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 reservation_object_unlock(bo->resv); 43 } 44 } 45 46 static void ttm_eu_del_from_lru_locked(struct list_head *list) 47 { 48 struct ttm_validate_buffer *entry; 49 50 list_for_each_entry(entry, list, head) { 51 struct ttm_buffer_object *bo = entry->bo; 52 ttm_bo_del_from_lru(bo); 53 } 54 } 55 56 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket, 57 struct list_head *list) 58 { 59 struct ttm_validate_buffer *entry; 60 struct ttm_bo_global *glob; 61 62 if (list_empty(list)) 63 return; 64 65 entry = list_first_entry(list, struct ttm_validate_buffer, head); 66 glob = entry->bo->bdev->glob; 67 68 spin_lock(&glob->lru_lock); 69 list_for_each_entry(entry, list, head) { 70 struct ttm_buffer_object *bo = entry->bo; 71 72 ttm_bo_add_to_lru(bo); 73 reservation_object_unlock(bo->resv); 74 } 75 spin_unlock(&glob->lru_lock); 76 77 if (ticket) 78 ww_acquire_fini(ticket); 79 } 80 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 81 82 /* 83 * Reserve buffers for validation. 84 * 85 * If a buffer in the list is marked for CPU access, we back off and 86 * wait for that buffer to become free for GPU access. 87 * 88 * If a buffer is reserved for another validation, the validator with 89 * the highest validation sequence backs off and waits for that buffer 90 * to become unreserved. This prevents deadlocks when validating multiple 91 * buffers in different orders. 92 */ 93 94 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket, 95 struct list_head *list, bool intr, 96 struct list_head *dups) 97 { 98 struct ttm_bo_global *glob; 99 struct ttm_validate_buffer *entry; 100 int ret; 101 102 if (list_empty(list)) 103 return 0; 104 105 entry = list_first_entry(list, struct ttm_validate_buffer, head); 106 glob = entry->bo->bdev->glob; 107 108 if (ticket) 109 ww_acquire_init(ticket, &reservation_ww_class); 110 111 list_for_each_entry(entry, list, head) { 112 struct ttm_buffer_object *bo = entry->bo; 113 114 ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), ticket); 115 if (!ret && unlikely(atomic_read(&bo->cpu_writers) > 0)) { 116 reservation_object_unlock(bo->resv); 117 118 ret = -EBUSY; 119 120 } else if (ret == -EALREADY && dups) { 121 struct ttm_validate_buffer *safe = entry; 122 entry = list_prev_entry(entry, head); 123 list_del(&safe->head); 124 list_add(&safe->head, dups); 125 continue; 126 } 127 128 if (!ret) { 129 if (!entry->shared) 130 continue; 131 132 ret = reservation_object_reserve_shared(bo->resv); 133 if (!ret) 134 continue; 135 } 136 137 /* uh oh, we lost out, drop every reservation and try 138 * to only reserve this buffer, then start over if 139 * this succeeds. 140 */ 141 ttm_eu_backoff_reservation_reverse(list, entry); 142 143 if (ret == -EDEADLK) { 144 if (intr) { 145 ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock, 146 ticket); 147 } else { 148 ww_mutex_lock_slow(&bo->resv->lock, ticket); 149 ret = 0; 150 } 151 } 152 153 if (!ret && entry->shared) 154 ret = reservation_object_reserve_shared(bo->resv); 155 156 if (unlikely(ret != 0)) { 157 if (ret == -EINTR) 158 ret = -ERESTARTSYS; 159 if (ticket) { 160 ww_acquire_done(ticket); 161 ww_acquire_fini(ticket); 162 } 163 return ret; 164 } 165 166 /* move this item to the front of the list, 167 * forces correct iteration of the loop without keeping track 168 */ 169 list_del(&entry->head); 170 list_add(&entry->head, list); 171 } 172 173 if (ticket) 174 ww_acquire_done(ticket); 175 spin_lock(&glob->lru_lock); 176 ttm_eu_del_from_lru_locked(list); 177 spin_unlock(&glob->lru_lock); 178 return 0; 179 } 180 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 181 182 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket, 183 struct list_head *list, 184 struct dma_fence *fence) 185 { 186 struct ttm_validate_buffer *entry; 187 struct ttm_buffer_object *bo; 188 struct ttm_bo_global *glob; 189 struct ttm_bo_device *bdev; 190 struct ttm_bo_driver *driver; 191 192 if (list_empty(list)) 193 return; 194 195 bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo; 196 bdev = bo->bdev; 197 driver = bdev->driver; 198 glob = bo->bdev->glob; 199 200 spin_lock(&glob->lru_lock); 201 202 list_for_each_entry(entry, list, head) { 203 bo = entry->bo; 204 if (entry->shared) 205 reservation_object_add_shared_fence(bo->resv, fence); 206 else 207 reservation_object_add_excl_fence(bo->resv, fence); 208 ttm_bo_add_to_lru(bo); 209 reservation_object_unlock(bo->resv); 210 } 211 spin_unlock(&glob->lru_lock); 212 if (ticket) 213 ww_acquire_fini(ticket); 214 } 215 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 216