sys/dev/drm/ttm/ttm_execbuf_util.c

   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/export.h>
  32
  33 static void ttm_eu_backoff_reservation_locked(struct list_head *list)
  34 {
  35         struct ttm_validate_buffer *entry;
  36
  37         list_for_each_entry(entry, list, head) {
  38                 struct ttm_buffer_object *bo = entry->bo;
  39                 if (!entry->reserved)
  40                         continue;
  41
  42                 if (entry->removed) {
  43                         ttm_bo_add_to_lru(bo);
  44                         entry->removed = false;
  45
  46                 }
  47                 entry->reserved = false;
  48                 atomic_set(&bo->reserved, 0);
  49                 wakeup(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 list_head *list)
  84 {
  85         struct ttm_validate_buffer *entry;
  86         struct ttm_bo_global *glob;
  87
  88         if (list_empty(list))
  89                 return;
  90
  91         entry = list_first_entry(list, struct ttm_validate_buffer, head);
  92         glob = entry->bo->glob;
  93         lockmgr(&glob->lru_lock, LK_EXCLUSIVE);
  94         ttm_eu_backoff_reservation_locked(list);
  95         lockmgr(&glob->lru_lock, LK_RELEASE);
  96 }
  97 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  98
  99 /*
 100  * Reserve buffers for validation.
 101  *
 102  * If a buffer in the list is marked for CPU access, we back off and
 103  * wait for that buffer to become free for GPU access.
 104  *
 105  * If a buffer is reserved for another validation, the validator with
 106  * the highest validation sequence backs off and waits for that buffer
 107  * to become unreserved. This prevents deadlocks when validating multiple
 108  * buffers in different orders.
 109  */
 110
 111 int ttm_eu_reserve_buffers(struct list_head *list)
 112 {
 113         struct ttm_bo_global *glob;
 114         struct ttm_validate_buffer *entry;
 115         int ret;
 116         uint32_t val_seq;
 117
 118         if (list_empty(list))
 119                 return 0;
 120
 121         list_for_each_entry(entry, list, head) {
 122                 entry->reserved = false;
 123                 entry->put_count = 0;
 124                 entry->removed = false;
 125         }
 126
 127         entry = list_first_entry(list, struct ttm_validate_buffer, head);
 128         glob = entry->bo->glob;
 129
 130         lockmgr(&glob->lru_lock, LK_EXCLUSIVE);
 131         val_seq = entry->bo->bdev->val_seq++;
 132
 133 retry:
 134         list_for_each_entry(entry, list, head) {
 135                 struct ttm_buffer_object *bo = entry->bo;
 136
 137                 /* already slowpath reserved? */
 138                 if (entry->reserved)
 139                         continue;
 140
 141                 ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq);
 142                 switch (ret) {
 143                 case 0:
 144                         break;
 145                 case -EBUSY:
 146                         ttm_eu_del_from_lru_locked(list);
 147                         lockmgr(&glob->lru_lock, LK_RELEASE);
 148                         ret = ttm_bo_reserve_nolru(bo, true, false,
 149                                                    true, val_seq);
 150                         lockmgr(&glob->lru_lock, LK_EXCLUSIVE);
 151                         if (!ret)
 152                                 break;
 153
 154                         if (unlikely(ret != -EAGAIN))
 155                                 goto err;
 156
 157                         /* fallthrough */
 158                 case -EAGAIN:
 159                         ttm_eu_backoff_reservation_locked(list);
 160
 161                         /*
 162                          * temporarily increase sequence number every retry,
 163                          * to prevent us from seeing our old reservation
 164                          * sequence when someone else reserved the buffer,
 165                          * but hasn't updated the seq_valid/seqno members yet.
 166                          */
 167                         val_seq = entry->bo->bdev->val_seq++;
 168
 169                         lockmgr(&glob->lru_lock, LK_RELEASE);
 170                         ttm_eu_list_ref_sub(list);
 171                         ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq);
 172                         if (unlikely(ret != 0))
 173                                 return ret;
 174                         lockmgr(&glob->lru_lock, LK_EXCLUSIVE);
 175                         entry->reserved = true;
 176                         if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 177                                 ret = -EBUSY;
 178                                 goto err;
 179                         }
 180                         goto retry;
 181                 default:
 182                         goto err;
 183                 }
 184
 185                 entry->reserved = true;
 186                 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 187                         ret = -EBUSY;
 188                         goto err;
 189                 }
 190         }
 191
 192         ttm_eu_del_from_lru_locked(list);
 193         lockmgr(&glob->lru_lock, LK_RELEASE);
 194         ttm_eu_list_ref_sub(list);
 195
 196         return 0;
 197
 198 err:
 199         ttm_eu_backoff_reservation_locked(list);
 200         lockmgr(&glob->lru_lock, LK_RELEASE);
 201         ttm_eu_list_ref_sub(list);
 202         return ret;
 203 }
 204 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 205
 206 void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
 207 {
 208         struct ttm_validate_buffer *entry;
 209         struct ttm_buffer_object *bo;
 210         struct ttm_bo_global *glob;
 211         struct ttm_bo_device *bdev;
 212         struct ttm_bo_driver *driver;
 213
 214         if (list_empty(list))
 215                 return;
 216
 217         bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
 218         bdev = bo->bdev;
 219         driver = bdev->driver;
 220         glob = bo->glob;
 221
 222         lockmgr(&glob->lru_lock, LK_EXCLUSIVE);
 223         lockmgr(&bdev->fence_lock, LK_EXCLUSIVE);
 224
 225         list_for_each_entry(entry, list, head) {
 226                 bo = entry->bo;
 227                 entry->old_sync_obj = bo->sync_obj;
 228                 bo->sync_obj = driver->sync_obj_ref(sync_obj);
 229                 ttm_bo_unreserve_locked(bo);
 230                 entry->reserved = false;
 231         }
 232         lockmgr(&bdev->fence_lock, LK_RELEASE);
 233         lockmgr(&glob->lru_lock, LK_RELEASE);
 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);