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-rw-r--r--lib/xarray.c323
1 files changed, 286 insertions, 37 deletions
diff --git a/lib/xarray.c b/lib/xarray.c
index 446b956c9188..39f07bfc4dcc 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1,7 +1,8 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* XArray implementation
- * Copyright (c) 2017 Microsoft Corporation
+ * Copyright (c) 2017-2018 Microsoft Corporation
+ * Copyright (c) 2018-2020 Oracle
* Author: Matthew Wilcox <willy@infradead.org>
*/
@@ -11,6 +12,8 @@
#include <linux/slab.h>
#include <linux/xarray.h>
+#include "radix-tree.h"
+
/*
* Coding conventions in this file:
*
@@ -156,7 +159,7 @@ static void xas_move_index(struct xa_state *xas, unsigned long offset)
xas->xa_index += offset << shift;
}
-static void xas_advance(struct xa_state *xas)
+static void xas_next_offset(struct xa_state *xas)
{
xas->xa_offset++;
xas_move_index(xas, xas->xa_offset);
@@ -203,9 +206,11 @@ static void *xas_descend(struct xa_state *xas, struct xa_node *node)
void *entry = xa_entry(xas->xa, node, offset);
xas->xa_node = node;
- if (xa_is_sibling(entry)) {
+ while (xa_is_sibling(entry)) {
offset = xa_to_sibling(entry);
entry = xa_entry(xas->xa, node, offset);
+ if (node->shift && xa_is_node(entry))
+ entry = XA_RETRY_ENTRY;
}
xas->xa_offset = offset;
@@ -244,10 +249,6 @@ void *xas_load(struct xa_state *xas)
}
EXPORT_SYMBOL_GPL(xas_load);
-/* Move the radix tree node cache here */
-extern struct kmem_cache *radix_tree_node_cachep;
-extern void radix_tree_node_rcu_free(struct rcu_head *head);
-
#define XA_RCU_FREE ((struct xarray *)1)
static void xa_node_free(struct xa_node *node)
@@ -261,17 +262,19 @@ static void xa_node_free(struct xa_node *node)
* xas_destroy() - Free any resources allocated during the XArray operation.
* @xas: XArray operation state.
*
- * This function is now internal-only.
+ * Most users will not need to call this function; it is called for you
+ * by xas_nomem().
*/
-static void xas_destroy(struct xa_state *xas)
+void xas_destroy(struct xa_state *xas)
{
- struct xa_node *node = xas->xa_alloc;
+ struct xa_node *next, *node = xas->xa_alloc;
- if (!node)
- return;
- XA_NODE_BUG_ON(node, !list_empty(&node->private_list));
- kmem_cache_free(radix_tree_node_cachep, node);
- xas->xa_alloc = NULL;
+ while (node) {
+ XA_NODE_BUG_ON(node, !list_empty(&node->private_list));
+ next = rcu_dereference_raw(node->parent);
+ radix_tree_node_rcu_free(&node->rcu_head);
+ xas->xa_alloc = node = next;
+ }
}
/**
@@ -300,9 +303,10 @@ bool xas_nomem(struct xa_state *xas, gfp_t gfp)
}
if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT)
gfp |= __GFP_ACCOUNT;
- xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp);
+ xas->xa_alloc = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp);
if (!xas->xa_alloc)
return false;
+ xas->xa_alloc->parent = NULL;
XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list));
xas->xa_node = XAS_RESTART;
return true;
@@ -331,13 +335,14 @@ static bool __xas_nomem(struct xa_state *xas, gfp_t gfp)
gfp |= __GFP_ACCOUNT;
if (gfpflags_allow_blocking(gfp)) {
xas_unlock_type(xas, lock_type);
- xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp);
+ xas->xa_alloc = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp);
xas_lock_type(xas, lock_type);
} else {
- xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp);
+ xas->xa_alloc = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp);
}
if (!xas->xa_alloc)
return false;
+ xas->xa_alloc->parent = NULL;
XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list));
xas->xa_node = XAS_RESTART;
return true;
@@ -367,7 +372,7 @@ static void *xas_alloc(struct xa_state *xas, unsigned int shift)
if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT)
gfp |= __GFP_ACCOUNT;
- node = kmem_cache_alloc(radix_tree_node_cachep, gfp);
+ node = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp);
if (!node) {
xas_set_err(xas, -ENOMEM);
return NULL;
@@ -402,7 +407,7 @@ static unsigned long xas_size(const struct xa_state *xas)
/*
* Use this to calculate the maximum index that will need to be created
* in order to add the entry described by @xas. Because we cannot store a
- * multiple-index entry at index 0, the calculation is a little more complex
+ * multi-index entry at index 0, the calculation is a little more complex
* than you might expect.
