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 <linux/export.h> 30 31 #include <drm/ttm/ttm_execbuf_util.h> 32 #include <drm/ttm/ttm_bo.h> 33 34 static void ttm_eu_backoff_reservation_reverse(struct list_head *list, 35 struct ttm_validate_buffer *entry) 36 { 37 list_for_each_entry_continue_reverse(entry, list, head) { 38 struct ttm_buffer_object *bo = entry->bo; 39 40 dma_resv_unlock(bo->base.resv); 41 } 42 } 43 44 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket, 45 struct list_head *list) 46 { 47 struct ttm_validate_buffer *entry; 48 49 if (list_empty(list)) 50 return; 51 52 list_for_each_entry(entry, list, head) { 53 struct ttm_buffer_object *bo = entry->bo; 54 55 ttm_bo_move_to_lru_tail_unlocked(bo); 56 dma_resv_unlock(bo->base.resv); 57 } 58 59 if (ticket) 60 ww_acquire_fini(ticket); 61 } 62 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 63 64 /* 65 * Reserve buffers for validation. 66 * 67 * If a buffer in the list is marked for CPU access, we back off and 68 * wait for that buffer to become free for GPU access. 69 * 70 * If a buffer is reserved for another validation, the validator with 71 * the highest validation sequence backs off and waits for that buffer 72 * to become unreserved. This prevents deadlocks when validating multiple 73 * buffers in different orders. 74 */ 75 76 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket, 77 struct list_head *list, bool intr, 78 struct list_head *dups) 79 { 80 struct ttm_validate_buffer *entry; 81 int ret; 82 83 if (list_empty(list)) 84 return 0; 85 86 if (ticket) 87 ww_acquire_init(ticket, &reservation_ww_class); 88 89 list_for_each_entry(entry, list, head) { 90 struct ttm_buffer_object *bo = entry->bo; 91 unsigned int num_fences; 92 93 ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket); 94 if (ret == -EALREADY && dups) { 95 struct ttm_validate_buffer *safe = entry; 96 entry = list_prev_entry(entry, head); 97 list_del(&safe->head); 98 list_add(&safe->head, dups); 99 continue; 100 } 101 102 num_fences = max(entry->num_shared, 1u); 103 if (!ret) { 104 ret = dma_resv_reserve_fences(bo->base.resv, 105 num_fences); 106 if (!ret) 107 continue; 108 } 109 110 /* uh oh, we lost out, drop every reservation and try 111 * to only reserve this buffer, then start over if 112 * this succeeds. 113 */ 114 ttm_eu_backoff_reservation_reverse(list, entry); 115 116 if (ret == -EDEADLK) { 117 ret = ttm_bo_reserve_slowpath(bo, intr, ticket); 118 } 119 120 if (!ret) 121 ret = dma_resv_reserve_fences(bo->base.resv, 122 num_fences); 123 124 if (unlikely(ret != 0)) { 125 if (ticket) { 126 ww_acquire_done(ticket); 127 ww_acquire_fini(ticket); 128 } 129 return ret; 130 } 131 132 /* move this item to the front of the list, 133 * forces correct iteration of the loop without keeping track 134 */ 135 list_del(&entry->head); 136 list_add(&entry->head, list); 137 } 138 139 return 0; 140 } 141 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 142 143 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket, 144 struct list_head *list, 145 struct dma_fence *fence) 146 { 147 struct ttm_validate_buffer *entry; 148 149 if (list_empty(list)) 150 return; 151 152 list_for_each_entry(entry, list, head) { 153 struct ttm_buffer_object *bo = entry->bo; 154 155 dma_resv_add_fence(bo->base.resv, fence, entry->num_shared ? 156 DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE); 157 ttm_bo_move_to_lru_tail_unlocked(bo); 158 dma_resv_unlock(bo->base.resv); 159 } 160 if (ticket) 161 ww_acquire_fini(ticket); 162 } 163 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 164