lockref: Add lockref_put_not_zero
Put a lockref unless the lockref is dead or its count would become zero. This is the same as lockref_put_or_lock except that the lock is never left held. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
parent
e241e3f2bf
commit
450b1f6f56
2 changed files with 29 additions and 0 deletions
|
@ -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 *);
|
||||
|
||||
|
|
|
@ -80,6 +80,34 @@ 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
|
||||
|
|
Loading…
Reference in a new issue