1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */ 2 /************************************************************************** 3 * 4 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA 5 * All Rights Reserved. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a 8 * copy of this software and associated documentation files (the 9 * "Software"), to deal in the Software without restriction, including 10 * without limitation the rights to use, copy, modify, merge, publish, 11 * distribute, sub license, and/or sell copies of the Software, and to 12 * permit persons to whom the Software is furnished to do so, subject to 13 * the following conditions: 14 * 15 * The above copyright notice and this permission notice (including the 16 * next paragraph) shall be included in all copies or substantial portions 17 * of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 22 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 23 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 24 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 25 * USE OR OTHER DEALINGS IN THE SOFTWARE. 26 * 27 **************************************************************************/ 28 29 #include <drm/ttm/ttm_execbuf_util.h> 30 #include <drm/ttm/ttm_bo.h> 31 32 static void ttm_eu_backoff_reservation_reverse(struct list_head *list, 33 struct ttm_validate_buffer *entry) 34 { 35 list_for_each_entry_continue_reverse(entry, list, head) { 36 struct ttm_buffer_object *bo = entry->bo; 37 38 dma_resv_unlock(bo->base.resv); 39 } 40 } 41 42 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket, 43 struct list_head *list) 44 { 45 struct ttm_validate_buffer *entry; 46 47 if (list_empty(list)) 48 return; 49 50 list_for_each_entry(entry, list, head) { 51 struct ttm_buffer_object *bo = entry->bo; 52 53 ttm_bo_move_to_lru_tail_unlocked(bo); 54 dma_resv_unlock(bo->base.resv); 55 } 56 57 if (ticket) 58 ww_acquire_fini(ticket); 59 } 60 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 61 62 /* 63 * Reserve buffers for validation. 64 * 65 * If a buffer in the list is marked for CPU access, we back off and 66 * wait for that buffer to become free for GPU access. 67 * 68 * If a buffer is reserved for another validation, the validator with 69 * the highest validation sequence backs off and waits for that buffer 70 * to become unreserved. This prevents deadlocks when validating multiple 71 * buffers in different orders. 72 */ 73 74 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket, 75 struct list_head *list, bool intr, 76 struct list_head *dups) 77 { 78 struct ttm_validate_buffer *entry; 79 int ret; 80 81 if (list_empty(list)) 82 return 0; 83 84 if (ticket) 85 ww_acquire_init(ticket, &reservation_ww_class); 86 87 list_for_each_entry(entry, list, head) { 88 struct ttm_buffer_object *bo = entry->bo; 89 unsigned int num_fences; 90 91 ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket); 92 if (ret == -EALREADY && dups) { 93 struct ttm_validate_buffer *safe = entry; 94 entry = list_prev_entry(entry, head); 95 list_del(&safe->head); 96 list_add(&safe->head, dups); 97 continue; 98 } 99 100 num_fences = max(entry->num_shared, 1u); 101 if (!ret) { 102 ret = dma_resv_reserve_fences(bo->base.resv, 103 num_fences); 104 if (!ret) 105 continue; 106 } 107 108 /* uh oh, we lost out, drop every reservation and try 109 * to only reserve this buffer, then start over if 110 * this succeeds. 111 */ 112 ttm_eu_backoff_reservation_reverse(list, entry); 113 114 if (ret == -EDEADLK) { 115 ret = ttm_bo_reserve_slowpath(bo, intr, ticket); 116 } 117 118 if (!ret) 119 ret = dma_resv_reserve_fences(bo->base.resv, 120 num_fences); 121 122 if (unlikely(ret != 0)) { 123 if (ticket) { 124 ww_acquire_done(ticket); 125 ww_acquire_fini(ticket); 126 } 127 return ret; 128 } 129 130 /* move this item to the front of the list, 131 * forces correct iteration of the loop without keeping track 132 */ 133 list_del(&entry->head); 134 list_add(&entry->head, list); 135 } 136 137 return 0; 138 } 139 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 140 141 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket, 142 struct list_head *list, 143 struct dma_fence *fence) 144 { 145 struct ttm_validate_buffer *entry; 146 147 if (list_empty(list)) 148 return; 149 150 list_for_each_entry(entry, list, head) { 151 struct ttm_buffer_object *bo = entry->bo; 152 153 dma_resv_add_fence(bo->base.resv, fence, entry->num_shared ? 154 DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE); 155 ttm_bo_move_to_lru_tail_unlocked(bo); 156 dma_resv_unlock(bo->base.resv); 157 } 158 if (ticket) 159 ww_acquire_fini(ticket); 160 } 161 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 162