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From 53d06c5161e208d90d4de21079c2447a0c0b25b6 Mon Sep 17 00:00:00 2001
From: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Date: Wed, 30 Nov 2016 17:31:04 -0500
Subject: [PATCH 1564/4131] drm/amdkfd: Remove assoc_array dependency for IPC
Use hash table instead. This makes IPC support compatible with older
kernels
Change-Id: Ia099f7d99d96dd3741d1ebfa3c2c1c7498ec1a73
Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
---
drivers/gpu/drm/amd/amdkfd/kfd_ipc.c | 147 ++++++++++-------------------------
drivers/gpu/drm/amd/amdkfd/kfd_ipc.h | 5 +-
2 files changed, 42 insertions(+), 110 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c
index 5391f8a..62aaeac 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.c
@@ -21,100 +21,29 @@
*/
#include <linux/dma-buf.h>
-#include <linux/assoc_array.h>
#include <linux/slab.h>
#include <linux/random.h>
#include "kfd_ipc.h"
#include "kfd_priv.h"
-/**
- * The assoc_array data structure provides a non-intrusive
- * key-value data store mechanism where the key can be
- * arbitratily long (and value is just a void*).
- *
- * This provides us good control for managing IPC handle length
- * in case we require extra entropy to discourage handle-guessing.
- */
-static struct assoc_array ipc_handles;
-
-static unsigned long ipc_get_key_chunk(const void *index_key, int level)
-{
- unsigned long chunk;
- int index = level/ASSOC_ARRAY_KEY_CHUNK_SIZE;
-
- /* no more data, but we can't fail */
- if (level > IPC_KEY_SIZE_BYTES*8)
- return 0;
-
- chunk = ((unsigned long *)index_key)[index];
- return chunk;
-}
-
-static unsigned long ipc_get_object_key_chunk(const void *object, int level)
-{
- const struct kfd_ipc_obj *obj = (const struct kfd_ipc_obj *)object;
-
- return ipc_get_key_chunk(&obj->key, level);
-}
-
-static bool ipc_compare_object(const void *object, const void *index_key)
-{
- const struct kfd_ipc_obj *obj = (const struct kfd_ipc_obj *)object;
+#define KFD_IPC_HASH_TABLE_SIZE_SHIFT 4
+#define KFD_IPC_HASH_TABLE_SIZE_MASK ((1 << KFD_IPC_HASH_TABLE_SIZE_SHIFT) - 1)
- return memcmp(obj->key, index_key, IPC_KEY_SIZE_BYTES) == 0;
-}
+static struct kfd_ipc_handles {
+ DECLARE_HASHTABLE(handles, KFD_IPC_HASH_TABLE_SIZE_SHIFT);
+ struct mutex lock;
+} kfd_ipc_handles;
-/*
- * Compare the index keys of a pair of objects and determine the bit position
- * at which they differ - if they differ.
+/* Since, handles are random numbers, it can be used directly as hashing key.
+ * The least 4 bits of the handle are used as key. However, during import all
+ * 128 bits of the handle are checked to prevent handle snooping.
*/
-static int ipc_diff_objects(const void *object, const void *index_key)
-{
- const struct kfd_ipc_obj *obj = (const struct kfd_ipc_obj *)object;
- int i;
+#define HANDLE_TO_KEY(sh) ((*(uint64_t *)sh) & KFD_IPC_HASH_TABLE_SIZE_MASK)
- /* naive linear byte search */
- for (i = 0; i < IPC_KEY_SIZE_BYTES; ++i) {
- if (obj->key[i] != ((char *)index_key)[i])
- return i * 8;
- }
-
- return -1;
-}
-
-/*
- * Free an object after stripping the ipc flag off of the pointer.
- */
-static void ipc_free_object(void *object)
-{
-}
-
-/*
- * Operations for ipc management by the index-tree routines.
