1 /************************************************************************** 2 * 3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA 4 * All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the 8 * "Software"), to deal in the Software without restriction, including 9 * without limitation the rights to use, copy, modify, merge, publish, 10 * distribute, sub license, and/or sell copies of the Software, and to 11 * permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice (including the 15 * next paragraph) shall be included in all copies or substantial portions 16 * of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL 21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, 22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 24 * USE OR OTHER DEALINGS IN THE SOFTWARE. 25 * 26 **************************************************************************/ 27 28 #include <drm/ttm/ttm_execbuf_util.h> 29 #include <drm/ttm/ttm_bo_driver.h> 30 #include <drm/ttm/ttm_placement.h> 31 #include <linux/wait.h> 32 #include <linux/sched.h> 33 #include <linux/module.h> 34 35 static void ttm_eu_backoff_reservation_locked(struct list_head *list) 36 { 37 struct ttm_validate_buffer *entry; 38 39 list_for_each_entry(entry, list, head) { 40 struct ttm_buffer_object *bo = entry->bo; 41 if (!entry->reserved) 42 continue; 43 44 entry->reserved = false; 45 if (entry->removed) { 46 ttm_bo_add_to_lru(bo); 47 entry->removed = false; 48 } 49 __ttm_bo_unreserve(bo); 50 } 51 } 52 53 static void ttm_eu_del_from_lru_locked(struct list_head *list) 54 { 55 struct ttm_validate_buffer *entry; 56 57 list_for_each_entry(entry, list, head) { 58 struct ttm_buffer_object *bo = entry->bo; 59 if (!entry->reserved) 60 continue; 61 62 if (!entry->removed) { 63 entry->put_count = ttm_bo_del_from_lru(bo); 64 entry->removed = true; 65 } 66 } 67 } 68 69 static void ttm_eu_list_ref_sub(struct list_head *list) 70 { 71 struct ttm_validate_buffer *entry; 72 73 list_for_each_entry(entry, list, head) { 74 struct ttm_buffer_object *bo = entry->bo; 75 76 if (entry->put_count) { 77 ttm_bo_list_ref_sub(bo, entry->put_count, true); 78 entry->put_count = 0; 79 } 80 } 81 } 82 83 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket, 84 struct list_head *list) 85 { 86 struct ttm_validate_buffer *entry; 87 struct ttm_bo_global *glob; 88 89 if (list_empty(list)) 90 return; 91 92 entry = list_first_entry(list, struct ttm_validate_buffer, head); 93 glob = entry->bo->glob; 94 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 95 ttm_eu_backoff_reservation_locked(list); 96 if (ticket) 97 ww_acquire_fini(ticket); 98 lockmgr(&glob->lru_lock, LK_RELEASE); 99 } 100 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 101 102 /* 103 * Reserve buffers for validation. 104 * 105 * If a buffer in the list is marked for CPU access, we back off and 106 * wait for that buffer to become free for GPU access. 107 * 108 * If a buffer is reserved for another validation, the validator with 109 * the highest validation sequence backs off and waits for that buffer 110 * to become unreserved. This prevents deadlocks when validating multiple 111 * buffers in different orders. 112 */ 113 114 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket, 115 struct list_head *list) 116 { 117 struct ttm_bo_global *glob; 118 struct ttm_validate_buffer *entry; 119 int ret; 120 121 if (list_empty(list)) 122 return 0; 123 124 list_for_each_entry(entry, list, head) { 125 entry->reserved = false; 126 entry->put_count = 0; 127 entry->removed = false; 128 } 129 130 entry = list_first_entry(list, struct ttm_validate_buffer, head); 131 glob = entry->bo->glob; 132 133 if (ticket) 134 ww_acquire_init(ticket, &reservation_ww_class); 135 retry: 136 list_for_each_entry(entry, list, head) { 137 struct ttm_buffer_object *bo = entry->bo; 138 139 /* already slowpath reserved? */ 140 if (entry->reserved) 141 continue; 142 143 ret = __ttm_bo_reserve(bo, true, (ticket == NULL), true, 144 ticket); 145 146 if (ret == -EDEADLK) { 147 /* uh oh, we lost out, drop every reservation and try 148 * to only reserve this buffer, then start over if 149 * this succeeds. 150 */ 151 BUG_ON(ticket == NULL); 152 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 153 ttm_eu_backoff_reservation_locked(list); 154 lockmgr(&glob->lru_lock, LK_RELEASE); 155 ttm_eu_list_ref_sub(list); 156 ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock, 157 ticket); 158 if (unlikely(ret != 0)) { 159 if (ret == -EINTR) 160 ret = -ERESTARTSYS; 161 goto err_fini; 162 } 163 164 entry->reserved = true; 165 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { 166 ret = -EBUSY; 167 goto err; 168 } 169 goto retry; 170 } else if (ret) 171 goto err; 172 173 entry->reserved = true; 174 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { 175 ret = -EBUSY; 176 goto err; 177 } 178 } 179 180 if (ticket) 181 ww_acquire_done(ticket); 182 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 183 ttm_eu_del_from_lru_locked(list); 184 lockmgr(&glob->lru_lock, LK_RELEASE); 185 ttm_eu_list_ref_sub(list); 186 return 0; 187 188 err: 189 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 190 ttm_eu_backoff_reservation_locked(list); 191 lockmgr(&glob->lru_lock, LK_RELEASE); 192 ttm_eu_list_ref_sub(list); 193 err_fini: 194 if (ticket) { 195 ww_acquire_done(ticket); 196 ww_acquire_fini(ticket); 197 } 198 return ret; 199 } 200 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 201 202 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket, 203 struct list_head *list, void *sync_obj) 204 { 205 struct ttm_validate_buffer *entry; 206 struct ttm_buffer_object *bo; 207 struct ttm_bo_global *glob; 208 struct ttm_bo_device *bdev; 209 struct ttm_bo_driver *driver; 210 211 if (list_empty(list)) 212 return; 213 214 bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo; 215 bdev = bo->bdev; 216 driver = bdev->driver; 217 glob = bo->glob; 218 219 lockmgr(&glob->lru_lock, LK_EXCLUSIVE); 220 lockmgr(&bdev->fence_lock, LK_EXCLUSIVE); 221 222 list_for_each_entry(entry, list, head) { 223 bo = entry->bo; 224 entry->old_sync_obj = bo->sync_obj; 225 bo->sync_obj = driver->sync_obj_ref(sync_obj); 226 ttm_bo_add_to_lru(bo); 227 __ttm_bo_unreserve(bo); 228 entry->reserved = false; 229 } 230 lockmgr(&bdev->fence_lock, LK_RELEASE); 231 lockmgr(&glob->lru_lock, LK_RELEASE); 232 if (ticket) 233 ww_acquire_fini(ticket); 234 235 list_for_each_entry(entry, list, head) { 236 if (entry->old_sync_obj) 237 driver->sync_obj_unref(&entry->old_sync_obj); 238 } 239 } 240 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 241