From: Eric Dumazet <edumazet@google.com>
Date: Mon, 6 Jul 2015 12:18:07 +0000 (-0700)
Subject: net_sched: act_gact: read tcfg_ptype once
X-Git-Tag: firefly_0821_release~176^2~1159^2~397^2~2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8f2ae965b7ef4f4ddab6110f06388e270723d694;p=firefly-linux-kernel-4.4.55.git

net_sched: act_gact: read tcfg_ptype once

Third step for gact RCU operation :

Following patch will get rid of spinlock protection,
so we need to read tcfg_ptype once.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index 2f9bec584b3f..e4eb88d3d8dc 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -127,16 +127,16 @@ static int tcf_gact(struct sk_buff *skb, const struct tc_action *a,
 		    struct tcf_result *res)
 {
 	struct tcf_gact *gact = a->priv;
-	int action = TC_ACT_SHOT;
+	int action = gact->tcf_action;
 
 	spin_lock(&gact->tcf_lock);
 #ifdef CONFIG_GACT_PROB
-	if (gact->tcfg_ptype)
-		action = gact_rand[gact->tcfg_ptype](gact);
-	else
-		action = gact->tcf_action;
-#else
-	action = gact->tcf_action;
+	{
+	u32 ptype = READ_ONCE(gact->tcfg_ptype);
+
+	if (ptype)
+		action = gact_rand[ptype](gact);
+	}
 #endif
 	gact->tcf_bstats.bytes += qdisc_pkt_len(skb);
 	gact->tcf_bstats.packets++;