summaryrefslogtreecommitdiffstats
path: root/include/linux/spinlock_up.h
blob: 938234c4a996ba6e78521ffc60ecc197034fed9d (plain) (blame)
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
#ifndef __LINUX_SPINLOCK_UP_H
#define __LINUX_SPINLOCK_UP_H

#ifndef __LINUX_SPINLOCK_H
# error "please don't include this file directly"
#endif

/*
 * include/linux/spinlock_up.h - UP-debug version of spinlocks.
 *
 * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
 * Released under the General Public License (GPL).
 *
 * In the debug case, 1 means unlocked, 0 means locked. (the values
 * are inverted, to catch initialization bugs)
 *
 * No atomicity anywhere, we are on UP.
 */

#ifdef CONFIG_DEBUG_SPINLOCK
#define __raw_spin_is_locked(x)		((x)->slock == 0)

static inline void __raw_spin_lock(raw_spinlock_t *lock)
{
	lock->slock = 0;
}

static inline void
__raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
{
	local_irq_save(flags);
	lock->slock = 0;
}

static inline int __raw_spin_trylock(raw_spinlock_t *lock)
{
	char oldval = lock->slock;

	lock->slock = 0;

	return oldval > 0;
}

static inline void __raw_spin_unlock(raw_spinlock_t *lock)
{
	lock->slock = 1;
}

/*
 * Read-write spinlocks. No debug version.
 */
#define __raw_read_lock(lock)		do { (void)(lock); } while (0)
#define __raw_write_lock(lock)		do { (void)(lock); } while (0)
#define __raw_read_trylock(lock)	({ (void)(lock); 1; })
#define __raw_write_trylock(lock)	({ (void)(lock); 1; })
#define __raw_read_unlock(lock)		do { (void)(lock); } while (0)
#define __raw_write_unlock(lock)	do { (void)(lock); } while (0)

#else /* DEBUG_SPINLOCK */
#define __raw_spin_is_locked(lock)	((void)(lock), 0)
/* for sched.c and kernel_lock.c: */
# define __raw_spin_lock(lock)		do { (void)(lock); } while (0)
# define __raw_spin_unlock(lock)	do { (void)(lock); } while (0)
# define __raw_spin_trylock(lock)	({ (void)(lock); 1; })
#endif /* DEBUG_SPINLOCK */

#define __raw_spin_is_contended(lock)	(((void)(lock), 0))

#define __raw_read_can_lock(lock)	(((void)(lock), 1))
#define __raw_write_can_lock(lock)	(((void)(lock), 1))

#define __raw_spin_unlock_wait(lock) \
		do { cpu_relax(); } while (__raw_spin_is_locked(lock))

#endif /* __LINUX_SPINLOCK_UP_H */