net, netrom: convert nr_node.refcount 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: David S. Miller <davem@davemloft.net>
diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index 6b72970..0c59354 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -184,7 +184,7 @@ static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
 
 		nr_node->which = 0;
 		nr_node->count = 1;
-		atomic_set(&nr_node->refcount, 1);
+		refcount_set(&nr_node->refcount, 1);
 		spin_lock_init(&nr_node->node_lock);
 
 		nr_node->routes[0].quality   = quality;