mutex-dec.h

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/*
 * include/asm-generic/mutex-dec.h
 *
 * Generic implementation of the mutex fastpath, based on atomic
 * decrement/increment.
 */
#ifndef _ASM_GENERIC_MUTEX_DEC_H
#define _ASM_GENERIC_MUTEX_DEC_H

static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
    if (unlikely(atomic_dec_return(count) < 0))
        fail_fn(count);
}

static inline int
__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
{
    if (unlikely(atomic_dec_return(count) < 0))
        return fail_fn(count);
    return 0;
}

static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
    if (unlikely(atomic_inc_return(count) <= 0))
        fail_fn(count);
}

#define __mutex_slowpath_needs_to_unlock()      1

static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
    if (likely(atomic_cmpxchg(count, 1, 0) == 1))
        return 1;
    return 0;
}

#endif