diff options
Diffstat (limited to 'include/asm-mips/semaphore.h')
| -rw-r--r-- | include/asm-mips/semaphore.h | 52 |
1 files changed, 45 insertions, 7 deletions
diff --git a/include/asm-mips/semaphore.h b/include/asm-mips/semaphore.h index f093fe519..6d527848b 100644 --- a/include/asm-mips/semaphore.h +++ b/include/asm-mips/semaphore.h @@ -14,23 +14,61 @@ struct semaphore { atomic_t count; - atomic_t waiting; + atomic_t waking; struct wait_queue * wait; }; -#define MUTEX ((struct semaphore) { 1, 0, NULL }) -#define MUTEX_LOCKED ((struct semaphore) { 0, 0, NULL }) +#define MUTEX ((struct semaphore) { ATOMIC_INIT(1), ATOMIC_INIT(0), NULL }) +#define MUTEX_LOCKED ((struct semaphore) { ATOMIC_INIT(0), ATOMIC_INIT(0), NULL }) extern void __down(struct semaphore * sem); +extern int __down_interruptible(struct semaphore * sem); extern void __up(struct semaphore * sem); +#define sema_init(sem, val) atomic_set(&((sem)->count), val) + +/* + * These two _must_ execute atomically wrt each other. + * + * This is trivially done with load_locked/store_cond, + * which we have. Let the rest of the losers suck eggs. + */ + +static inline void wake_one_more(struct semaphore * sem) +{ + atomic_inc(&sem->waking); +} + +static inline int waking_non_zero(struct semaphore *sem) +{ + int ret, tmp; + + __asm__ __volatile__( + "1:\tll\t%1,%2\n" + "blez\t%1,2f\n\t" + "subu\t%0,%1,1\n\t" + "sc\t%0,%2\n\t" + "beqz\t%0,1b\n\t" + "2:" + ".text" + : "=r"(ret), "=r"(tmp), "=m"(__atomic_fool_gcc(&sem->waking)) + : "0"(0)); + + return ret; +} + extern inline void down(struct semaphore * sem) { - while (1) { - if (atomic_dec_return(&sem->count) >= 0) - break; + if (atomic_dec_return(&sem->count) < 0) __down(sem); - } +} + +extern inline int down_interruptible(struct semaphore * sem) +{ + int ret = 0; + if (atomic_dec_return(&sem->count) < 0) + ret = __down_interruptible(sem); + return ret; } /* |