diff options
| -rw-r--r-- | include/linux/lockref.h | 1 | ||||
| -rw-r--r-- | lib/lockref.c | 28 |
2 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/lockref.h b/include/linux/lockref.h index 2eac32095113..99f17cc8e163 100644 --- a/include/linux/lockref.h +++ b/include/linux/lockref.h @@ -37,6 +37,7 @@ struct lockref { extern void lockref_get(struct lockref *); extern int lockref_put_return(struct lockref *); extern int lockref_get_not_zero(struct lockref *); +extern int lockref_put_not_zero(struct lockref *); extern int lockref_get_or_lock(struct lockref *); extern int lockref_put_or_lock(struct lockref *); diff --git a/lib/lockref.c b/lib/lockref.c index 47169ed7e964..3d468b53d4c9 100644 --- a/lib/lockref.c +++ b/lib/lockref.c @@ -81,6 +81,34 @@ int lockref_get_not_zero(struct lockref *lockref) EXPORT_SYMBOL(lockref_get_not_zero); /** + * lockref_put_not_zero - Decrements count unless count <= 1 before decrement + * @lockref: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if count would become zero + */ +int lockref_put_not_zero(struct lockref *lockref) +{ + int retval; + + CMPXCHG_LOOP( + new.count--; + if (old.count <= 1) + return 0; + , + return 1; + ); + + spin_lock(&lockref->lock); + retval = 0; + if (lockref->count > 1) { + lockref->count--; + retval = 1; + } + spin_unlock(&lockref->lock); + return retval; +} +EXPORT_SYMBOL(lockref_put_not_zero); + +/** * lockref_get_or_lock - Increments count unless the count is 0 or dead * @lockref: pointer to lockref structure * Return: 1 if count updated successfully or 0 if count was zero |