netlink: Remove netlink_compare_arg.trailer

herbertx · davem330 · commit 8f2ddaac302a · 2015-03-21T00:16:39.000-04:00
Instead of computing the offset from trailer, this patch computes
netlink_compare_arg_len from the offset of portid and then adds 4
to it.  This allows trailer to be removed.

Reported-by: David Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
@@ -974,10 +974,11 @@ struct netlink_compare_arg
 {
 	possible_net_t pnet;
 	u32 portid;
-	char trailer[];
 };
 
-#define netlink_compare_arg_len offsetof(struct netlink_compare_arg, trailer)
+/* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
+#define netlink_compare_arg_len \
+	(offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
 
 static inline int netlink_compare(struct rhashtable_compare_arg *arg,
 				  const void *ptr)
