1 /* 2 * Copyright 2018 Advanced Micro Devices, Inc. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in 12 * all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 20 * OTHER DEALINGS IN THE SOFTWARE. 21 * 22 * 23 */ 24 25 #ifndef _TTM_BO_INTERNAL_H_ 26 #define _TTM_BO_INTERNAL_H_ 27 28 #include <drm/ttm/ttm_bo.h> 29 30 /** 31 * ttm_bo_get - reference a struct ttm_buffer_object 32 * 33 * @bo: The buffer object. 34 */ 35 static inline void ttm_bo_get(struct ttm_buffer_object *bo) 36 { 37 kref_get(&bo->kref); 38 } 39 40 /** 41 * ttm_bo_get_unless_zero - reference a struct ttm_buffer_object unless 42 * its refcount has already reached zero. 43 * @bo: The buffer object. 44 * 45 * Used to reference a TTM buffer object in lookups where the object is removed 46 * from the lookup structure during the destructor and for RCU lookups. 47 * 48 * Returns: @bo if the referencing was successful, NULL otherwise. 49 */ 50 static inline __must_check struct ttm_buffer_object * 51 ttm_bo_get_unless_zero(struct ttm_buffer_object *bo) 52 { 53 if (!kref_get_unless_zero(&bo->kref)) 54 return NULL; 55 return bo; 56 } 57 58 #endif 59