Merge branch 'bugfixes' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
[linux-2.6.git] / include / linux / spinlock_up.h
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 /*
9  * include/linux/spinlock_up.h - UP-debug version of spinlocks.
10  *
11  * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
12  * Released under the General Public License (GPL).
13  *
14  * In the debug case, 1 means unlocked, 0 means locked. (the values
15  * are inverted, to catch initialization bugs)
16  *
17  * No atomicity anywhere, we are on UP.
18  */
19
20 #ifdef CONFIG_DEBUG_SPINLOCK
21 #define arch_spin_is_locked(x)          ((x)->slock == 0)
22
23 static inline void arch_spin_lock(arch_spinlock_t *lock)
24 {
25         lock->slock = 0;
26 }
27
28 static inline void
29 arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
30 {
31         local_irq_save(flags);
32         lock->slock = 0;
33 }
34
35 static inline int arch_spin_trylock(arch_spinlock_t *lock)
36 {
37         char oldval = lock->slock;
38
39         lock->slock = 0;
40
41         return oldval > 0;
42 }
43
44 static inline void arch_spin_unlock(arch_spinlock_t *lock)
45 {
46         lock->slock = 1;
47 }
48
49 /*
50  * Read-write spinlocks. No debug version.
51  */
52 #define arch_read_lock(lock)            do { (void)(lock); } while (0)
53 #define arch_write_lock(lock)           do { (void)(lock); } while (0)
54 #define arch_read_trylock(lock) ({ (void)(lock); 1; })
55 #define arch_write_trylock(lock)        ({ (void)(lock); 1; })
56 #define arch_read_unlock(lock)          do { (void)(lock); } while (0)
57 #define arch_write_unlock(lock) do { (void)(lock); } while (0)
58
59 #else /* DEBUG_SPINLOCK */
60 #define arch_spin_is_locked(lock)       ((void)(lock), 0)
61 /* for sched.c and kernel_lock.c: */
62 # define arch_spin_lock(lock)           do { (void)(lock); } while (0)
63 # define arch_spin_lock_flags(lock, flags)      do { (void)(lock); } while (0)
64 # define arch_spin_unlock(lock) do { (void)(lock); } while (0)
65 # define arch_spin_trylock(lock)        ({ (void)(lock); 1; })
66 #endif /* DEBUG_SPINLOCK */
67
68 #define arch_spin_is_contended(lock)    (((void)(lock), 0))
69
70 #define arch_read_can_lock(lock)        (((void)(lock), 1))
71 #define arch_write_can_lock(lock)       (((void)(lock), 1))
72
73 #define arch_spin_unlock_wait(lock) \
74                 do { cpu_relax(); } while (arch_spin_is_locked(lock))
75
76 #endif /* __LINUX_SPINLOCK_UP_H */