net-rps: Fix brokeness causing OOO packets

[ Upstream commit baefa31db2f2b13a05d1b81bdf2d20d487f58b0a ]

In commit c445477d74ab3779 which adds aRFS to the kernel, the CPU
selected for RFS is not set correctly when CPU is changing.
This is causing OOO packets and probably other issues.

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index aed87a401458db1cc2655a7c03be0009a7b7718f..1dce5b5f614b74d70107142d7af13749c6650d9e 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2793,8 +2793,10 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
                if (unlikely(tcpu != next_cpu) &&
                    (tcpu == RPS_NO_CPU || !cpu_online(tcpu) ||
                     ((int)(per_cpu(softnet_data, tcpu).input_queue_head -
-                     rflow->last_qtail)) >= 0))
+                     rflow->last_qtail)) >= 0)) {
+                       tcpu = next_cpu;
                        rflow = set_rps_cpu(dev, skb, rflow, next_cpu);
+               }
 
                if (tcpu != RPS_NO_CPU && cpu_online(tcpu)) {
                        *rflowp = rflow;