From aae55e4137f49dc33cce78a02a21d916cfd10bb7 Mon Sep 17 00:00:00 2001 From: Priyanka Jain <Priyanka.Jain@freescale.com> Date: Thu, 17 May 2012 09:35:11 +0530 Subject: [PATCH 094/158] net: Remove preemption disabling in netif_rx() 1)enqueue_to_backlog() (called from netif_rx) should be bind to a particluar CPU. This can be achieved by disabling migration. No need to disable preemption 2)Fixes crash "BUG: scheduling while atomic: ksoftirqd" in case of RT. If preemption is disabled, enqueue_to_backog() is called in atomic context. And if backlog exceeds its count, kfree_skb() is called. But in RT, kfree_skb() might gets scheduled out, so it expects non atomic context. -Replace preempt_enable(), preempt_disable() with migrate_enable(), migrate_disable() respectively -Replace get_cpu(), put_cpu() with get_cpu_light(), put_cpu_light() respectively Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Rajan Srivastava <Rajan.Srivastava@freescale.com> Cc: <rostedt@goodmis.orgn> Link: http://lkml.kernel.org/r/1337227511-2271-1-git-send-email-Priyanka.Jain@freescale.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bigeasy: Remove assumption about migrate_disable() from the description.] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- net/core/dev.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Index: linux-5.15.19-rt29/net/core/dev.c =================================================================== @ linux-5.15.19-rt29/net/core/dev.c:4899 @ static int netif_rx_internal(struct sk_b struct rps_dev_flow voidflow, *rflow = &voidflow; int cpu; - preempt_disable(); + migrate_disable(); rcu_read_lock(); cpu = get_rps_cpu(skb->dev, skb, &rflow); @ linux-5.15.19-rt29/net/core/dev.c:4909 @ static int netif_rx_internal(struct sk_b ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail); rcu_read_unlock(); - preempt_enable(); + migrate_enable(); } else #endif { unsigned int qtail; - ret = enqueue_to_backlog(skb, get_cpu(), &qtail); - put_cpu(); + ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail); + put_cpu_light(); } return ret; }