libceph: convert ceph_snap_context.nref from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/net/ceph/snapshot.c b/net/ceph/snapshot.c
index 705414e..e14a5d0 100644
--- a/net/ceph/snapshot.c
+++ b/net/ceph/snapshot.c
@@ -49,7 +49,7 @@ struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
if (!snapc)
return NULL;
- atomic_set(&snapc->nref, 1);
+ refcount_set(&snapc->nref, 1);
snapc->num_snaps = snap_count;
return snapc;
@@ -59,7 +59,7 @@ EXPORT_SYMBOL(ceph_create_snap_context);
struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
{
if (sc)
- atomic_inc(&sc->nref);
+ refcount_inc(&sc->nref);
return sc;
}
EXPORT_SYMBOL(ceph_get_snap_context);
@@ -68,7 +68,7 @@ void ceph_put_snap_context(struct ceph_snap_context *sc)
{
if (!sc)
return;
- if (atomic_dec_and_test(&sc->nref)) {
+ if (refcount_dec_and_test(&sc->nref)) {
/*printk(" deleting snap_context %p\n", sc);*/
kfree(sc);
}
