net, x25: convert x25_route.refcnt 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/x25/x25_route.c b/net/x25/x25_route.c
index 277c8d2..b85b889 100644
--- a/net/x25/x25_route.c
+++ b/net/x25/x25_route.c
@@ -55,7 +55,7 @@
 
 	rt->sigdigits = sigdigits;
 	rt->dev       = dev;
-	atomic_set(&rt->refcnt, 1);
+	refcount_set(&rt->refcnt, 1);
 
 	list_add(&rt->node, &x25_route_list);
 	rc = 0;