[PATCH 1/2] drm/amdgpu: Revert "remove the userptr rmn->lock"

[Christian König]

From: Christian König <christian.koe...@amd.com>

This reverts commit c02196834456f2d5fad334088b70e98ce4967c34.

In the meantime we moved get_user_pages() outside of the reservation lock,
so that shouldn't be an issue any more

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
index d7ec9bd..c47f2222 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
@@ -48,7 +48,8 @@ struct amdgpu_mn {
        /* protected by adev->mn_lock */
        struct hlist_node       node;

-       /* objects protected by mm->mmap_sem */
+       /* objects protected by lock */
+       struct mutex            lock;
        struct rb_root          objects;
 };

@@ -72,7 +73,7 @@ static void amdgpu_mn_destroy(struct work_struct *work)
        struct amdgpu_bo *bo, *next_bo;

        mutex_lock(&adev->mn_lock);
-       down_write(&rmn->mm->mmap_sem);
+       mutex_lock(&rmn->lock);
        hash_del(&rmn->node);
        rbtree_postorder_for_each_entry_safe(node, next_node, &rmn->objects,
                                             it.rb) {
@@ -82,7 +83,7 @@ static void amdgpu_mn_destroy(struct work_struct *work)
                }
                kfree(node);
        }
-       up_write(&rmn->mm->mmap_sem);
+       mutex_unlock(&rmn->lock);
        mutex_unlock(&adev->mn_lock);
        mmu_notifier_unregister_no_release(&rmn->mn, rmn->mm);
        kfree(rmn);
@@ -126,6 +127,8 @@ 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;
@@ -160,6 +163,8 @@ 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 = {
@@ -196,6 +201,7 @@ 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);
@@ -242,7 +248,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long 
addr)

        INIT_LIST_HEAD(&bos);

-       down_write(&rmn->mm->mmap_sem);
+       mutex_lock(&rmn->lock);

        while ((it = interval_tree_iter_first(&rmn->objects, addr, end))) {
                kfree(node);
@@ -256,7 +262,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long 
addr)
        if (!node) {
                node = kmalloc(sizeof(struct amdgpu_mn_node), GFP_KERNEL);
                if (!node) {
-                       up_write(&rmn->mm->mmap_sem);
+                       mutex_unlock(&rmn->lock);
                        return -ENOMEM;
                }
        }
@@ -271,7 +277,7 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long 
addr)

        interval_tree_insert(&node->it, &rmn->objects);

-       up_write(&rmn->mm->mmap_sem);
+       mutex_unlock(&rmn->lock);

        return 0;
 }
@@ -297,7 +303,7 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
                return;
        }

-       down_write(&rmn->mm->mmap_sem);
+       mutex_lock(&rmn->lock);

        /* save the next list entry for later */
        head = bo->mn_list.next;
@@ -312,6 +318,6 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
                kfree(node);
        }

-       up_write(&rmn->mm->mmap_sem);
+       mutex_unlock(&rmn->lock);
        mutex_unlock(&adev->mn_lock);
 }
-- 
2.5.0