From c41d271d751ea023f67f1ea755e144b49079b6d5 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Christian=20K=C3=B6nig?= Date: Tue, 9 Feb 2016 16:13:37 +0100 Subject: [PATCH] drm/amdgpu: remove the userptr rmn->lock MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 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 Reviewed-by: Felix Kuehling --- 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 d4e2780c0796..61f0e3c3172a 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); } -- 2.20.1