redonkable/alistair23-linux
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drm/amdgpu: remove the userptr rmn->lock

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Avoid a lock inversion problem by just using the mmap_sem to
protect the entries of the intervall tree.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
This commit is contained in:
Christian König 2016-02-09 16:13:37 +01:00 committed by Alex Deucher
parent e7813d0cd8
commit c41d271d75
1 changed files with 12 additions and 20 deletions
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32
drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
View file

@ -48,8 +48,7 @@ struct amdgpu_mn {
/* protected by adev->mn_lock */
struct hlist_node node;
/* objects protected by lock */
struct mutex lock;
/* objects protected by mm->mmap_sem */
struct rb_root objects;
};
@ -72,8 +71,8 @@ static void amdgpu_mn_destroy(struct work_struct *work)
struct amdgpu_mn_node *node, *next_node;
struct amdgpu_bo *bo, *next_bo;
down_write(&rmn->mm->mmap_sem);
mutex_lock(&adev->mn_lock);
mutex_lock(&rmn->lock);
hash_del(&rmn->node);
rbtree_postorder_for_each_entry_safe(node, next_node, &rmn->objects,
it.rb) {
@ -85,8 +84,8 @@ static void amdgpu_mn_destroy(struct work_struct *work)
}
kfree(node);
}
mutex_unlock(&rmn->lock);
mutex_unlock(&adev->mn_lock);
up_write(&rmn->mm->mmap_sem);
mmu_notifier_unregister(&rmn->mn, rmn->mm);
kfree(rmn);
}
@ -129,8 +128,6 @@ static void amdgpu_mn_invalidate_range_start(struct mmu_notifier *mn,
/* notification is exclusive, but interval is inclusive */
end -= 1;
mutex_lock(&rmn->lock);
it = interval_tree_iter_first(&rmn->objects, start, end);
while (it) {
struct amdgpu_mn_node *node;
@ -165,8 +162,6 @@ static void amdgpu_mn_invalidate_range_start(struct mmu_notifier *mn,
amdgpu_bo_unreserve(bo);
}
}
mutex_unlock(&rmn->lock);
}
static const struct mmu_notifier_ops amdgpu_mn_ops = {
@ -203,7 +198,6 @@ static struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev)
rmn->adev = adev;
rmn->mm = mm;
rmn->mn.ops = &amdgpu_mn_ops;
mutex_init(&rmn->lock);
rmn->objects = RB_ROOT;
r = __mmu_notifier_register(&rmn->mn, mm);
@ -250,7 +244,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
INIT_LIST_HEAD(&bos);
mutex_lock(&rmn->lock);
down_write(&rmn->mm->mmap_sem);
while ((it = interval_tree_iter_first(&rmn->objects, addr, end))) {
kfree(node);
@ -264,7 +258,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
if (!node) {
node = kmalloc(sizeof(struct amdgpu_mn_node), GFP_KERNEL);
if (!node) {
mutex_unlock(&rmn->lock);
up_write(&rmn->mm->mmap_sem);
return -ENOMEM;
}
}
@ -279,7 +273,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
interval_tree_insert(&node->it, &rmn->objects);
mutex_unlock(&rmn->lock);
up_write(&rmn->mm->mmap_sem);
return 0;
}
@ -294,17 +288,15 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
void amdgpu_mn_unregister(struct amdgpu_bo *bo)
{
struct amdgpu_device *adev = bo->adev;
struct amdgpu_mn *rmn;
struct amdgpu_mn *rmn = bo->mn;
struct list_head *head;
mutex_lock(&adev->mn_lock);
rmn = bo->mn;
if (rmn == NULL) {
mutex_unlock(&adev->mn_lock);
if (rmn == NULL)
return;
}
mutex_lock(&rmn->lock);
down_write(&rmn->mm->mmap_sem);
mutex_lock(&adev->mn_lock);
/* save the next list entry for later */
head = bo->mn_list.next;
@ -318,6 +310,6 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
kfree(node);
}
mutex_unlock(&rmn->lock);
mutex_unlock(&adev->mn_lock);
up_write(&rmn->mm->mmap_sem);
}