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Date: Tue, 22 Jan 2013 13:08:21 +0530 From: "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com> To: tglx@...utronix.de, peterz@...radead.org, tj@...nel.org, oleg@...hat.com, paulmck@...ux.vnet.ibm.com, rusty@...tcorp.com.au, mingo@...nel.org, akpm@...ux-foundation.org, namhyung@...nel.org Cc: rostedt@...dmis.org, wangyun@...ux.vnet.ibm.com, xiaoguangrong@...ux.vnet.ibm.com, rjw@...k.pl, sbw@....edu, fweisbec@...il.com, linux@....linux.org.uk, nikunj@...ux.vnet.ibm.com, srivatsa.bhat@...ux.vnet.ibm.com, linux-pm@...r.kernel.org, linux-arch@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org, netdev@...r.kernel.org, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH v5 19/45] net: Use get/put_online_cpus_atomic() to prevent CPU offline Once stop_machine() is gone from the CPU offline path, we won't be able to depend on preempt_disable() or local_irq_disable() to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: "David S. Miller" <davem@...emloft.net> Cc: Eric Dumazet <edumazet@...gle.com> Cc: netdev@...r.kernel.org Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com> --- net/core/dev.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index f64e439..5421f96 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3089,7 +3089,7 @@ int netif_rx(struct sk_buff *skb) struct rps_dev_flow voidflow, *rflow = &voidflow; int cpu; - preempt_disable(); + get_online_cpus_atomic(); rcu_read_lock(); cpu = get_rps_cpu(skb->dev, skb, &rflow); @@ -3099,7 +3099,7 @@ int netif_rx(struct sk_buff *skb) ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail); rcu_read_unlock(); - preempt_enable(); + put_online_cpus_atomic(); } else #endif { @@ -3498,6 +3498,7 @@ int netif_receive_skb(struct sk_buff *skb) struct rps_dev_flow voidflow, *rflow = &voidflow; int cpu, ret; + get_online_cpus_atomic(); rcu_read_lock(); cpu = get_rps_cpu(skb->dev, skb, &rflow); @@ -3505,9 +3506,11 @@ int netif_receive_skb(struct sk_buff *skb) if (cpu >= 0) { ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail); rcu_read_unlock(); + put_online_cpus_atomic(); return ret; } rcu_read_unlock(); + put_online_cpus_atomic(); } #endif return __netif_receive_skb(skb); @@ -3887,6 +3890,7 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd) local_irq_enable(); /* Send pending IPI's to kick RPS processing on remote cpus. */ + get_online_cpus_atomic(); while (remsd) { struct softnet_data *next = remsd->rps_ipi_next; @@ -3895,6 +3899,7 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd) &remsd->csd, 0); remsd = next; } + put_online_cpus_atomic(); } else #endif local_irq_enable(); -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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