diff options
| author | Jerome Marchand <jmarchan@redhat.com> | 2011-01-05 16:57:37 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-02-17 15:14:17 -0800 |
| commit | 07384b42b672c8ea266ea4ba50c5e50c9323ae9f (patch) | |
| tree | 6dd77da4aa14e5e090c89c75f3625e22c87ee74b | |
| parent | c4b03cd47360e5eb751adf2a5f96e7edcfde9821 (diff) | |
kref: add kref_test_and_get
commit e4a683c899cd5a49f8d684a054c95bd115a0c005 upstream.
Add kref_test_and_get() function, which atomically add a reference only if
refcount is not zero. This prevent to add a reference to an object that is
already being removed.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | include/linux/kref.h | 1 | ||||
| -rw-r--r-- | lib/kref.c | 12 |
2 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h index 6cc38fc07ab..90b9e44abf5 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -23,6 +23,7 @@ struct kref { void kref_init(struct kref *kref); void kref_get(struct kref *kref); +int kref_test_and_get(struct kref *kref); int kref_put(struct kref *kref, void (*release) (struct kref *kref)); #endif /* _KREF_H_ */ diff --git a/lib/kref.c b/lib/kref.c index d3d227a08a4..e7a6e106712 100644 --- a/lib/kref.c +++ b/lib/kref.c @@ -37,6 +37,18 @@ void kref_get(struct kref *kref) } /** + * kref_test_and_get - increment refcount for object only if refcount is not + * zero. + * @kref: object. + * + * Return non-zero if the refcount was incremented, 0 otherwise + */ +int kref_test_and_get(struct kref *kref) +{ + return atomic_inc_not_zero(&kref->refcount); +} + +/** * kref_put - decrement refcount for object. * @kref: object. * @release: pointer to the function that will clean up the object when the |