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 <linux/export.h>
30
31#include <drm/ttm/ttm_execbuf_util.h>
32#include <drm/ttm/ttm_bo.h>
33
34static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
35 struct ttm_validate_buffer *entry)
36{
37 list_for_each_entry_continue_reverse(entry, list, head) {
38 struct ttm_buffer_object *bo = entry->bo;
39
40 dma_resv_unlock(obj: bo->base.resv);
41 }
42}
43
44void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
45 struct list_head *list)
46{
47 struct ttm_validate_buffer *entry;
48
49 if (list_empty(head: list))
50 return;
51
52 list_for_each_entry(entry, list, head) {
53 struct ttm_buffer_object *bo = entry->bo;
54
55 ttm_bo_move_to_lru_tail_unlocked(bo);
56 dma_resv_unlock(obj: bo->base.resv);
57 }
58
59 if (ticket)
60 ww_acquire_fini(ctx: ticket);
61}
62EXPORT_SYMBOL(ttm_eu_backoff_reservation);
63
64/*
65 * Reserve buffers for validation.
66 *
67 * If a buffer in the list is marked for CPU access, we back off and
68 * wait for that buffer to become free for GPU access.
69 *
70 * If a buffer is reserved for another validation, the validator with
71 * the highest validation sequence backs off and waits for that buffer
72 * to become unreserved. This prevents deadlocks when validating multiple
73 * buffers in different orders.
74 */
75
76int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
77 struct list_head *list, bool intr,
78 struct list_head *dups)
79{
80 struct ttm_validate_buffer *entry;
81 int ret;
82
83 if (list_empty(head: list))
84 return 0;
85
86 if (ticket)
87 ww_acquire_init(ctx: ticket, ww_class: &reservation_ww_class);
88
89 list_for_each_entry(entry, list, head) {
90 struct ttm_buffer_object *bo = entry->bo;
91 unsigned int num_fences;
92
93 ret = ttm_bo_reserve(bo, interruptible: intr, no_wait: (ticket == NULL), ticket);
94 if (ret == -EALREADY && dups) {
95 struct ttm_validate_buffer *safe = entry;
96 entry = list_prev_entry(entry, head);
97 list_del(entry: &safe->head);
98 list_add(new: &safe->head, head: dups);
99 continue;
100 }
101
102 num_fences = max(entry->num_shared, 1u);
103 if (!ret) {
104 ret = dma_resv_reserve_fences(obj: bo->base.resv,
105 num_fences);
106 if (!ret)
107 continue;
108 }
109
110 /* uh oh, we lost out, drop every reservation and try
111 * to only reserve this buffer, then start over if
112 * this succeeds.
113 */
114 ttm_eu_backoff_reservation_reverse(list, entry);
115
116 if (ret == -EDEADLK) {
117 ret = ttm_bo_reserve_slowpath(bo, interruptible: intr, ticket);
118 }
119
120 if (!ret)
121 ret = dma_resv_reserve_fences(obj: bo->base.resv,
122 num_fences);
123
124 if (unlikely(ret != 0)) {
125 if (ticket) {
126 ww_acquire_done(ctx: ticket);
127 ww_acquire_fini(ctx: ticket);
128 }
129 return ret;
130 }
131
132 /* move this item to the front of the list,
133 * forces correct iteration of the loop without keeping track
134 */
135 list_del(entry: &entry->head);
136 list_add(new: &entry->head, head: list);
137 }
138
139 return 0;
140}
141EXPORT_SYMBOL(ttm_eu_reserve_buffers);
142
143void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
144 struct list_head *list,
145 struct dma_fence *fence)
146{
147 struct ttm_validate_buffer *entry;
148
149 if (list_empty(head: list))
150 return;
151
152 list_for_each_entry(entry, list, head) {
153 struct ttm_buffer_object *bo = entry->bo;
154
155 dma_resv_add_fence(obj: bo->base.resv, fence, usage: entry->num_shared ?
156 DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
157 ttm_bo_move_to_lru_tail_unlocked(bo);
158 dma_resv_unlock(obj: bo->base.resv);
159 }
160 if (ticket)
161 ww_acquire_fini(ctx: ticket);
162}
163EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
164

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