diff options
Diffstat (limited to 'drivers/gpu/drm/vmwgfx/ttm_object.c')
| -rw-r--r-- | drivers/gpu/drm/vmwgfx/ttm_object.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/gpu/drm/vmwgfx/ttm_object.c b/drivers/gpu/drm/vmwgfx/ttm_object.c index c5df2d7828e6..36990b80e790 100644 --- a/drivers/gpu/drm/vmwgfx/ttm_object.c +++ b/drivers/gpu/drm/vmwgfx/ttm_object.c @@ -225,6 +225,41 @@ void ttm_base_object_unref(struct ttm_base_object **p_base) kref_put(&base->refcount, ttm_release_base); } +/** + * ttm_base_object_noref_lookup - look up a base object without reference + * @tfile: The struct ttm_object_file the object is registered with. + * @key: The object handle. + * + * This function looks up a ttm base object and returns a pointer to it + * without refcounting the pointer. The returned pointer is only valid + * until ttm_base_object_noref_release() is called, and the object + * pointed to by the returned pointer may be doomed. Any persistent usage + * of the object requires a refcount to be taken using kref_get_unless_zero(). + * Iff this function returns successfully it needs to be paired with + * ttm_base_object_noref_release() and no sleeping- or scheduling functions + * may be called inbetween these function callse. + * + * Return: A pointer to the object if successful or NULL otherwise. + */ +struct ttm_base_object * +ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint32_t key) +{ + struct drm_hash_item *hash; + struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE]; + int ret; + + rcu_read_lock(); + ret = drm_ht_find_item_rcu(ht, key, &hash); + if (ret) { + rcu_read_unlock(); + return NULL; + } + + __release(RCU); + return drm_hash_entry(hash, struct ttm_ref_object, hash)->obj; +} +EXPORT_SYMBOL(ttm_base_object_noref_lookup); + struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile, uint32_t key) { |