@@ -4796,7 +4796,6 @@ static int netif_rx_internal(struct sk_buff *skb)
struct rps_dev_flow voidflow, *rflow = &voidflow;
int cpu;
- preempt_disable();
rcu_read_lock();
cpu = get_rps_cpu(skb->dev, skb, &rflow);
@@ -4806,14 +4805,12 @@ static int netif_rx_internal(struct sk_buff *skb)
ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
rcu_read_unlock();
- preempt_enable();
} else
#endif
{
unsigned int qtail;
- ret = enqueue_to_backlog(skb, get_cpu(), &qtail);
- put_cpu();
+ ret = enqueue_to_backlog(skb, smp_processor_id(), &qtail);
}
return ret;
}
The preempt_disable() () section was introduced in commit cece1945bffcf ("net: disable preemption before call smp_processor_id()") and adds it in case this function is invoked from preemtible context and because get_cpu() later on as been added. The get_cpu() usage was added in commit b0e28f1effd1d ("net: netif_rx() must disable preemption") because ip_dev_loopback_xmit() invoked netif_rx() with enabled preemption causing a warning in smp_processor_id(). The function netif_rx() should only be invoked from an interrupt context which implies disabled preemption. The commit e30b38c298b55 ("ip: Fix ip_dev_loopback_xmit()") was addressing this and replaced netif_rx() with in netif_rx_ni() in ip_dev_loopback_xmit(). Based on the discussion on the list, the former patch (b0e28f1effd1d) should not have been applied only the latter (e30b38c298b55). Remove get_cpu() and preempt_disable() since the function is supposed to be invoked from context with stable per-CPU pointers. Bottom halves have to be disabled at this point because the function may raise softirqs which need to be processed. Link: https://lkml.kernel.org/r/20100415.013347.98375530.davem@davemloft.net Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> --- net/core/dev.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)