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authorThomas Hellstrom <thellstrom@vmware.com>2012-11-21 14:53:21 +0000
committerDave Airlie <airlied@redhat.com>2012-11-28 18:37:59 +1000
commit82fe50bcc87e508e85250c87b745296a36a07897 (patch)
tree6fd205d9d0a92391e9bf5cf31a442a54992fe0b5 /drivers/gpu/drm/ttm/ttm_bo_vm.c
parent5293908afa04b651cc8a7e85ba0938b71f97c2f8 (diff)
drm/ttm: Optimize vm locking using kref_get_unless_zero v3
Removes the need for a write lock each time we call ttm_bo_unref(). v2: Remove an unused variable. v3: Really remove the unused variable. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/ttm/ttm_bo_vm.c')
-rw-r--r--drivers/gpu/drm/ttm/ttm_bo_vm.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 3ba72dbdc4bd..74705f329d99 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -259,8 +259,8 @@ int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
read_lock(&bdev->vm_lock);
bo = ttm_bo_vm_lookup_rb(bdev, vma->vm_pgoff,
(vma->vm_end - vma->vm_start) >> PAGE_SHIFT);
- if (likely(bo != NULL))
- ttm_bo_reference(bo);
+ if (likely(bo != NULL) && !kref_get_unless_zero(&bo->kref))
+ bo = NULL;
read_unlock(&bdev->vm_lock);
if (unlikely(bo == NULL)) {