1/**************************************************************************
2 *
3 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28#include <drm/ttm/ttm_execbuf_util.h>
29#include <drm/ttm/ttm_bo_driver.h>
30#include <drm/ttm/ttm_placement.h>
31#include <linux/wait.h>
32#include <linux/sched.h>
33#include <linux/module.h>
34
35static void ttm_eu_backoff_reservation_reverse(struct list_head *list,
36					      struct ttm_validate_buffer *entry)
37{
38	list_for_each_entry_continue_reverse(entry, list, head) {
39		struct ttm_buffer_object *bo = entry->bo;
40
41		__ttm_bo_unreserve(bo);
42	}
43}
44
45static void ttm_eu_del_from_lru_locked(struct list_head *list)
46{
47	struct ttm_validate_buffer *entry;
48
49	list_for_each_entry(entry, list, head) {
50		struct ttm_buffer_object *bo = entry->bo;
51		unsigned put_count = ttm_bo_del_from_lru(bo);
52
53		ttm_bo_list_ref_sub(bo, put_count, true);
54	}
55}
56
57void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
58				struct list_head *list)
59{
60	struct ttm_validate_buffer *entry;
61	struct ttm_bo_global *glob;
62
63	if (list_empty(list))
64		return;
65
66	entry = list_first_entry(list, struct ttm_validate_buffer, head);
67	glob = entry->bo->glob;
68
69	spin_lock(&glob->lru_lock);
70	list_for_each_entry(entry, list, head) {
71		struct ttm_buffer_object *bo = entry->bo;
72
73		ttm_bo_add_to_lru(bo);
74		__ttm_bo_unreserve(bo);
75	}
76	spin_unlock(&glob->lru_lock);
77
78	if (ticket)
79		ww_acquire_fini(ticket);
80}
81EXPORT_SYMBOL(ttm_eu_backoff_reservation);
82
83/*
84 * Reserve buffers for validation.
85 *
86 * If a buffer in the list is marked for CPU access, we back off and
87 * wait for that buffer to become free for GPU access.
88 *
89 * If a buffer is reserved for another validation, the validator with
90 * the highest validation sequence backs off and waits for that buffer
91 * to become unreserved. This prevents deadlocks when validating multiple
92 * buffers in different orders.
93 */
94
95int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
96			   struct list_head *list, bool intr,
97			   struct list_head *dups)
98{
99	struct ttm_bo_global *glob;
100	struct ttm_validate_buffer *entry;
101	int ret;
102
103	if (list_empty(list))
104		return 0;
105
106	entry = list_first_entry(list, struct ttm_validate_buffer, head);
107	glob = entry->bo->glob;
108
109	if (ticket)
110		ww_acquire_init(ticket, &reservation_ww_class);
111
112	list_for_each_entry(entry, list, head) {
113		struct ttm_buffer_object *bo = entry->bo;
114
115		ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), true,
116				       ticket);
117		if (!ret && unlikely(atomic_read(&bo->cpu_writers) > 0)) {
118			__ttm_bo_unreserve(bo);
119
120			ret = -EBUSY;
121
122		} else if (ret == -EALREADY && dups) {
123			struct ttm_validate_buffer *safe = entry;
124			entry = list_prev_entry(entry, head);
125			list_del(&safe->head);
126			list_add(&safe->head, dups);
127			continue;
128		}
129
130		if (!ret) {
131			if (!entry->shared)
132				continue;
133
134			ret = reservation_object_reserve_shared(bo->resv);
135			if (!ret)
136				continue;
137		}
138
139		/* uh oh, we lost out, drop every reservation and try
140		 * to only reserve this buffer, then start over if
141		 * this succeeds.
142		 */
143		ttm_eu_backoff_reservation_reverse(list, entry);
144
145		if (ret == -EDEADLK && intr) {
146			ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
147							       ticket);
148		} else if (ret == -EDEADLK) {
149			ww_mutex_lock_slow(&bo->resv->lock, ticket);
150			ret = 0;
151		}
152
153		if (!ret && entry->shared)
154			ret = reservation_object_reserve_shared(bo->resv);
155
156		if (unlikely(ret != 0)) {
157			if (ret == -EINTR)
158				ret = -ERESTARTSYS;
159			if (ticket) {
160				ww_acquire_done(ticket);
161				ww_acquire_fini(ticket);
162			}
163			return ret;
164		}
165
166		/* move this item to the front of the list,
167		 * forces correct iteration of the loop without keeping track
168		 */
169		list_del(&entry->head);
170		list_add(&entry->head, list);
171	}
172
173	if (ticket)
174		ww_acquire_done(ticket);
175	spin_lock(&glob->lru_lock);
176	ttm_eu_del_from_lru_locked(list);
177	spin_unlock(&glob->lru_lock);
178	return 0;
179}
180EXPORT_SYMBOL(ttm_eu_reserve_buffers);
181
182void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
183				 struct list_head *list, struct fence *fence)
184{
185	struct ttm_validate_buffer *entry;
186	struct ttm_buffer_object *bo;
187	struct ttm_bo_global *glob;
188	struct ttm_bo_device *bdev;
189	struct ttm_bo_driver *driver;
190
191	if (list_empty(list))
192		return;
193
194	bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
195	bdev = bo->bdev;
196	driver = bdev->driver;
197	glob = bo->glob;
198
199	spin_lock(&glob->lru_lock);
200
201	list_for_each_entry(entry, list, head) {
202		bo = entry->bo;
203		if (entry->shared)
204			reservation_object_add_shared_fence(bo->resv, fence);
205		else
206			reservation_object_add_excl_fence(bo->resv, fence);
207		ttm_bo_add_to_lru(bo);
208		__ttm_bo_unreserve(bo);
209	}
210	spin_unlock(&glob->lru_lock);
211	if (ticket)
212		ww_acquire_fini(ticket);
213}
214EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
215