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/include/linux/spinlock_up.h

https://github.com/airy09/android_kernel_sony_apq8064
C Header | 78 lines | 47 code | 16 blank | 15 comment | 9 complexity | 4f33236e6d8041721c373993d21e71b1 MD5 | raw file
 1#ifndef __LINUX_SPINLOCK_UP_H
 2#define __LINUX_SPINLOCK_UP_H
 3
 4#ifndef __LINUX_SPINLOCK_H
 5# error "please don't include this file directly"
 6#endif
 7
 8#include <asm/processor.h>	/* for cpu_relax() */
 9
10/*
11 * include/linux/spinlock_up.h - UP-debug version of spinlocks.
12 *
13 * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
14 * Released under the General Public License (GPL).
15 *
16 * In the debug case, 1 means unlocked, 0 means locked. (the values
17 * are inverted, to catch initialization bugs)
18 *
19 * No atomicity anywhere, we are on UP.
20 */
21
22#ifdef CONFIG_DEBUG_SPINLOCK
23#define arch_spin_is_locked(x)		((x)->slock == 0)
24
25static inline void arch_spin_lock(arch_spinlock_t *lock)
26{
27	lock->slock = 0;
28}
29
30static inline void
31arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
32{
33	local_irq_save(flags);
34	lock->slock = 0;
35}
36
37static inline int arch_spin_trylock(arch_spinlock_t *lock)
38{
39	char oldval = lock->slock;
40
41	lock->slock = 0;
42
43	return oldval > 0;
44}
45
46static inline void arch_spin_unlock(arch_spinlock_t *lock)
47{
48	lock->slock = 1;
49}
50
51/*
52 * Read-write spinlocks. No debug version.
53 */
54#define arch_read_lock(lock)		do { (void)(lock); } while (0)
55#define arch_write_lock(lock)		do { (void)(lock); } while (0)
56#define arch_read_trylock(lock)	({ (void)(lock); 1; })
57#define arch_write_trylock(lock)	({ (void)(lock); 1; })
58#define arch_read_unlock(lock)		do { (void)(lock); } while (0)
59#define arch_write_unlock(lock)	do { (void)(lock); } while (0)
60
61#else /* DEBUG_SPINLOCK */
62#define arch_spin_is_locked(lock)	((void)(lock), 0)
63/* for sched.c and kernel_lock.c: */
64# define arch_spin_lock(lock)		do { (void)(lock); } while (0)
65# define arch_spin_lock_flags(lock, flags)	do { (void)(lock); } while (0)
66# define arch_spin_unlock(lock)	do { (void)(lock); } while (0)
67# define arch_spin_trylock(lock)	({ (void)(lock); 1; })
68#endif /* DEBUG_SPINLOCK */
69
70#define arch_spin_is_contended(lock)	(((void)(lock), 0))
71
72#define arch_read_can_lock(lock)	(((void)(lock), 1))
73#define arch_write_can_lock(lock)	(((void)(lock), 1))
74
75#define arch_spin_unlock_wait(lock) \
76		do { cpu_relax(); } while (arch_spin_is_locked(lock))
77
78#endif /* __LINUX_SPINLOCK_UP_H */