net_sched: optimize tcf_match_indev()

tcf_match_indev() is called in fast path, it is not wise to
search for a netdev by ifindex and then compare by its name,
just compare the ifindex.

Also, dev->name could be changed by user-space, therefore
the match would be always fail, but dev->ifindex could
be consistent.

BTW, this will also save some bytes from the core struct of u32.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index d605285..ca662aa 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -41,7 +41,7 @@
 	u32			id;
 	struct tcf_result	res;
 #ifdef CONFIG_NET_CLS_IND
-	char			indev[IFNAMSIZ];
+	int			ifindex;
 #endif /* CONFIG_NET_CLS_IND */
 	struct tcf_exts		exts;
 };
@@ -86,7 +86,7 @@
 			if (f->id == id) {
 				*res = f->res;
 #ifdef CONFIG_NET_CLS_IND
-				if (!tcf_match_indev(skb, f->indev))
+				if (!tcf_match_indev(skb, f->ifindex))
 					continue;
 #endif /* CONFIG_NET_CLS_IND */
 				r = tcf_exts_exec(skb, &f->exts, res);
@@ -207,9 +207,11 @@
 
 #ifdef CONFIG_NET_CLS_IND
 	if (tb[TCA_FW_INDEV]) {
-		err = tcf_change_indev(tp, f->indev, tb[TCA_FW_INDEV]);
-		if (err < 0)
+		int ret;
+		ret = tcf_change_indev(net, tb[TCA_FW_INDEV]);
+		if (ret < 0)
 			goto errout;
+		f->ifindex = ret;
 	}
 #endif /* CONFIG_NET_CLS_IND */
 
@@ -348,9 +350,12 @@
 	    nla_put_u32(skb, TCA_FW_CLASSID, f->res.classid))
 		goto nla_put_failure;
 #ifdef CONFIG_NET_CLS_IND
-	if (strlen(f->indev) &&
-	    nla_put_string(skb, TCA_FW_INDEV, f->indev))
-		goto nla_put_failure;
+	if (f->ifindex) {
+		struct net_device *dev;
+		dev = __dev_get_by_index(net, f->ifindex);
+		if (dev && nla_put_string(skb, TCA_FW_INDEV, dev->name))
+			goto nla_put_failure;
+	}
 #endif /* CONFIG_NET_CLS_IND */
 	if (head->mask != 0xFFFFFFFF &&
 	    nla_put_u32(skb, TCA_FW_MASK, head->mask))