*/
static unsigned long xas_max(struct xa_state *xas)
@@ -702,7 +707,7 @@ void xas_create_range(struct xa_state *xas)
unsigned char shift = xas->xa_shift;
unsigned char sibs = xas->xa_sibs;
- xas->xa_index |= ((sibs + 1) << shift) - 1;
+ xas->xa_index |= ((sibs + 1UL) << shift) - 1;
if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift)
xas->xa_offset |= sibs;
xas->xa_shift = 0;
@@ -718,6 +723,8 @@ void xas_create_range(struct xa_state *xas)
for (;;) {
struct xa_node *node = xas->xa_node;
+ if (node->shift >= shift)
+ break;
xas->xa_node = xa_parent_locked(xas->xa, node);
xas->xa_offset = node->offset - 1;
if (node->offset != 0)
@@ -945,6 +952,156 @@ void xas_init_marks(const struct xa_state *xas)
}
EXPORT_SYMBOL_GPL(xas_init_marks);
+#ifdef CONFIG_XARRAY_MULTI
+static unsigned int node_get_marks(struct xa_node *node, unsigned int offset)
+{
+ unsigned int marks = 0;
+ xa_mark_t mark = XA_MARK_0;
+
+ for (;;) {
+ if (node_get_mark(node, offset, mark))
+ marks |= 1 << (__force unsigned int)mark;
+ if (mark == XA_MARK_MAX)
+ break;
+ mark_inc(mark);
+ }
+
+ return marks;
+}
+
+static void node_set_marks(struct xa_node *node, unsigned int offset,
+ struct xa_node *child, unsigned int marks)
+{
+ xa_mark_t mark = XA_MARK_0;
+
+ for (;;) {
+ if (marks & (1 << (__force unsigned int)mark)) {
+ node_set_mark(node, offset, mark);
+ if (child)
+ node_mark_all(child, mark);
+ }
+ if (mark == XA_MARK_MAX)
+ break;
+ mark_inc(mark);
+ }
+}
+
+/**
+ * xas_split_alloc() - Allocate memory for splitting an entry.
+ * @xas: XArray operation state.
+ * @entry: New entry which will be stored in the array.
+ * @order: Current entry order.
+ * @gfp: Memory allocation flags.
+ *
+ * This function should be called before calling xas_split().
+ * If necessary, it will allocate new nodes (and fill them with @entry)
+ * to prepare for the upcoming split of an entry of @order size into
+ * entries of the order stored in the @xas.
+ *
+ * Context: May sleep if @gfp flags permit.
