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                 dma_resv_unlock(bo->base.resv);
  43         }
  44 }
  45
  46 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
  47                                 struct list_head *list)
  48 {
  49         struct ttm_validate_buffer *entry;
  50
  51         if (list_empty(list))
  52                 return;
  53
  54         list_for_each_entry(entry, list, head) {
  55                 struct ttm_buffer_object *bo = entry->bo;
  56
  57                 ttm_bo_move_to_lru_tail_unlocked(bo);
  58                 dma_resv_unlock(bo->base.resv);
  59         }
  60
  61         if (ticket)
  62                 ww_acquire_fini(ticket);
  63 }
  64 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
  65
  66 /*
  67  * Reserve buffers for validation.
  68  *
  69  * If a buffer in the list is marked for CPU access, we back off and
  70  * wait for that buffer to become free for GPU access.
  71  *
  72  * If a buffer is reserved for another validation, the validator with
  73  * the highest validation sequence backs off and waits for that buffer
  74  * to become unreserved. This prevents deadlocks when validating multiple
  75  * buffers in different orders.
  76  */
  77
  78 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
  79                            struct list_head *list, bool intr,
  80                            struct list_head *dups)
  81 {
  82         struct ttm_validate_buffer *entry;
  83         int ret;
  84
  85         if (list_empty(list))
  86                 return 0;
  87
  88         if (ticket)
  89                 ww_acquire_init(ticket, &reservation_ww_class);
  90
  91         list_for_each_entry(entry, list, head) {
  92                 struct ttm_buffer_object *bo = entry->bo;
  93
  94                 ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
  95                 if (ret == -EALREADY && dups) {
  96                         struct ttm_validate_buffer *safe = entry;
  97                         entry = list_prev_entry(entry, head);
  98                         list_del(&safe->head);
  99                         list_add(&safe->head, dups);
 100                         continue;
 101                 }
 102
 103                 if (!ret) {
 104                         if (!entry->num_shared)
 105                                 continue;
 106
 107                         ret = dma_resv_reserve_shared(bo->base.resv,
 108                                                                 entry->num_shared);
 109                         if (!ret)
 110                                 continue;
 111                 }
 112
 113                 /* uh oh, we lost out, drop every reservation and try
 114                  * to only reserve this buffer, then start over if
 115                  * this succeeds.
 116                  */
 117                 ttm_eu_backoff_reservation_reverse(list, entry);
 118
 119                 if (ret == -EDEADLK) {
 120                         ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
 121                 }
 122
 123                 if (!ret && entry->num_shared)
 124                         ret = dma_resv_reserve_shared(bo->base.resv,
 125                                                                 entry->num_shared);
 126
 127                 if (unlikely(ret != 0)) {
 128                         if (ticket) {
 129                                 ww_acquire_done(ticket);
 130                                 ww_acquire_fini(ticket);
 131                         }
 132                         return ret;
 133                 }
 134
 135                 /* move this item to the front of the list,
 136                  * forces correct iteration of the loop without keeping track
 137                  */
 138                 list_del(&entry->head);
 139                 list_add(&entry->head, list);
 140         }
 141
 142         return 0;
 143 }
 144 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
 145
 146 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
 147                                  struct list_head *list,
 148                                  struct dma_fence *fence)
 149 {
 150         struct ttm_validate_buffer *entry;
 151
 152         if (list_empty(list))
 153                 return;
 154
 155         list_for_each_entry(entry, list, head) {
 156                 struct ttm_buffer_object *bo = entry->bo;
 157
 158                 if (entry->num_shared)
 159                         dma_resv_add_shared_fence(bo->base.resv, fence);
 160                 else
 161                         dma_resv_add_excl_fence(bo->base.resv, fence);
 162                 ttm_bo_move_to_lru_tail_unlocked(bo);
 163                 dma_resv_unlock(bo->base.resv);
 164         }
 165         if (ticket)
 166                 ww_acquire_fini(ticket);
 167 }
 168 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);