net, ipx: convert ipx_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/ipx/ipx_route.c b/net/ipx/ipx_route.c
index 3e2a32a..b5d9144 100644
--- a/net/ipx/ipx_route.c
+++ b/net/ipx/ipx_route.c
@@ -59,7 +59,7 @@
 		if (!rt)
 			goto out;
 
-		atomic_set(&rt->refcnt, 1);
+		refcount_set(&rt->refcnt, 1);
 		ipxrtr_hold(rt);
 		write_lock_bh(&ipx_routes_lock);
 		list_add(&rt->node, &ipx_routes);