+ */
+void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order,
+ gfp_t gfp)
+{
+ unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1;
+ unsigned int mask = xas->xa_sibs;
+
+ /* XXX: no support for splitting really large entries yet */
+ if (WARN_ON(xas->xa_shift + 2 * XA_CHUNK_SHIFT < order))
+ goto nomem;
+ if (xas->xa_shift + XA_CHUNK_SHIFT > order)
+ return;
+
+ do {
+ unsigned int i;
+ void *sibling = NULL;
+ struct xa_node *node;
+
+ node = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp);
+ if (!node)
+ goto nomem;
+ node->array = xas->xa;
+ for (i = 0; i < XA_CHUNK_SIZE; i++) {
+ if ((i & mask) == 0) {
+ RCU_INIT_POINTER(node->slots[i], entry);
+ sibling = xa_mk_sibling(i);
+ } else {
+ RCU_INIT_POINTER(node->slots[i], sibling);
+ }
+ }
+ RCU_INIT_POINTER(node->parent, xas->xa_alloc);
+ xas->xa_alloc = node;
+ } while (sibs-- > 0);
+
+ return;
+nomem:
+ xas_destroy(xas);
+ xas_set_err(xas, -ENOMEM);
+}
+EXPORT_SYMBOL_GPL(xas_split_alloc);
+
+/**
+ * xas_split() - Split a multi-index entry into smaller entries.
+ * @xas: XArray operation state.
+ * @entry: New entry to store in the array.
+ * @order: Current entry order.
+ *
+ * The size of the new entries is set in @xas. The value in @entry is
+ * copied to all the replacement entries.
+ *
+ * Context: Any context. The caller should hold the xa_lock.
+ */
+void xas_split(struct xa_state *xas, void *entry, unsigned int order)
+{
+ unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1;
+ unsigned int offset, marks;
+ struct xa_node *node;
+ void *curr = xas_load(xas);
+ int values = 0;
+
+ node = xas->xa_node;
+ if (xas_top(node))
+ return;
+
+ marks = node_get_marks(node, xas->xa_offset);
+
+ offset = xas->xa_offset + sibs;
+ do {
+ if (xas->xa_shift < node->shift) {
+ struct xa_node *child = xas->xa_alloc;
+
+ xas->xa_alloc = rcu_dereference_raw(child->parent);
+ child->shift = node->shift - XA_CHUNK_SHIFT;
+ child->offset = offset;
+ child->count = XA_CHUNK_SIZE;
+ child->nr_values = xa_is_value(entry) ?
+ XA_CHUNK_SIZE : 0;
+ RCU_INIT_POINTER(child->parent, node);
+ node_set_marks(node, offset, child, marks);
+ rcu_assign_pointer(node->slots[offset],
+ xa_mk_node(child));
+ if (xa_is_value(curr))
+ values--;
+ xas_update(xas, child);
+ } else {
+ unsigned int canon = offset - xas->xa_sibs;
+
+ node_set_marks(node, canon, NULL, marks);
+ rcu_assign_pointer(node->slots[canon], entry);
+ while (offset > canon)
+ rcu_assign_pointer(node->slots[offset--],
+ xa_mk_sibling(canon));
+ values += (xa_is_value(entry) - xa_is_value(curr)) *
+ (xas->xa_sibs + 1);
+ }
+ } while (offset-- > xas->xa_offset);
+
+ node->nr_values += values;
+ xas_update(xas, node);
+}
+EXPORT_SYMBOL_GPL(xas_split);
+#endif
+
/**
* xas_pause() - Pause a walk to drop a lock.
* @xas: XArray operation state.