- */
-static const struct assoc_array_ops ipc_assoc_array_ops = {
- .get_key_chunk = ipc_get_key_chunk,
- .get_object_key_chunk = ipc_get_object_key_chunk,
- .compare_object = ipc_compare_object,
- .diff_objects = ipc_diff_objects,
- .free_object = ipc_free_object,
-};
-
-static void ipc_gen_key(void *buf)
-{
- uint32_t *key = (uint32_t *) buf;
-
- get_random_bytes(buf, IPC_KEY_SIZE_BYTES);
-
- /* last byte of the key is reserved */
- key[3] = (key[3] & ~0xFF) | 0x1;
-}
-
-static int ipc_store_insert(void *val, void *key, struct kfd_ipc_obj **ipc_obj)
+static int ipc_store_insert(void *val, void *sh, struct kfd_ipc_obj **ipc_obj)
{
struct kfd_ipc_obj *obj;
- struct assoc_array_edit *edit;
obj = kmalloc(sizeof(struct kfd_ipc_obj), GFP_KERNEL);
if (!obj)
@@ -129,16 +58,14 @@ static int ipc_store_insert(void *val, void *key, struct kfd_ipc_obj **ipc_obj)
*/
kref_init(&obj->ref);
obj->data = val;
- ipc_gen_key(obj->key);
+ get_random_bytes(obj->share_handle, sizeof(obj->share_handle));
- memcpy(key, obj->key, IPC_KEY_SIZE_BYTES);
+ memcpy(sh, obj->share_handle, sizeof(obj->share_handle));
- pr_debug("ipc: val::%p ref:%p\n", val, &obj->ref);
-
- edit = assoc_array_insert(&ipc_handles,
- &ipc_assoc_array_ops,
- obj->key, obj);
- assoc_array_apply_edit(edit);
+ mutex_lock(&kfd_ipc_handles.lock);
+ hlist_add_head(&obj->node,
+ &kfd_ipc_handles.handles[HANDLE_TO_KEY(obj->share_handle)]);
+ mutex_unlock(&kfd_ipc_handles.lock);
if (ipc_obj)
*ipc_obj = obj;
@@ -146,22 +73,16 @@ static int ipc_store_insert(void *val, void *key, struct kfd_ipc_obj **ipc_obj)
return 0;
}
-static int ipc_store_remove(void *key)
-{
- struct assoc_array_edit *edit;
-
- edit = assoc_array_delete(&ipc_handles, &ipc_assoc_array_ops, key);
- assoc_array_apply_edit(edit);
- return 0;
-}
-
static void ipc_obj_release(struct kref *r)
{
struct kfd_ipc_obj *obj;
obj = container_of(r, struct kfd_ipc_obj, ref);
- ipc_store_remove(obj->key);
+ mutex_lock(&kfd_ipc_handles.lock);
+ hash_del(&obj->node);
+ mutex_unlock(&kfd_ipc_handles.lock);
+
dma_buf_put(obj->data);
kfree(obj);
}
@@ -179,7 +100,8 @@ void ipc_obj_put(struct kfd_ipc_obj **obj)
int kfd_ipc_init(void)
{
- assoc_array_init(&ipc_handles);
+ mutex_init(&kfd_ipc_handles.lock);
+ hash_init(kfd_ipc_handles.handles);
return 0;
}
@@ -262,11 +184,22 @@ int kfd_ipc_import_handle(struct kfd_dev *dev, struct kfd_process *p,
uint64_t *mmap_offset)
{
int r;
- struct kfd_ipc_obj *found;
+ struct kfd_ipc_obj *entry, *found = NULL;
+
+ mutex_lock(&kfd_ipc_handles.lock);
+ /* Convert the user provided handle to hash key and search only in that
+ * bucket
+ */
+ hlist_for_each_entry(entry,
+ &kfd_ipc_handles.handles[HANDLE_TO_KEY(share_handle)], node) {
+ if (!memcmp(entry->share_handle, share_handle,
+ sizeof(entry->share_handle))) {
+ found = entry;
+ break;
+ }
+ }
+ mutex_unlock(&kfd_ipc_handles.lock);
- found = assoc_array_find(&ipc_handles,
- &ipc_assoc_array_ops,
- share_handle);
if (!found)
return -EINVAL;
ipc_obj_get(found);
@@ -316,8 +249,8 @@ int kfd_ipc_export_as_handle(struct kfd_dev *dev, struct kfd_process *p,
return -EINVAL;
}
if (kfd_bo->kfd_ipc_obj) {
- memcpy(ipc_handle, kfd_bo->kfd_ipc_obj->key,
- sizeof(kfd_bo->kfd_ipc_obj->key));
+ memcpy(ipc_handle, kfd_bo->kfd_ipc_obj->share_handle,
+ sizeof(kfd_bo->kfd_ipc_obj->share_handle));
return 0;
}
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h
index 52049d2..9ee8627 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_ipc.h
@@ -27,12 +27,11 @@
#include <linux/types.h>
#include "kfd_priv.h"
-#define IPC_KEY_SIZE_BYTES 16
-
struct kfd_ipc_obj {
+ struct hlist_node node;
struct kref ref;
void *data;
- char key[IPC_KEY_SIZE_BYTES];
+ uint32_t share_handle[4];
};
int kfd_ipc_import_handle(struct kfd_dev *dev, struct kfd_process *p,
--
2.7.4
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