drivers/gpu/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/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                                               struct ww_acquire_ctx *ticket)
  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                 ww_mutex_unlock(&bo->resv->lock);
  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, ticket);
  97         ww_acquire_fini(ticket);
  98         spin_unlock(&glob->lru_lock);
  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         ww_acquire_init(ticket, &reservation_ww_class);
 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
 143                 ret = ttm_bo_reserve_nolru(bo, true, false, true, ticket);
 144
 145                 if (ret == -EDEADLK) {
 146                         /* uh oh, we lost out, drop every reservation and try
 147                          * to only reserve this buffer, then start over if
 148                          * this succeeds.
 149                          */
 150                         spin_lock(&glob->lru_lock);
 151                         ttm_eu_backoff_reservation_locked(list, ticket);
 152                         spin_unlock(&glob->lru_lock);
 153                         ttm_eu_list_ref_sub(list);
 154                         ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
 155                                                                ticket);
 156                         if (unlikely(ret != 0)) {
 157                                 if (ret == -EINTR)
 158                                         ret = -ERESTARTSYS;
 159                                 goto err_fini;
 160                         }
 161
 162                         entry->reserved = true;
 163                         if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 164                                 ret = -EBUSY;
 165                                 goto err;
 166                         }
 167                         goto retry;
 168                 } else if (ret)
 169                         goto err;
 170
 171                 entry->reserved = true;
 172                 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 173                         ret = -EBUSY;
 174                         goto err;
 175                 }
 176         }
 177
 178         ww_acquire_done(ticket);
 179         spin_lock(&glob->lru_lock);
 180         ttm_eu_del_from_lru_locked(list);
 181         spin_unlock(&glob->lru_lock);
 182         ttm_eu_list_ref_sub(list);
 183         return 0;
 184
 185 err:
 186         spin_lock(&glob->lru_lock);
 187         ttm_eu_backoff_reservation_locked(list, ticket);
 188         spin_unlock(&glob->lru_lock);
 189         ttm_eu_list_ref_sub(list);
 190 err_fini:
 191         ww_acquire_done(ticket);
 192         ww_acquire_fini(ticket);
 193         return ret;
 194 }
 195 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 196
 197 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
 198                                  struct list_head *list, void *sync_obj)
 199 {
 200         struct ttm_validate_buffer *entry;
 201         struct ttm_buffer_object *bo;
 202         struct ttm_bo_global *glob;
 203         struct ttm_bo_device *bdev;
 204         struct ttm_bo_driver *driver;
 205
 206         if (list_empty(list))
 207                 return;
 208
 209         bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
 210         bdev = bo->bdev;
 211         driver = bdev->driver;
 212         glob = bo->glob;
 213
 214         spin_lock(&glob->lru_lock);
 215         spin_lock(&bdev->fence_lock);
 216
 217         list_for_each_entry(entry, list, head) {
 218                 bo = entry->bo;
 219                 entry->old_sync_obj = bo->sync_obj;
 220                 bo->sync_obj = driver->sync_obj_ref(sync_obj);
 221                 ttm_bo_add_to_lru(bo);
 222                 ww_mutex_unlock(&bo->resv->lock);
 223                 entry->reserved = false;
 224         }
 225         spin_unlock(&bdev->fence_lock);
 226         spin_unlock(&glob->lru_lock);
 227         ww_acquire_fini(ticket);
 228
 229         list_for_each_entry(entry, list, head) {
 230                 if (entry->old_sync_obj)
 231                         driver->sync_obj_unref(&entry->old_sync_obj);
 232         }
 233 }
 234 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);