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