2.6.37-stable review patch. If anyone has any objections, please let us know.
------------------ From: Jerome Marchand <[email protected]> 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 <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- include/linux/kref.h | 1 + lib/kref.c | 12 ++++++++++++ 2 files changed, 13 insertions(+) --- 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_ */ --- 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 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
