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_driver.h> 31 #include <drm/ttm/ttm_placement.h> 32 #include <linux/wait.h> 33 #include <linux/sched.h> 34 #include <linux/module.h> 35 36 static void ttm_eu_backoff_reservation_reverse(struct list_head *list, 37 struct ttm_validate_buffer *entry) 38 { 39 list_for_each_entry_continue_reverse(entry, list, head) { 40 struct ttm_buffer_object *bo = entry->bo; 41 42 dma_resv_unlock(bo->base.resv); 43 } 44 } 45 46 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket, 47 struct list_head *list) 48 { 49 struct ttm_validate_buffer *entry; 50 51 if (list_empty(list)) 52 return; 53 54 list_for_each_entry(entry, list, head) { 55 struct ttm_buffer_object *bo = entry->bo; 56 57 ttm_bo_move_to_lru_tail_unlocked(bo); 58 dma_resv_unlock(bo->base.resv); 59 } 60 61 if (ticket) 62 ww_acquire_fini(ticket); 63 } 64 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 65 66 /* 67 * Reserve buffers for validation. 68 * 69 * If a buffer in the list is marked for CPU access, we back off and 70 * wait for that buffer to become free for GPU access. 71 * 72 * If a buffer is reserved for another validation, the validator with 73 * the highest validation sequence backs off and waits for that buffer 74 * to become unreserved. This prevents deadlocks when validating multiple 75 * buffers in different orders. 76 */ 77 78 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket, 79 struct list_head *list, bool intr, 80 struct list_head *dups) 81 { 82 struct ttm_validate_buffer *entry; 83 int ret; 84 85 if (list_empty(list)) 86 return 0; 87 88 if (ticket) 89 ww_acquire_init(ticket, &reservation_ww_class); 90 91 list_for_each_entry(entry, list, head) { 92 struct ttm_buffer_object *bo = entry->bo; 93 94 ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket); 95 if (ret == -EALREADY && dups) { 96 struct ttm_validate_buffer *safe = entry; 97 entry = list_prev_entry(entry, head); 98 list_del(&safe->head); 99 list_add(&safe->head, dups); 100 continue; 101 } 102 103 if (!ret) { 104 if (!entry->num_shared) 105 continue; 106 107 ret = dma_resv_reserve_shared(bo->base.resv, 108 entry->num_shared); 109 if (!ret) 110 continue; 111 } 112 113 /* uh oh, we lost out, drop every reservation and try 114 * to only reserve this buffer, then start over if 115 * this succeeds. 116 */ 117 ttm_eu_backoff_reservation_reverse(list, entry); 118 119 if (ret == -EDEADLK) { 120 ret = ttm_bo_reserve_slowpath(bo, intr, ticket); 121 } 122 123 if (!ret && entry->num_shared) 124 ret = dma_resv_reserve_shared(bo->base.resv, 125 entry->num_shared); 126 127 if (unlikely(ret != 0)) { 128 if (ticket) { 129 ww_acquire_done(ticket); 130 ww_acquire_fini(ticket); 131 } 132 return ret; 133 } 134 135 /* move this item to the front of the list, 136 * forces correct iteration of the loop without keeping track 137 */ 138 list_del(&entry->head); 139 list_add(&entry->head, list); 140 } 141 142 return 0; 143 } 144 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 145 146 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket, 147 struct list_head *list, 148 struct dma_fence *fence) 149 { 150 struct ttm_validate_buffer *entry; 151 152 if (list_empty(list)) 153 return; 154 155 list_for_each_entry(entry, list, head) { 156 struct ttm_buffer_object *bo = entry->bo; 157 158 if (entry->num_shared) 159 dma_resv_add_shared_fence(bo->base.resv, fence); 160 else 161 dma_resv_add_excl_fence(bo->base.resv, fence); 162 ttm_bo_move_to_lru_tail_unlocked(bo); 163 dma_resv_unlock(bo->base.resv); 164 } 165 if (ticket) 166 ww_acquire_fini(ticket); 167 } 168 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 169