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
ttm_eu_backoff_reservation_reverse(struct list_head * list,struct ttm_validate_buffer * entry)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
ttm_eu_backoff_reservation(struct ww_acquire_ctx * ticket,struct list_head * list)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
ttm_eu_reserve_buffers(struct ww_acquire_ctx * ticket,struct list_head * list,bool intr,struct list_head * dups)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 unsigned int num_fences;
94
95 ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
96 if (ret == -EALREADY && dups) {
97 struct ttm_validate_buffer *safe = entry;
98 entry = list_prev_entry(entry, head);
99 list_del(&safe->head);
100 list_add(&safe->head, dups);
101 continue;
102 }
103
104 num_fences = max(entry->num_shared, 1u);
105 if (!ret) {
106 ret = dma_resv_reserve_fences(bo->base.resv,
107 num_fences);
108 if (!ret)
109 continue;
110 }
111
112 /* uh oh, we lost out, drop every reservation and try
113 * to only reserve this buffer, then start over if
114 * this succeeds.
115 */
116 ttm_eu_backoff_reservation_reverse(list, entry);
117
118 if (ret == -EDEADLK) {
119 ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
120 }
121
122 if (!ret)
123 ret = dma_resv_reserve_fences(bo->base.resv,
124 num_fences);
125
126 if (unlikely(ret != 0)) {
127 if (ticket) {
128 ww_acquire_done(ticket);
129 ww_acquire_fini(ticket);
130 }
131 return ret;
132 }
133
134 /* move this item to the front of the list,
135 * forces correct iteration of the loop without keeping track
136 */
137 list_del(&entry->head);
138 list_add(&entry->head, list);
139 }
140
141 return 0;
142 }
143 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
144
ttm_eu_fence_buffer_objects(struct ww_acquire_ctx * ticket,struct list_head * list,struct dma_fence * fence)145 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
146 struct list_head *list,
147 struct dma_fence *fence)
148 {
149 struct ttm_validate_buffer *entry;
150
151 if (list_empty(list))
152 return;
153
154 list_for_each_entry(entry, list, head) {
155 struct ttm_buffer_object *bo = entry->bo;
156
157 dma_resv_add_fence(bo->base.resv, fence, entry->num_shared ?
158 DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE);
159 ttm_bo_move_to_lru_tail_unlocked(bo);
160 dma_resv_unlock(bo->base.resv);
161 }
162 if (ticket)
163 ww_acquire_fini(ticket);
164 }
165 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
166