot[i]); + } + } + pr_cont("%p\n", node->slot[i]); + for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) { + unsigned long last = max; + + if (i < (MAPLE_ARANGE64_SLOTS - 1)) + last = node->pivot[i]; + else if (!node->slot[i]) + break; + if (last == 0 && i > 0) + break; + if (leaf) + mt_dump_entry(mt_slot(mt, node->slot, i), + first, last, depth + 1, format); + else if (node->slot[i]) + mt_dump_node(mt, mt_slot(mt, node->slot, i), + first, last, depth + 1, format); + + if (last == max) + break; + if (last > max) { + pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n", + node, last, max, i); + break; + } + first = last + 1; + } +} + +static void mt_dump_node(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth, + enum mt_dump_format format) +{ + struct maple_node *node = mte_to_node(entry); + unsigned int type = mte_node_type(entry); + unsigned int i; + + mt_dump_range(min, max, depth, format); + + pr_cont("node %p depth %d type %d parent %p", node, depth, type, + node ? node->parent : NULL); + switch (type) { + case maple_dense: + pr_cont("\n"); + for (i = 0; i < MAPLE_NODE_SLOTS; i++) { + if (min + i > max) + pr_cont("OUT OF RANGE: "); + mt_dump_entry(mt_slot(mt, node->slot, i), + min + i, min + i, depth, format); + } + break; + case maple_leaf_64: + case maple_range_64: + mt_dump_range64(mt, entry, min, max, depth, format); + break; + case maple_arange_64: + mt_dump_arange64(mt, entry, min, max, depth, format); + break; + + default: + pr_cont(" UNKNOWN TYPE\n"); + } +} + +void mt_dump(const struct maple_tree *mt, enum mt_dump_format format) +{ + void *entry = rcu_dereference_check(mt->ma_root, mt_locked(mt)); + + pr_info("maple_tree(%p) flags %X, height %u root %p\n", + mt, mt->ma_flags, mt_height(mt), entry); + if (!xa_is_node(entry)) + mt_dump_entry(entry, 0, 0, 0, format); + else if (entry) + mt_dump_node(mt, entry, 0, mt_node_max(entry), 0, format); +} +EXPORT_SYMBOL_GPL(mt_dump); + +/* + * Calculate the maximum gap in a node and check if that's what is reported in + * the parent (unless root). + */ +static void mas_validate_gaps(struct ma_state *mas) +{ + struct maple_enode *mte = mas->node; + struct maple_node *p_mn, *node = mte_to_node(mte); + enum maple_type mt = mte_node_type(mas->node); + unsigned long gap = 0, max_gap = 0; + unsigned long p_end, p_start = mas->min; + unsigned char p_slot, offset; + unsigned long *gaps = NULL; + unsigned long *pivots = ma_pivots(node, mt); + unsigned int i; + + if (ma_is_dense(mt)) { + for (i = 0; i < mt_slot_count(mte); i++) { + if (mas_get_slot(mas, i)) { + if (gap > max_gap) + max_gap = gap; + gap = 0; + continue; + } + gap++; + } + goto counted; + } + + gaps = ma_gaps(node, mt); + for (i = 0; i < mt_slot_count(mte); i++) { + p_end = mas_safe_pivot(mas, pivots, i, mt); + + if (!gaps) { + if (!mas_get_slot(mas, i)) + gap = p_end - p_start + 1; + } else { + void *entry = mas_get_slot(mas, i); + + gap = gaps[i]; + MT_BUG_ON(mas->tree, !entry); + + if (gap > p_end - p_start + 1) { + pr_err("%p[%u] %lu >= %lu - %lu + 1 (%lu)\n", + mas_mn(mas), i, gap, p_end, p_start, + p_end - p_start + 1); + MT_BUG_ON(mas->tree, gap > p_end - p_start + 1); + } + } + + if (gap > max_gap) + max_gap = gap; + + p_start = p_end + 1; + if (p_end >= mas->max) + break; + } + +counted: + if (mt == maple_arange_64) { + MT_BUG_ON(mas->tree, !gaps); + offset = ma_meta_gap(node); + if (offset > i) { + pr_err("gap offset %p[%u] is invalid\n", node, offset); + MT_BUG_ON(mas->tree, 1); + } + + if (gaps[offset] != max_gap) { + pr_err("gap %p[%u] is not the largest gap %lu\n", + node, offset, max_gap); + MT_BUG_ON(mas->tree, 