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Commit c41d271d authored by Christian König's avatar Christian König Committed by Alex Deucher
Browse files

drm/amdgpu: remove the userptr rmn->lock 



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

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
parent e7813d0c

drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c

+12 −20
Original line number Diff line number Diff line
@@ -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);

}