drivers/gpu/drm/ttm/ttm_execbuf_util.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28
  29 #include <drm/ttm/ttm_execbuf_util.h>
  30 #include <drm/ttm/ttm_bo_driver.h>
  31 #include <drm/ttm/ttm_placement.h>
  32 #include <linux/wait.h>
  33 #include <linux/sched.h>
  34 #include <linux/module.h>
  35
  36 static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
  37                                               struct ttm_validate_buffer *entry)
  38 {
  39         list_for_each_entry_continue_reverse(entry, list, head) {
  40                 struct ttm_buffer_object *bo = entry->bo;
  41
  42                 reservation_object_unlock(bo->resv);
  43         }
  44 }
  45
  46 static void ttm_eu_del_from_lru_locked(struct list_head *list)
  47 {
  48         struct ttm_validate_buffer *entry;
  49
  50         list_for_each_entry(entry, list, head) {
  51                 struct ttm_buffer_object *bo = entry->bo;
  52                 ttm_bo_del_from_lru(bo);
  53         }
  54 }
  55
  56 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
  57                                 struct list_head *list)
  58 {
  59         struct ttm_validate_buffer *entry;
  60         struct ttm_bo_global *glob;
  61
  62         if (list_empty(list))
  63                 return;
  64
  65         entry = list_first_entry(list, struct ttm_validate_buffer, head);
  66         glob = entry->bo->bdev->glob;
  67
  68         spin_lock(&glob->lru_lock);
  69         list_for_each_entry(entry, list, head) {
  70                 struct ttm_buffer_object *bo = entry->bo;
  71
  72                 ttm_bo_add_to_lru(bo);
  73                 reservation_object_unlock(bo->resv);
  74         }
  75         spin_unlock(&glob->lru_lock);
  76
  77         if (ticket)
  78                 ww_acquire_fini(ticket);
  79 }
  80 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  81
  82 /*
  83  * Reserve buffers for validation.
  84  *
  85  * If a buffer in the list is marked for CPU access, we back off and
  86  * wait for that buffer to become free for GPU access.
  87  *
  88  * If a buffer is reserved for another validation, the validator with
  89  * the highest validation sequence backs off and waits for that buffer
  90  * to become unreserved. This prevents deadlocks when validating multiple
  91  * buffers in different orders.
  92  */
  93
  94 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  95                            struct list_head *list, bool intr,
  96                            struct list_head *dups)
  97 {
  98         struct ttm_bo_global *glob;
  99         struct ttm_validate_buffer *entry;
 100         int ret;
 101
 102         if (list_empty(list))
 103                 return 0;
 104
 105         entry = list_first_entry(list, struct ttm_validate_buffer, head);
 106         glob = entry->bo->bdev->glob;
 107
 108         if (ticket)
 109                 ww_acquire_init(ticket, &reservation_ww_class);
 110
 111         list_for_each_entry(entry, list, head) {
 112                 struct ttm_buffer_object *bo = entry->bo;
 113
 114                 ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
 115                 if (!ret && unlikely(atomic_read(&bo->cpu_writers) > 0)) {
 116                         reservation_object_unlock(bo->resv);
 117
 118                         ret = -EBUSY;
 119
 120                 } else if (ret == -EALREADY && dups) {
 121                         struct ttm_validate_buffer *safe = entry;
 122                         entry = list_prev_entry(entry, head);
 123                         list_del(&safe->head);
 124                         list_add(&safe->head, dups);
 125                         continue;
 126                 }
 127
 128                 if (!ret) {
 129                         if (!entry->shared)
 130                                 continue;
 131
 132                         ret = reservation_object_reserve_shared(bo->resv);
 133                         if (!ret)
 134                                 continue;
 135                 }
 136
 137                 /* uh oh, we lost out, drop every reservation and try
 138                  * to only reserve this buffer, then start over if
 139                  * this succeeds.
 140                  */
 141                 ttm_eu_backoff_reservation_reverse(list, entry);
 142
 143                 if (ret == -EDEADLK) {
 144                         if (intr) {
 145                                 ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
 146                                                                        ticket);
 147                         } else {
 148                                 ww_mutex_lock_slow(&bo->resv->lock, ticket);
 149                                 ret = 0;
 150                         }
 151                 }
 152
 153                 if (!ret && entry->shared)
 154                         ret = reservation_object_reserve_shared(bo->resv);
 155
 156                 if (unlikely(ret != 0)) {
 157                         if (ret == -EINTR)
 158                                 ret = -ERESTARTSYS;
 159                         if (ticket) {
 160                                 ww_acquire_done(ticket);
 161                                 ww_acquire_fini(ticket);
 162                         }
 163                         return ret;
 164                 }
 165
 166                 /* move this item to the front of the list,
 167                  * forces correct iteration of the loop without keeping track
 168                  */
 169                 list_del(&entry->head);
 170                 list_add(&entry->head, list);
 171         }
 172
 173         if (ticket)
 174                 ww_acquire_done(ticket);
 175         spin_lock(&glob->lru_lock);
 176         ttm_eu_del_from_lru_locked(list);
 177         spin_unlock(&glob->lru_lock);
 178         return 0;
 179 }
 180 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 181
 182 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
 183                                  struct list_head *list,
 184                                  struct dma_fence *fence)
 185 {
 186         struct ttm_validate_buffer *entry;
 187         struct ttm_buffer_object *bo;
 188         struct ttm_bo_global *glob;
 189         struct ttm_bo_device *bdev;
 190         struct ttm_bo_driver *driver;
 191
 192         if (list_empty(list))
 193                 return;
 194
 195         bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
 196         bdev = bo->bdev;
 197         driver = bdev->driver;
 198         glob = bo->bdev->glob;
 199
 200         spin_lock(&glob->lru_lock);
 201
 202         list_for_each_entry(entry, list, head) {
 203                 bo = entry->bo;
 204                 if (entry->shared)
 205                         reservation_object_add_shared_fence(bo->resv, fence);
 206                 else
 207                         reservation_object_add_excl_fence(bo->resv, fence);
 208                 ttm_bo_add_to_lru(bo);
 209                 reservation_object_unlock(bo->resv);
 210         }
 211         spin_unlock(&glob->lru_lock);
 212         if (ticket)
 213                 ww_acquire_fini(ticket);
 214 }
 215 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);