netdev - [PATCH v3 net-next 5/7] net_sched: act_gact: read tcfg

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Date:	Mon,  6 Jul 2015 05:18:07 -0700
From:	Eric Dumazet <edumazet@...gle.com>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>,
	Alexei Starovoitov <ast@...mgrid.com>,
	Jamal Hadi Salim <jhs@...atatu.com>,
	John Fastabend <john.fastabend@...il.com>,
	Eric Dumazet <edumazet@...gle.com>,
	Eric Dumazet <edumazet@...il.com>
Subject: [PATCH v3 net-next 5/7] 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@...gle.com>
Cc: Alexei Starovoitov <ast@...mgrid.com>
Acked-by: Jamal Hadi Salim <jhs@...atatu.com>
Acked-by: John Fastabend <john.fastabend@...il.com>
---
 net/sched/act_gact.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

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++;
-- 
2.4.3.573.g4eafbef

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