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From 7dd3151852b73a79dc9ed8e3d4bb3a3c16ed927e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Tue, 9 Feb 2016 16:13:37 +0100
Subject: [PATCH 0301/1110] drm/amdgpu: remove the userptr rmn->lock
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 32 ++++++++++++--------------------
1 file changed, 12 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
index d4e2780..61f0e3c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
@@ -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);
}
--
2.7.4
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