drm/ttm: Export ttm_bo_get_unless_zero()

Export ttm_bo_get_unless_zero() to be used when looking up buffer
objects that are removed from the lookup structure in the destructor.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
This commit is contained in:
Thomas Hellstrom 2018-09-26 15:57:46 +02:00
parent e14c02e6b6
commit 24dc64c1ba
2 changed files with 19 additions and 2 deletions

View File

@ -409,8 +409,7 @@ static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,
node = drm_vma_offset_lookup_locked(&bdev->vma_manager, offset, pages);
if (likely(node)) {
bo = container_of(node, struct ttm_buffer_object, vma_node);
if (!kref_get_unless_zero(&bo->kref))
bo = NULL;
bo = ttm_bo_get_unless_zero(bo);
}
drm_vma_offset_unlock_lookup(&bdev->vma_manager);

View File

@ -312,6 +312,24 @@ ttm_bo_reference(struct ttm_buffer_object *bo)
return bo;
}
/**
* ttm_bo_get_unless_zero - reference a struct ttm_buffer_object unless
* its refcount has already reached zero.
* @bo: The buffer object.
*
* Used to reference a TTM buffer object in lookups where the object is removed
* from the lookup structure during the destructor and for RCU lookups.
*
* Returns: @bo if the referencing was successful, NULL otherwise.
*/
static inline __must_check struct ttm_buffer_object *
ttm_bo_get_unless_zero(struct ttm_buffer_object *bo)
{
if (!kref_get_unless_zero(&bo->kref))
return NULL;
return bo;
}
/**
* ttm_bo_wait - wait for buffer idle.
*