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{
98	struct ttm_bo_global *glob;
99	struct ttm_validate_buffer *entry;
100	int ret;
101
102	if (list_empty(list))
103		return 0;
104
105	entry = list_first_entry(list, struct ttm_validate_buffer, head);
106	glob = entry->bo->glob;
107
108	if (ticket)
109		ww_acquire_init(ticket, &reservation_ww_class);
110
111	list_for_each_entry(entry, list, head) {
112		struct ttm_buffer_object *bo = entry->bo;
113
114		ret = __ttm_bo_reserve(bo, intr, (ticket == NULL), true,
115				       ticket);
116		if (!ret && unlikely(atomic_read(&bo->cpu_writers) > 0)) {
117			__ttm_bo_unreserve(bo);
118
119			ret = -EBUSY;
120		}
121
122		if (!ret) {
123			if (!entry->shared)
124				continue;
125
126			ret = reservation_object_reserve_shared(bo->resv);
127			if (!ret)
128				continue;
129		}
130
131		/* uh oh, we lost out, drop every reservation and try
132		 * to only reserve this buffer, then start over if
133		 * this succeeds.
134		 */
135		ttm_eu_backoff_reservation_reverse(list, entry);
136
137		if (ret == -EDEADLK && intr) {
138			ret = ww_mutex_lock_slow_interruptible(&bo->resv->lock,
139							       ticket);
140		} else if (ret == -EDEADLK) {
141			ww_mutex_lock_slow(&bo->resv->lock, ticket);
142			ret = 0;
143		}
144
145		if (!ret && entry->shared)
146			ret = reservation_object_reserve_shared(bo->resv);
147
148		if (unlikely(ret != 0)) {
149			if (ret == -EINTR)
150				ret = -ERESTARTSYS;
151			if (ticket) {
152				ww_acquire_done(ticket);
153				ww_acquire_fini(ticket);
154			}
155			return ret;
156		}
157
158		/* move this item to the front of the list,
159		 * forces correct iteration of the loop without keeping track
160		 */
161		list_del(&entry->head);
162		list_add(&entry->head, list);
163	}
164
165	if (ticket)
166		ww_acquire_done(ticket);
167	spin_lock(&glob->lru_lock);
168	ttm_eu_del_from_lru_locked(list);
169	spin_unlock(&glob->lru_lock);
170	return 0;
171}
172EXPORT_SYMBOL(ttm_eu_reserve_buffers);
173
174void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
175				 struct list_head *list, struct fence *fence)
176{
177	struct ttm_validate_buffer *entry;
178	struct ttm_buffer_object *bo;
179	struct ttm_bo_global *glob;
180	struct ttm_bo_device *bdev;
181	struct ttm_bo_driver *driver;
182
183	if (list_empty(list))
184		return;
185
186	bo = list_first_entry(list, struct ttm_validate_buffer, head)->bo;
187	bdev = bo->bdev;
188	driver = bdev->driver;
189	glob = bo->glob;
190
191	spin_lock(&glob->lru_lock);
192
193	list_for_each_entry(entry, list, head) {
194		bo = entry->bo;
195		if (entry->shared)
196			reservation_object_add_shared_fence(bo->resv, fence);
197		else
198			reservation_object_add_excl_fence(bo->resv, fence);
199		ttm_bo_add_to_lru(bo);
200		__ttm_bo_unreserve(bo);
201	}
202	spin_unlock(&glob->lru_lock);
203	if (ticket)
204		ww_acquire_fini(ticket);
205}
206EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
207