blob: 2804fc44911ed60722a85fd43abaa181c5f4706b (
plain)
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
|
/*
* Copyright (c) 2013-2017 Richard Braun.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* Mutual exclusion sleep locks.
*
* Unlike spin locks, acquiring a mutex may make the calling thread sleep.
*
* TODO Adaptive spinning.
*/
#ifndef _KERN_MUTEX_H
#define _KERN_MUTEX_H
#include <kern/assert.h>
#include <kern/error.h>
#include <kern/mutex_i.h>
#include <kern/mutex_types.h>
#include <kern/thread.h>
struct mutex;
#define mutex_assert_locked(mutex) assert((mutex)->state != MUTEX_UNLOCKED)
/*
* Initialize a mutex.
*/
static inline void
mutex_init(struct mutex *mutex)
{
mutex->state = MUTEX_UNLOCKED;
}
/*
* Attempt to lock the given mutex.
*
* This function may not sleep.
*
* Return 0 on success, ERROR_BUSY if the mutex is already locked.
*/
static inline int
mutex_trylock(struct mutex *mutex)
{
unsigned int state;
state = mutex_tryacquire(mutex);
if (state == MUTEX_UNLOCKED) {
return 0;
}
return ERROR_BUSY;
}
/*
* Lock a mutex.
*
* If the mutex is already locked, the calling thread sleeps until the
* mutex is unlocked.
*
* A mutex can only be locked once.
*/
static inline void
mutex_lock(struct mutex *mutex)
{
unsigned int state;
state = mutex_tryacquire(mutex);
if (state == MUTEX_UNLOCKED) {
return;
}
assert((state == MUTEX_LOCKED) || (state == MUTEX_CONTENDED));
mutex_lock_slow(mutex);
}
/*
* Unlock a mutex.
*
* The mutex must be locked, and must have been locked by the calling
* thread.
*/
static inline void
mutex_unlock(struct mutex *mutex)
{
unsigned int state;
state = mutex_release(mutex);
if (state != MUTEX_LOCKED) {
assert(state == MUTEX_CONTENDED);
mutex_unlock_slow(mutex);
}
/*
* If this mutex was used along with a condition variable, wake up
* a potential pending waiter.
*/
thread_wakeup_last_cond();
}
#endif /* _KERN_MUTEX_H */
|