@@ -967,17 +1124,19 @@ void xas_pause(struct xa_state *xas)
if (xas_invalid(xas))
return;
+ xas->xa_node = XAS_RESTART;
if (node) {
- unsigned int offset = xas->xa_offset;
+ unsigned long offset = xas->xa_offset;
while (++offset < XA_CHUNK_SIZE) {
if (!xa_is_sibling(xa_entry(xas->xa, node, offset)))
break;
}
xas->xa_index += (offset - xas->xa_offset) << node->shift;
+ if (xas->xa_index == 0)
+ xas->xa_node = XAS_BOUNDS;
} else {
xas->xa_index++;
}
- xas->xa_node = XAS_RESTART;
}
EXPORT_SYMBOL_GPL(xas_pause);
@@ -994,6 +1153,8 @@ void *__xas_prev(struct xa_state *xas)
if (!xas_frozen(xas->xa_node))
xas->xa_index--;
+ if (!xas->xa_node)
+ return set_bounds(xas);
if (xas_not_node(xas->xa_node))
return xas_load(xas);
@@ -1031,6 +1192,8 @@ void *__xas_next(struct xa_state *xas)
if (!xas_frozen(xas->xa_node))
xas->xa_index++;
+ if (!xas->xa_node)
+ return set_bounds(xas);
if (xas_not_node(xas->xa_node))
return xas_load(xas);
@@ -1075,13 +1238,15 @@ void *xas_find(struct xa_state *xas, unsigned long max)
{
void *entry;
- if (xas_error(xas))
+ if (xas_error(xas) || xas->xa_node == XAS_BOUNDS)
return NULL;
+ if (xas->xa_index > max)
+ return set_bounds(xas);
if (!xas->xa_node) {
xas->xa_index = 1;
return set_bounds(xas);
- } else if (xas_top(xas->xa_node)) {
+ } else if (xas->xa_node == XAS_RESTART) {
entry = xas_load(xas);
if (entry || xas_not_node(xas->xa_node))
return entry;
@@ -1090,7 +1255,7 @@ void *xas_find(struct xa_state *xas, unsigned long max)
xas->xa_offset = ((xas->xa_index - 1) & XA_CHUNK_MASK) + 1;
}
- xas_advance(xas);
+ xas_next_offset(xas);
while (xas->xa_node && (xas->xa_index <= max)) {
if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) {
@@ -1108,7 +1273,7 @@ void *xas_find(struct xa_state *xas, unsigned long max)
if (entry && !xa_is_sibling(entry))
return entry;
- xas_advance(xas);
+ xas_next_offset(xas);
}
if (!xas->xa_node)
@@ -1146,6 +1311,8 @@ void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark)
if (xas_error(xas))
return NULL;
+ if (xas->xa_index > max)
+ goto max;
if (!xas->xa_node) {
xas->xa_index = 1;
@@ -1197,6 +1364,8 @@ void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark)
}
entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);
+ if (!entry && !(xa_track_free(xas->xa) && mark == XA_FREE_MARK))
+ continue;
if (!xa_is_node(entry))
return entry;
xas->xa_node = xa_to_node(entry);
@@ -1394,7 +1563,7 @@ EXPORT_SYMBOL(__xa_store);
* @gfp: Memory allocation flags.
*
* After this function returns, loads from this index will return @entry.
- * Storing into an existing multislot entry updates the entry of every index.
+ * Storing into an existing multi-index entry updates the entry of every index.
* The marks associated with @index are unaffected unless @entry is %NULL.
*
* Context: Any context. Takes and releases the xa_lock.
@@ -1536,7 +1705,7 @@ static void xas_set_range(struct xa_state *xas, unsigned long first,
*
* After this function returns, loads from any index between @first and @last,
* inclusive will return @entry.
- * Storing into an existing multislot entry updates the entry of every index.
+ * Storing into an existing multi-index entry updates the entry of every index.
* The marks associated with @index are unaffected unless @entry is %NULL.
*
* Context: Process context. Takes and releases the xa_lock. May sleep
@@ -1579,6 +1748,46 @@ unlock:
return xas_result(&xas, NULL);
}
EXPORT_SYMBOL(xa_store_range);
+
+/**
+ * xa_get_order() - Get the order of an entry.
+ * @xa: XArray.
+ * @index: Index of the entry.
+ *
+ * Return: A number between 0 and 63 indicating the order of the entry.
