1 /* $NetBSD: ttm_execbuf_util.c,v 1.6 2021/12/18 23:45:44 riastradh Exp $ */
2
3 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
4 /**************************************************************************
5 *
6 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
7 * All Rights Reserved.
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the
11 * "Software"), to deal in the Software without restriction, including
12 * without limitation the rights to use, copy, modify, merge, publish,
13 * distribute, sub license, and/or sell copies of the Software, and to
14 * permit persons to whom the Software is furnished to do so, subject to
15 * the following conditions:
16 *
17 * The above copyright notice and this permission notice (including the
18 * next paragraph) shall be included in all copies or substantial portions
19 * of the Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
24 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
25 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
26 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
27 * USE OR OTHER DEALINGS IN THE SOFTWARE.
28 *
29 **************************************************************************/
30
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: ttm_execbuf_util.c,v 1.6 2021/12/18 23:45:44 riastradh Exp $");
33
34 #include <drm/ttm/ttm_execbuf_util.h>
35 #include <drm/ttm/ttm_bo_driver.h>
36 #include <drm/ttm/ttm_placement.h>
37 #include <linux/wait.h>
38 #include <linux/sched.h>
39 #include <linux/module.h>
40
ttm_eu_backoff_reservation_reverse(struct list_head * list,struct ttm_validate_buffer * entry)41 static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
42 struct ttm_validate_buffer *entry)
43 {
44 list_for_each_entry_continue_reverse(entry, list, head) {
45 struct ttm_buffer_object *bo = entry->bo;
46
47 dma_resv_unlock(bo->base.resv);
48 }
49 }
50
ttm_eu_backoff_reservation(struct ww_acquire_ctx * ticket,struct list_head * list)51 void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
52 struct list_head *list)
53 {
54 struct ttm_validate_buffer *entry;
55
56 if (list_empty(list))
57 return;
58
59 spin_lock(&ttm_bo_glob.lru_lock);
60 list_for_each_entry(entry, list, head) {
61 struct ttm_buffer_object *bo = entry->bo;
62
63 ttm_bo_move_to_lru_tail(bo, NULL);
64 dma_resv_unlock(bo->base.resv);
65 }
66 spin_unlock(&ttm_bo_glob.lru_lock);
67
68 if (ticket)
69 ww_acquire_fini(ticket);
70 }
71 EXPORT_SYMBOL(ttm_eu_backoff_reservation);
72
73 /*
74 * Reserve buffers for validation.
75 *
76 * If a buffer in the list is marked for CPU access, we back off and
77 * wait for that buffer to become free for GPU access.
78 *
79 * If a buffer is reserved for another validation, the validator with
80 * the highest validation sequence backs off and waits for that buffer
81 * to become unreserved. This prevents deadlocks when validating multiple
82 * buffers in different orders.
83 */
84
ttm_eu_reserve_buffers(struct ww_acquire_ctx * ticket,struct list_head * list,bool intr,struct list_head * dups)85 int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
86 struct list_head *list, bool intr,
87 struct list_head *dups)
88 {
89 struct ttm_validate_buffer *entry;
90 int ret;
91
92 if (list_empty(list))
93 return 0;
94
95 if (ticket)
96 ww_acquire_init(ticket, &reservation_ww_class);
97
98 list_for_each_entry(entry, list, head) {
99 struct ttm_buffer_object *bo = entry->bo;
100
101 ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
102 if (ret == -EALREADY && dups) {
103 struct ttm_validate_buffer *safe = entry;
104 entry = list_prev_entry(entry, head);
105 list_del(&safe->head);
106 list_add(&safe->head, dups);
107 continue;
108 }
109
110 if (!ret) {
111 if (!entry->num_shared)
112 continue;
113
114 ret = dma_resv_reserve_shared(bo->base.resv,
115 entry->num_shared);
116 if (!ret)
117 continue;
118 }
119
120 /* uh oh, we lost out, drop every reservation and try
121 * to only reserve this buffer, then start over if
122 * this succeeds.
123 */
124 ttm_eu_backoff_reservation_reverse(list, entry);
125
126 if (ret == -EDEADLK) {
127 if (intr) {
128 ret = dma_resv_lock_slow_interruptible(bo->base.resv,
129 ticket);
130 } else {
131 dma_resv_lock_slow(bo->base.resv, ticket);
132 ret = 0;
133 }
134 }
135
136 if (!ret && entry->num_shared)
137 ret = dma_resv_reserve_shared(bo->base.resv,
138 entry->num_shared);
139
140 if (unlikely(ret != 0)) {
141 if (ret == -EINTR)
142 ret = -ERESTARTSYS;
143 if (ticket) {
144 ww_acquire_done(ticket);
145 ww_acquire_fini(ticket);
146 }
147 return ret;
148 }
149
150 /* move this item to the front of the list,
151 * forces correct iteration of the loop without keeping track
152 */
153 list_del(&entry->head);
154 list_add(&entry->head, list);
155 }
156
157 return 0;
158 }
159 EXPORT_SYMBOL(ttm_eu_reserve_buffers);
160
ttm_eu_fence_buffer_objects(struct ww_acquire_ctx * ticket,struct list_head * list,struct dma_fence * fence)161 void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
162 struct list_head *list,
163 struct dma_fence *fence)
164 {
165 struct ttm_validate_buffer *entry;
166
167 if (list_empty(list))
168 return;
169
170 spin_lock(&ttm_bo_glob.lru_lock);
171 list_for_each_entry(entry, list, head) {
172 struct ttm_buffer_object *bo = entry->bo;
173
174 if (entry->num_shared)
175 dma_resv_add_shared_fence(bo->base.resv, fence);
176 else
177 dma_resv_add_excl_fence(bo->base.resv, fence);
178 ttm_bo_move_to_lru_tail(bo, NULL);
179 dma_resv_unlock(bo->base.resv);
180 }
181 spin_unlock(&ttm_bo_glob.lru_lock);
182 if (ticket)
183 ww_acquire_fini(ticket);
184 }
185 EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
186