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 #include <linux/export.h> 35 36 static void ttm_eu_backoff_reservation_locked(struct list_head *list) 37 { 38 struct ttm_validate_buffer *entry; 39 40 list_for_each_entry(entry, list, head) { 41 struct ttm_buffer_object *bo = entry->bo; 42 if (!entry->reserved) 43 continue; 44 45 entry->reserved = false; 46 if (entry->removed) { 47 ttm_bo_add_to_lru(bo); 48 entry->removed = false; 49 } 50 __ttm_bo_unreserve(bo); 51 } 52 } 53 54 static void ttm_eu_del_from_lru_locked(struct list_head *list) 55 { 56 struct ttm_validate_buffer *entry; 57 58 list_for_each_entry(entry, list, head) { 59 struct ttm_buffer_object *bo = entry->bo; 60 if (!entry->reserved) 61 continue; 62 63 if (!entry->removed) { 64 entry->put_count = ttm_bo_del_from_lru(bo); 65 entry->removed = true; 66 } 67 } 68 } 69 70 static void ttm_eu_list_ref_sub(struct list_head *list) 71 { 72 struct ttm_validate_buffer *entry; 73 74 list_for_each_entry(entry, list, head) { 75 struct ttm_buffer_object *bo = entry->bo; 76 77 if (entry->put_count) { 78 ttm_bo_list_ref_sub(bo, entry->put_count, true); 79 entry->put_count = 0; 80 } 81 } 82 } 83 84 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket, 85 struct list_head *list) 86 { 87 struct ttm_validate_buffer *entry; 88 struct ttm_bo_global *glob; 89 90 if (list_empty(list)) 91 return; 92 93 entry = list_first_entry(list, struct ttm_validate_buffer, head); 94 glob = entry->bo->glob; 95 spin_lock(&glob->lru_lock); 96 ttm_eu_backoff_reservation_locked(list); 97 if (ticket) 98 ww_acquire_fini(ticket); 99 spin_unlock(&glob->lru_lock); 100 } 101 EXPORT_SYMBOL(ttm_eu_backoff_reservation); 102 103 /* 104 * Reserve buffers for validation. 105 * 106 * If a buffer in the list is marked for CPU access, we back off and 107 * wait for that buffer to become free for GPU access. 108 * 109 * If a buffer is reserved for another validation, the validator with 110 * the highest validation sequence backs off and waits for that buffer 111 * to become unreserved. This prevents deadlocks when validating multiple 112 * buffers in different orders. 113 */ 114 115 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket, 116 struct list_head *list) 117 { 118 struct ttm_bo_global *glob; 119 struct ttm_validate_buffer *entry; 120 int ret; 121 122 if (list_empty(list)) 123 return 0; 124 125 list_for_each_entry(entry, list, head) { 126 entry->reserved = false; 127 entry->put_count = 0; 128 entry->removed = false; 129 } 130 131 entry = list_first_entry(list, struct ttm_validate_buffer, head); 132 glob = entry->bo->glob; 133 134 if (ticket) 135 ww_acquire_init(ticket, &reservation_ww_class); 136 retry: 137 list_for_each_entry(entry, list, head) { 138 struct ttm_buffer_object *bo = entry->bo; 139 140 /* already slowpath reserved? */ 141 if (entry->reserved) 142 continue; 143 144 ret = __ttm_bo_reserve(bo, true, (ticket == NULL), true, 145 ticket); 146 147 if (ret == -EDEADLK) { 148 /* uh oh, we lost out, drop every reservation and try 149 * to only reserve this buffer, then start over if 150 * this succeeds. 151 */ 152 BUG_ON(ticket == NULL); 153 spin_lock(&glob->lru_lock); 154 ttm_eu_backoff_reservation_locked(list); 155 spin_unlock(&glob->lru_lock); 156 ttm_eu_list_ref_sub(list); 157 ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock, 158 ticket); 159 if (unlikely(ret != 0)) { 160 if (ret == -EINTR) 161 ret = -ERESTARTSYS; 162 goto err_fini; 163 } 164 165 entry->reserved = true; 166 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { 167 ret = -EBUSY; 168 goto err; 169 } 170 goto retry; 171 } else if (ret) 172 goto err; 173 174 entry->reserved = true; 175 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) { 176 ret = -EBUSY; 177 goto err; 178 } 179 } 180 181 if (ticket) 182 ww_acquire_done(ticket); 183 spin_lock(&glob->lru_lock); 184 ttm_eu_del_from_lru_locked(list); 185 spin_unlock(&glob->lru_lock); 186 ttm_eu_list_ref_sub(list); 187 return 0; 188 189 err: 190 spin_lock(&glob->lru_lock); 191 ttm_eu_backoff_reservation_locked(list); 192 spin_unlock(&glob->lru_lock); 193 ttm_eu_list_ref_sub(list); 194 err_fini: 195 if (ticket) { 196 ww_acquire_done(ticket); 197 ww_acquire_fini(ticket); 198 } 199 return ret; 200 } 201 EXPORT_SYMBOL(ttm_eu_reserve_buffers); 202 203 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket, 204 struct list_head *list, void *sync_obj) 205 { 206 struct ttm_validate_buffer *entry; 207 struct ttm_buffer_object *bo; 208 struct ttm_bo_global *glob; 209 struct ttm_bo_device *bdev; 210 struct ttm_bo_driver *driver; 211 212 if (list_empty(list)) 213 return; 214 215 bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo; 216 bdev = bo->bdev; 217 driver = bdev->driver; 218 glob = bo->glob; 219 220 spin_lock(&glob->lru_lock); 221 spin_lock(&bdev->fence_lock); 222 223 list_for_each_entry(entry, list, head) { 224 bo = entry->bo; 225 entry->old_sync_obj = bo->sync_obj; 226 bo->sync_obj = driver->sync_obj_ref(sync_obj); 227 ttm_bo_add_to_lru(bo); 228 __ttm_bo_unreserve(bo); 229 entry->reserved = false; 230 } 231 spin_unlock(&bdev->fence_lock); 232 spin_unlock(&glob->lru_lock); 233 if (ticket) 234 ww_acquire_fini(ticket); 235 236 list_for_each_entry(entry, list, head) { 237 if (entry->old_sync_obj) 238 driver->sync_obj_unref(&entry->old_sync_obj); 239 } 240 } 241 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects); 242