1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/**************************************************************************
*
* Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/*
* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*/
/** @file ttm_lock.h
* This file implements a simple replacement for the buffer manager use
* of the DRM heavyweight hardware lock.
* The lock is a read-write lock. Taking it in read mode and write mode
* is relatively fast, and intended for in-kernel use only.
*
* The vt mode is used only when there is a need to block all
* user-space processes from validating buffers.
* It's allowed to leave kernel space with the vt lock held.
* If a user-space process dies while having the vt-lock,
* it will be released during the file descriptor release. The vt lock
* excludes write lock and read lock.
*
* The suspend mode is used to lock out all TTM users when preparing for
* and executing suspend operations.
*
*/
#ifndef _TTM_LOCK_H_
#define _TTM_LOCK_H_
#include "ttm/ttm_object.h"
#include <linux/wait.h>
#include <linux/atomic.h>
/**
* struct ttm_lock
*
* @base: ttm base object used solely to release the lock if the client
* holding the lock dies.
* @queue: Queue for processes waiting for lock change-of-status.
* @lock: Spinlock protecting some lock members.
* @rw: Read-write lock counter. Protected by @lock.
* @flags: Lock state. Protected by @lock.
* @kill_takers: Boolean whether to kill takers of the lock.
* @signal: Signal to send when kill_takers is true.
*/
struct ttm_lock {
struct ttm_base_object base;
wait_queue_head_t queue;
spinlock_t lock;
int32_t rw;
uint32_t flags;
bool kill_takers;
int signal;
struct ttm_object_file *vt_holder;
};
/**
* ttm_lock_init
*
* @lock: Pointer to a struct ttm_lock
* Initializes the lock.
*/
extern void ttm_lock_init(struct ttm_lock *lock);
/**
* ttm_read_unlock
*
* @lock: Pointer to a struct ttm_lock
*
* Releases a read lock.
*/
extern void ttm_read_unlock(struct ttm_lock *lock);
/**
* ttm_read_lock
*
* @lock: Pointer to a struct ttm_lock
* @interruptible: Interruptible sleeping while waiting for a lock.
*
* Takes the lock in read mode.
* Returns:
* -ERESTARTSYS If interrupted by a signal and interruptible is true.
*/
extern int ttm_read_lock(struct ttm_lock *lock, bool interruptible);
/**
* ttm_read_trylock
*
* @lock: Pointer to a struct ttm_lock
* @interruptible: Interruptible sleeping while waiting for a lock.
*
* Tries to take the lock in read mode. If the lock is already held
* in write mode, the function will return -EBUSY. If the lock is held
* in vt or suspend mode, the function will sleep until these modes
* are unlocked.
*
* Returns:
* -EBUSY The lock was already held in write mode.
* -ERESTARTSYS If interrupted by a signal and interruptible is true.
*/
extern int ttm_read_trylock(struct ttm_lock *lock, bool interruptible);
/**
* ttm_write_unlock
*
* @lock: Pointer to a struct ttm_lock
*
* Releases a write lock.
*/
extern void ttm_write_unlock(struct ttm_lock *lock);
/**
* ttm_write_lock
*
* @lock: Pointer to a struct ttm_lock
* @interruptible: Interruptible sleeping while waiting for a lock.
*
* Takes the lock in write mode.
* Returns:
* -ERESTARTSYS If interrupted by a signal and interruptible is true.
*/
extern int ttm_write_lock(struct ttm_lock *lock, bool interruptible);
/**
* ttm_lock_downgrade
*
* @lock: Pointer to a struct ttm_lock
*
* Downgrades a write lock to a read lock.
*/
extern void ttm_lock_downgrade(struct ttm_lock *lock);
/**
* ttm_suspend_lock
*
* @lock: Pointer to a struct ttm_lock
*
* Takes the lock in suspend mode. Excludes read and write mode.
*/
extern void ttm_suspend_lock(struct ttm_lock *lock);
/**
* ttm_suspend_unlock
*
* @lock: Pointer to a struct ttm_lock
*
* Releases a suspend lock
*/
extern void ttm_suspend_unlock(struct ttm_lock *lock);
/**
* ttm_vt_lock
*
* @lock: Pointer to a struct ttm_lock
* @interruptible: Interruptible sleeping while waiting for a lock.
* @tfile: Pointer to a struct ttm_object_file to register the lock with.
*
* Takes the lock in vt mode.
* Returns:
* -ERESTARTSYS If interrupted by a signal and interruptible is true.
* -ENOMEM: Out of memory when locking.
*/
extern int ttm_vt_lock(struct ttm_lock *lock, bool interruptible,
struct ttm_object_file *tfile);
/**
* ttm_vt_unlock
*
* @lock: Pointer to a struct ttm_lock
*
* Releases a vt lock.
* Returns:
* -EINVAL If the lock was not held.
*/
extern int ttm_vt_unlock(struct ttm_lock *lock);
/**
* ttm_write_unlock
*
* @lock: Pointer to a struct ttm_lock
*
* Releases a write lock.
*/
extern void ttm_write_unlock(struct ttm_lock *lock);
/**
* ttm_write_lock
*
* @lock: Pointer to a struct ttm_lock
* @interruptible: Interruptible sleeping while waiting for a lock.
*
* Takes the lock in write mode.
* Returns:
* -ERESTARTSYS If interrupted by a signal and interruptible is true.
*/
extern int ttm_write_lock(struct ttm_lock *lock, bool interruptible);
/**
* ttm_lock_set_kill
*
* @lock: Pointer to a struct ttm_lock
* @val: Boolean whether to kill processes taking the lock.
* @signal: Signal to send to the process taking the lock.
*
* The kill-when-taking-lock functionality is used to kill processes that keep
* on using the TTM functionality when its resources has been taken down, for
* example when the X server exits. A typical sequence would look like this:
* - X server takes lock in write mode.
* - ttm_lock_set_kill() is called with @val set to true.
* - As part of X server exit, TTM resources are taken down.
* - X server releases the lock on file release.
* - Another dri client wants to render, takes the lock and is killed.
*
*/
static inline void ttm_lock_set_kill(struct ttm_lock *lock, bool val,
int signal)
{
lock->kill_takers = val;
if (val)
lock->signal = signal;
}
#endif
|
