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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/core/dev.c b/net/core/dev.c
index 480be7258f298fd52980846944fb1239f2695b92..2aac4ecac89642e392aa6a98bf5b538fb15da20e 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2829,8 +2829,10 @@ 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;