act_mirred: cleanup

1. don't let go back using goto.
2. don't call skb_act_clone() until it is necessary.
3. one exit of the critical context.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 33 insertions, 26 deletions

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index b9aaab4e0354..b812c20b66c6 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -148,47 +148,39 @@ static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 {
         struct tcf_mirred *m = a->priv;
         struct net_device *dev;
-        struct sk_buff *skb2 = NULL;
-        u32 at = G_TC_AT(skb->tc_verd);
+        struct sk_buff *skb2;
+        u32 at;
+        int retval, err = 1;
 
         spin_lock(&m->tcf_lock);
-
-        dev = m->tcfm_dev;
         m->tcf_tm.lastuse = jiffies;
+        if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
+            m->tcfm_eaction != TCA_EGRESS_REDIR) {
+                if (net_ratelimit())
+                        printk("tcf_mirred unknown action %d\n",
+                               m->tcfm_eaction);
+                goto out;
+        }
 
-        if (!(dev->flags&IFF_UP) ) {
+        dev = m->tcfm_dev;
+        if (!(dev->flags & IFF_UP)) {
                 if (net_ratelimit())
                         printk("mirred to Houston: device %s is gone!\n",
                                dev->name);
-bad_mirred:
-                if (skb2 != NULL)
-                        kfree_skb(skb2);
-                m->tcf_qstats.overlimits++;
-                m->tcf_bstats.bytes += qdisc_pkt_len(skb);
-                m->tcf_bstats.packets++;
-                spin_unlock(&m->tcf_lock);
-                /* should we be asking for packet to be dropped?
-                 * may make sense for redirect case only
-                */
-                return TC_ACT_SHOT;
+                goto out;
         }
 
         skb2 = skb_act_clone(skb, GFP_ATOMIC);
         if (skb2 == NULL)
-                goto bad_mirred;
-        if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
-            m->tcfm_eaction != TCA_EGRESS_REDIR) {
-                if (net_ratelimit())
-                        printk("tcf_mirred unknown action %d\n",
-                               m->tcfm_eaction);
-                goto bad_mirred;
-        }
+                goto out;
 
         m->tcf_bstats.bytes += qdisc_pkt_len(skb2);
         m->tcf_bstats.packets++;
-        if (!(at & AT_EGRESS))
+        at = G_TC_AT(skb->tc_verd);
+        if (!(at & AT_EGRESS)) {
                 if (m->tcfm_ok_push)
                         skb_push(skb2, skb2->dev->hard_header_len);
+        }
 
         /* mirror is always swallowed */
         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
@@ -197,8 +189,23 @@ bad_mirred:
         skb2->dev = dev;
         skb2->iif = skb->dev->ifindex;
         dev_queue_xmit(skb2);
+        err = 0;
+
+out:
+        if (err) {
+                m->tcf_qstats.overlimits++;
+                m->tcf_bstats.bytes += qdisc_pkt_len(skb);
+                m->tcf_bstats.packets++;
+                /* should we be asking for packet to be dropped?
+                 * may make sense for redirect case only
+                 */
+                retval = TC_ACT_SHOT;
+        } else {
+                retval = m->tcf_action;
+        }
         spin_unlock(&m->tcf_lock);
-        return m->tcf_action;
+
+        return retval;
 }
 
 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)