From 8587523640441a9ff2564ebc6efeb39497ad6709 Mon Sep 17 00:00:00 2001
From: Tom Herbert <therbert@google.com>
Date: Mon, 31 Jan 2011 16:23:42 -0800
Subject: [PATCH] net: Check rps_flow_table when RPS map length is 1

In get_rps_cpu, add check that the rps_flow_table for the device is
NULL when trying to take fast path when RPS map length is one.
Without this, RFS is effectively disabled if map length is one which
is not correct.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/core/dev.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 93e44dbf6793..4c907895876b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2563,7 +2563,8 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
 
 	map = rcu_dereference(rxqueue->rps_map);
 	if (map) {
-		if (map->len == 1) {
+		if (map->len == 1 &&
+		    !rcu_dereference_raw(rxqueue->rps_flow_table)) {
 			tcpu = map->cpus[0];
 			if (cpu_online(tcpu))
 				cpu = tcpu;
-- 
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