SUNRPC: compare scopeid for link-local addresses

For ipv6 link-local addresses, sunrpc do not compare those scope id.
This patch let sunrpc compares scope id only on link-local addresses.
Signed-off-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

include/linux/sunrpc/clnt.h

@@ -218,7 +218,13 @@ static inline bool __rpc_cmp_addr6(const struct sockaddr *sap1,
 {
 	const struct sockaddr_in6 *sin1 = (const struct sockaddr_in6 *)sap1;
 	const struct sockaddr_in6 *sin2 = (const struct sockaddr_in6 *)sap2;
-	return ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr);
+
+	if (!ipv6_addr_equal(&sin1->sin6_addr, &sin2->sin6_addr))
+		return false;
+	else if (ipv6_addr_type(&sin1->sin6_addr) & IPV6_ADDR_LINKLOCAL)
+		return sin1->sin6_scope_id == sin2->sin6_scope_id;
+
+	return true;
 }
 
 static inline bool __rpc_copy_addr6(struct sockaddr *dst,