+ */
+int xa_get_order(struct xarray *xa, unsigned long index)
+{
+ XA_STATE(xas, xa, index);
+ void *entry;
+ int order = 0;
+
+ rcu_read_lock();
+ entry = xas_load(&xas);
+
+ if (!entry)
+ goto unlock;
+
+ if (!xas.xa_node)
+ goto unlock;
+
+ for (;;) {
+ unsigned int slot = xas.xa_offset + (1 << order);
+
+ if (slot >= XA_CHUNK_SIZE)
+ break;
+ if (!xa_is_sibling(xas.xa_node->slots[slot]))
+ break;
+ order++;
+ }
+
+ order += xas.xa_node->shift;
+unlock:
+ rcu_read_unlock();
+
+ return order;
+}
+EXPORT_SYMBOL(xa_get_order);
#endif /* CONFIG_XARRAY_MULTI */
/**
@@ -1593,6 +1802,9 @@ EXPORT_SYMBOL(xa_store_range);
* stores the index into the @id pointer, then stores the entry at
* that index. A concurrent lookup will not see an uninitialised @id.
*
+ * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set
+ * in xa_init_flags().
+ *
* Context: Any context. Expects xa_lock to be held on entry. May
* release and reacquire xa_lock if @gfp flags permit.
* Return: 0 on success, -ENOMEM if memory could not be allocated or
@@ -1641,6 +1853,9 @@ EXPORT_SYMBOL(__xa_alloc);
* The search for an empty entry will start at @next and will wrap
* around if necessary.
*
+ * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set
+ * in xa_init_flags().
+ *
* Context: Any context. Expects xa_lock to be held on entry. May
* release and reacquire xa_lock if @gfp flags permit.
* Return: 0 if the allocation succeeded without wrapping. 1 if the
@@ -1820,6 +2035,18 @@ void *xa_find(struct xarray *xa, unsigned long *indexp,
}
EXPORT_SYMBOL(xa_find);
+static bool xas_sibling(struct xa_state *xas)
+{
+ struct xa_node *node = xas->xa_node;
+ unsigned long mask;
+
+ if (!IS_ENABLED(CONFIG_XARRAY_MULTI) || !node)
+ return false;
+ mask = (XA_CHUNK_SIZE << node->shift) - 1;
+ return (xas->xa_index & mask) >
+ ((unsigned long)xas->xa_offset << node->shift);
+}
+
/**
* xa_find_after() - Search the XArray for a present entry.
* @xa: XArray.
@@ -1843,21 +2070,20 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp,
XA_STATE(xas, xa, *indexp + 1);
void *entry;
+ if (xas.xa_index == 0)
+ return NULL;
+
rcu_read_lock();
for (;;) {
if ((__force unsigned int)filter < XA_MAX_MARKS)
entry = xas_find_marked(&xas, max, filter);
else
entry = xas_find(&xas, max);
- if (xas.xa_node == XAS_BOUNDS)
+
+ if (xas_invalid(&xas))
break;
- if (xas.xa_shift) {
- if (xas.xa_index & ((1UL << xas.xa_shift) - 1))
- continue;
- } else {
- if (xas.xa_offset < (xas.xa_index & XA_CHUNK_MASK))
- continue;
- }
+ if (xas_sibling(&xas))
+ continue;
if (!xas_retry(&xas, entry))
break;
}
@@ -1950,6 +2176,29 @@ unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start,
EXPORT_SYMBOL(xa_extract);
/**
+ * xa_delete_node() - Private interface for workingset code.
+ * @node: Node to be removed from the tree.
+ * @update: Function to call to update ancestor nodes.
+ *
+ * Context: xa_lock must be held on entry and will not be released.
+ */
+void xa_delete_node(struct xa_node *node, xa_update_node_t update)
+{
+ struct xa_state xas = {
+ .xa = node->array,
+ .xa_index = (unsigned long)node->offset <<
+ (node->shift + XA_CHUNK_SHIFT),
+ .xa_shift = node->shift + XA_CHUNK_SHIFT,
+ .xa_offset = node->offset,
+ .xa_node = xa_parent_locked(node->array, node),
+ .xa_update = update,
+ };
+
+ xas_store(&xas, NULL);
+}
+EXPORT_SYMBOL_GPL(xa_delete_node); /* For the benefit of the test suite */
+
+/**
* xa_destroy() - Free all internal data structures.
* @xa: XArray.
*
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-30 16:07:30 +0000