1); + } + + for (i++ ; i < mt_slot_count(mte); i++) { + if (gaps[i] != 0) { + pr_err("gap %p[%u] beyond node limit != 0\n", + node, i); + MT_BUG_ON(mas->tree, 1); + } + } + } + + if (mte_is_root(mte)) + return; + + p_slot = mte_parent_slot(mas->node); + p_mn = mte_parent(mte); + MT_BUG_ON(mas->tree, max_gap > mas->max); + if (ma_gaps(p_mn, mas_parent_type(mas, mte))[p_slot] != max_gap) { + pr_err("gap %p[%u] != %lu\n", p_mn, p_slot, max_gap); + mt_dump(mas->tree, mt_dump_hex); + MT_BUG_ON(mas->tree, 1); + } +} + +static void mas_validate_parent_slot(struct ma_state *mas) +{ + struct maple_node *parent; + struct maple_enode *node; + enum maple_type p_type; + unsigned char p_slot; + void __rcu **slots; + int i; + + if (mte_is_root(mas->node)) + return; + + p_slot = mte_parent_slot(mas->node); + p_type = mas_parent_type(mas, mas->node); + parent = mte_parent(mas->node); + slots = ma_slots(parent, p_type); + MT_BUG_ON(mas->tree, mas_mn(mas) == parent); + + /* Check prev/next parent slot for duplicate node entry */ + + for (i = 0; i < mt_slots[p_type]; i++) { + node = mas_slot(mas, slots, i); + if (i == p_slot) { + if (node != mas->node) + pr_err("parent %p[%u] does not have %p\n", + parent, i, mas_mn(mas)); + MT_BUG_ON(mas->tree, node != mas->node); + } else if (node == mas->node) { + pr_err("Invalid child %p at parent %p[%u] p_slot %u\n", + mas_mn(mas), parent, i, p_slot); + MT_BUG_ON(mas->tree, node == mas->node); + } + } +} + +static void mas_validate_child_slot(struct ma_state *mas) +{ + enum maple_type type = mte_node_type(mas->node); + void __rcu **slots = ma_slots(mte_to_node(mas->node), type); + unsigned long *pivots = ma_pivots(mte_to_node(mas->node), type); + struct maple_enode *child; + unsigned char i; + + if (mte_is_leaf(mas->node)) + return; + + for (i = 0; i < mt_slots[type]; i++) { + child = mas_slot(mas, slots, i); + + if (!child) { + pr_err("Non-leaf node lacks child at %p[%u]\n", + mas_mn(mas), i); + MT_BUG_ON(mas->tree, 1); + } + + if (mte_parent_slot(child) != i) { + pr_err("Slot error at %p[%u]: child %p has pslot %u\n", + mas_mn(mas), i, mte_to_node(child), + mte_parent_slot(child)); + MT_BUG_ON(mas->tree, 1); + } + + if (mte_parent(child) != mte_to_node(mas->node)) { + pr_err("child %p has parent %p not %p\n", + mte_to_node(child), mte_parent(child), + mte_to_node(mas->node)); + MT_BUG_ON(mas->tree, 1); + } + + if (i < mt_pivots[type] && pivots[i] == mas->max) + break; + } +} + +/* + * Validate all pivots are within mas->min and mas->max, check metadata ends + * where the maximum ends and ensure there is no slots or pivots set outside of + * the end of the data. + */ +static void mas_validate_limits(struct ma_state *mas) +{ + int i; + unsigned long prev_piv = 0; + enum maple_type type = mte_node_type(mas->node); + void __rcu **slots = ma_slots(mte_to_node(mas->node), type); + unsigned long *pivots = ma_pivots(mas_mn(mas), type); + + for (i = 0; i < mt_slots[type]; i++) { + unsigned long piv; + + piv = mas_safe_pivot(mas, pivots, i, type); + + if (!piv && (i != 0)) { + pr_err("Missing node limit pivot at %p[%u]", + mas_mn(mas), i); + MAS_WARN_ON(mas, 1); + } + + if (prev_piv > piv) { + pr_err("%p[%u] piv %lu < prev_piv %lu\n", + mas_mn(mas), i, piv, prev_piv); + MAS_WARN_ON(mas, piv < prev_piv); + } + + if (piv < mas->min) { + pr_err("%p[%u] %lu < %lu\n", mas_mn(mas), i, + piv, mas->min); + MAS_WARN_ON(mas, piv < mas->min); + } + if (piv > mas->max) { + pr_err("%p[%u] %lu > %lu\n", mas_mn(mas), i, + piv, mas->max); + MAS_WARN_ON(mas, piv > mas->max); + } + prev_piv = piv; + if (piv == mas->max) + break; + } + + if (mas_data_end(mas) != i) { + pr_err("node%p: data_end %u != the last slot offset %u\n", + mas_mn(mas), mas_data_end(mas), i); + MT_BUG_ON(mas->tree, 1); + } + + for (i += 1; i < mt_slots[type]; i++) { + void *entry = mas_slot(mas, slots, i); + + if (entry && (i != mt_slots[type] - 1)) { + pr_err("%p[%u] should not have entry %p\n", mas_mn(mas), + i, entry); + MT_BUG_ON(mas->tree, entry != NULL); + } + + if (i < mt_pivots[type]) { + unsigned long piv = pivots[i]; + + if (!piv) + continue; + + pr_err("%p[%u] should not have piv %lu\n", + mas_mn(mas), i, piv); + MAS_WARN_ON(mas, i < mt_pivots[type] - 1); + } + } +} + +static void mt_validate_nulls(struct maple_tree *mt) +{ + void *entry, *last = (void *)1; + unsigned char offset = 0; + void __rcu **slots; + MA_STATE(mas, mt, 0, 0); + + mas_start(&mas); + if (mas_is_none(&mas) || (mas_is_ptr(&mas))) + return; + + while (!mte_is_leaf(mas.node)) + mas_descend(&mas); + + slots = ma_slots(mte_to_node(mas.node), mte_node_type(mas.node)); + do { + entry = mas_slot(&mas, slots, offset); + if (!last && !entry) { + pr_err("Sequential nulls end at %p[%u]\n", + mas_mn(&mas), offset); + } + MT_BUG_ON(mt, !last && !entry); + last = entry; + if (offset == mas_data_end(&mas)) { + mas_next_node(&mas, mas_mn(&mas), ULONG_MAX); + if (mas_is_overflow(&mas)) + return; + offset = 0; + slots = ma_slots(mte_to_node(mas.node), + mte_node_type(mas.node)); + } else { + offset++; + } + + } while (!mas_is_overflow(&mas)); +} + +/* + * validate a maple tree by checking: + * 1. The limits (pivots are within mas->min to mas->max) + * 2. The gap is correctly set in the parents + */ +void mt_validate(struct maple_tree *mt) +{ + unsigned char end; + + MA_STATE(mas, mt, 0, 0); + rcu_read_lock(); + mas_start(&mas); + if (!mas_is_active(&mas)) + goto done; + + while (!mte_is_leaf(mas.node)) + mas_descend(&mas); + + while (!mas_is_overflow(&mas)) { + MAS_WARN_ON(&mas, mte_dead_node(mas.node)); + end = mas_data_end(&mas); + if (MAS_WARN_ON(&mas, (end < mt_min_slot_count(mas.node)) && + (mas.max != ULONG_MAX))) { + pr_err("Invalid size %u of %p\n", end, mas_mn(&mas)); + } + + mas_validate_parent_slot(&mas); + mas_validate_limits(&mas); + mas_validate_child_slot(&mas); + if (mt_is_alloc(mt)) + mas_validate_gaps(&mas); + mas_dfs_postorder(&mas, ULONG_MAX); + } + mt_validate_nulls(mt); +done: + rcu_read_unlock(); + +} +EXPORT_SYMBOL_GPL(mt_validate); + +void mas_dump(const struct ma_state *mas) +{ + pr_err("MAS: tree=%p enode=%p ", mas->tree, mas->node); + switch (mas->status) { + case ma_active: + pr_err("(ma_active)"); + break; + case ma_none: + pr_err("(ma_none)"); + break; + case ma_root: + pr_err("(ma_root)"); + break; + case ma_start: + pr_err("(ma_start) "); + break; + case ma_pause: + pr_err("(ma_pause) "); + break; + case ma_overflow: + pr_err("(ma_overflow) "); + break; + case ma_underflow: + pr_err("(ma_underflow) "); + break; + case ma_error: + pr_err("(ma_error) "); + break; + } + + pr_err("[%u/%u] index=%lx last=%lx\n", mas->offset, mas->end, + mas->index, mas->last); + pr_err(" min=%lx max=%lx alloc=%p, depth=%u, flags=%x\n", + mas->min, mas->max, mas->alloc, mas->depth, mas->mas_flags); + if (mas->index > mas->last) + pr_err("Check index & last\n"); +} +EXPORT_SYMBOL_GPL(mas_dump); + +void mas_wr_dump(const struct ma_wr_state *wr_mas) +{ + pr_err("WR_MAS: node=%p r_min=%lx r_max=%lx\n", + wr_mas->node, wr_mas->r_min, wr_mas->r_max); + pr_err(" type=%u off_end=%u, node_end=%u, end_piv=%lx\n", + wr_mas->type, wr_mas->offset_end, wr_mas->mas->end, + wr_mas->end_piv); +} +EXPORT_SYMBOL_GPL(mas_wr_dump); + +#endif /* CONFIG_DEBUG_MAPLE_TREE */ |