From 8ad5db8a8ddbe3bd33078863a027011e28f1f4ee Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 17 Aug 2012 20:10:46 -0400 Subject: [PATCH] introduce kref_put_mutex() equivalent of mutex_lock(mutex); if (!kref_put(kref, release)) mutex_unlock(mutex); Signed-off-by: Al Viro --- include/linux/kref.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/include/linux/kref.h b/include/linux/kref.h index 9c07dcebded7..65af6887872f 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -18,6 +18,7 @@ #include #include #include +#include struct kref { atomic_t refcount; @@ -93,4 +94,21 @@ static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref) { return kref_sub(kref, 1, release); } + +static inline int kref_put_mutex(struct kref *kref, + void (*release)(struct kref *kref), + struct mutex *lock) +{ + WARN_ON(release == NULL); + if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) { + mutex_lock(lock); + if (unlikely(!atomic_dec_and_test(&kref->refcount))) { + mutex_unlock(lock); + return 0; + } + release(kref); + return 1; + } + return 0; +} #endif /* _KREF_H_ */ -- 2.30.2