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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2010-04-15 00:14:07 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-04-15 00:14:07 -0700 |
| commit | b0e28f1effd1d840b36e961edc1def81e01b1ca1 (patch) | |
| tree | 41e4299d3039dda9e3977c1a8625d09554e6fe4e /net/core/dev.c | |
| parent | Merge branch 'vhost' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost (diff) | |
| download | linux-dev-b0e28f1effd1d840b36e961edc1def81e01b1ca1.tar.xz linux-dev-b0e28f1effd1d840b36e961edc1def81e01b1ca1.zip | |
net: netif_rx() must disable preemption
Eric Paris reported netif_rx() is calling smp_processor_id() from
preemptible context, in particular when caller is
ip_dev_loopback_xmit().
RPS commit added this smp_processor_id() call, this patch makes sure
preemption is disabled. rps_get_cpus() wants rcu_read_lock() anyway, we
can dot it a bit earlier.
Reported-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 876b1112d5ba..e8041eb76ac1 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2206,6 +2206,7 @@ DEFINE_PER_CPU(struct netif_rx_stats, netdev_rx_stat) = { 0, }; /* * get_rps_cpu is called from netif_receive_skb and returns the target * CPU from the RPS map of the receiving queue for a given skb. + * rcu_read_lock must be held on entry. */ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb) { @@ -2217,8 +2218,6 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb) u8 ip_proto; u32 addr1, addr2, ports, ihl; - rcu_read_lock(); - if (skb_rx_queue_recorded(skb)) { u16 index = skb_get_rx_queue(skb); if (unlikely(index >= dev->num_rx_queues)) { @@ -2296,7 +2295,6 @@ got_hash: } done: - rcu_read_unlock(); return cpu; } @@ -2392,7 +2390,7 @@ enqueue: int netif_rx(struct sk_buff *skb) { - int cpu; + int ret; /* if netpoll wants it, pretend we never saw it */ if (netpoll_rx(skb)) @@ -2402,14 +2400,21 @@ int netif_rx(struct sk_buff *skb) net_timestamp(skb); #ifdef CONFIG_RPS - cpu = get_rps_cpu(skb->dev, skb); - if (cpu < 0) - cpu = smp_processor_id(); + { + int cpu; + + rcu_read_lock(); + cpu = get_rps_cpu(skb->dev, skb); + if (cpu < 0) + cpu = smp_processor_id(); + ret = enqueue_to_backlog(skb, cpu); + rcu_read_unlock(); + } #else - cpu = smp_processor_id(); + ret = enqueue_to_backlog(skb, get_cpu()); + put_cpu(); #endif - - return enqueue_to_backlog(skb, cpu); + return ret; } EXPORT_SYMBOL(netif_rx); |