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 {
  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                 ww_mutex_unlock(&bo->resv->lock);
  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         spin_lock(&glob->lru_lock);
  95         ttm_eu_backoff_reservation_locked(list);
  96         if (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         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_nolru(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                         spin_lock(&glob->lru_lock);
 153                         ttm_eu_backoff_reservation_locked(list);
 154                         spin_unlock(&glob->lru_lock);
 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         spin_lock(&glob->lru_lock);
 183         ttm_eu_del_from_lru_locked(list);
 184         spin_unlock(&glob->lru_lock);
 185         ttm_eu_list_ref_sub(list);
 186         return 0;
 187
 188 err:
 189         spin_lock(&glob->lru_lock);
 190         ttm_eu_backoff_reservation_locked(list);
 191         spin_unlock(&glob->lru_lock);
 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         spin_lock(&glob->lru_lock);
 220         spin_lock(&bdev->fence_lock);
 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                 ww_mutex_unlock(&bo->resv->lock);
 228                 entry->reserved = false;
 229         }
 230         spin_unlock(&bdev->fence_lock);
 231         spin_unlock(&glob->lru_lock);
 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);