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.h>
31
32static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
33 struct ttm_validate_buffer *entry)
34{
35 list_for_each_entry_continue_reverse(entry, list, head) {
36 struct ttm_buffer_object *bo = entry->bo;
37
38 dma_resv_unlock(obj: bo->base.resv);
39 }
40}
41
42void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
43 struct list_head *list)
44{
45 struct ttm_validate_buffer *entry;
46
47 if (list_empty(head: list))
48 return;
49
50 list_for_each_entry(entry, list, head) {
51 struct ttm_buffer_object *bo = entry->bo;
52
53 ttm_bo_move_to_lru_tail_unlocked(bo);
54 dma_resv_unlock(obj: bo->base.resv);
55 }
56
57 if (ticket)
58 ww_acquire_fini(ctx: ticket);
59}
60EXPORT_SYMBOL(ttm_eu_backoff_reservation);
61
62/*
63 * Reserve buffers for validation.
64 *
65 * If a buffer in the list is marked for CPU access, we back off and
66 * wait for that buffer to become free for GPU access.
67 *
68 * If a buffer is reserved for another validation, the validator with
69 * the highest validation sequence backs off and waits for that buffer
70 * to become unreserved. This prevents deadlocks when validating multiple
71 * buffers in different orders.
72 */
73
74int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
75 struct list_head *list, bool intr,
76 struct list_head *dups)
77{
78 struct ttm_validate_buffer *entry;
79 int ret;
80
81 if (list_empty(head: list))
82 return 0;
83
84 if (ticket)
85 ww_acquire_init(ctx: ticket, ww_class: &reservation_ww_class);
86
87 list_for_each_entry(entry, list, head) {
88 struct ttm_buffer_object *bo = entry->bo;
89 unsigned int num_fences;
90
91 ret = ttm_bo_reserve(bo, interruptible: intr, no_wait: (ticket == NULL), ticket);
92 if (ret == -EALREADY && dups) {
93 struct ttm_validate_buffer *safe = entry;
94 entry = list_prev_entry(entry, head);
95 list_del(entry: &safe->head);
96 list_add(new: &safe->head, head: dups);
97 continue;
98 }
99
100 num_fences = max(entry->num_shared, 1u);
101 if (!ret) {
102 ret = dma_resv_reserve_fences(obj: bo->base.resv,
103 num_fences);
104 if (!ret)
105 continue;
106 }
107
108 /* uh oh, we lost out, drop every reservation and try
109 * to only reserve this buffer, then start over if
110 * this succeeds.
111 */
112 ttm_eu_backoff_reservation_reverse(list, entry);
113
114 if (ret == -EDEADLK) {
115 ret = ttm_bo_reserve_slowpath(bo, interruptible: intr, ticket);
116 }
117
118 if (!ret)
119 ret = dma_resv_reserve_fences(obj: bo->base.resv,
120 num_fences);
121
122 if (unlikely(ret != 0)) {
123 if (ticket) {
124 ww_acquire_done(ctx: ticket);
125 ww_acquire_fini(ctx: ticket);
126 }
127 return ret;
128 }
129
130 /* move this item to the front of the list,
131 * forces correct iteration of the loop without keeping track
132 */
133 list_del(entry: &entry->head);
134 list_add(new: &entry->head, head: list);
135 }
136
137 return 0;
138}
139EXPORT_SYMBOL(ttm_eu_reserve_buffers);
140
141void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
142 struct list_head *list,
143 struct dma_fence *fence)
144{
145 struct ttm_validate_buffer *entry;
146
147 if (list_empty(head: list))
148 return;
149
150 list_for_each_entry(entry, list, head) {
151 struct ttm_buffer_object *bo = entry->bo;
152
153 dma_resv_add_fence(obj: bo->base.resv, fence, usage: entry->num_shared ?
154 DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
155 ttm_bo_move_to_lru_tail_unlocked(bo);
156 dma_resv_unlock(obj: bo->base.resv);
157 }
158 if (ticket)
159 ww_acquire_fini(ctx: ticket);
160}
161EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
162

source code of linux/drivers/gpu/drm/ttm/ttm_execbuf_util.c