[PATCH v5 32/45] cris/smp: Use get/put_online_cpus_atomic() to prevent CPU offline
From: Srivatsa S. Bhat <hidden>
Date: 2013-01-22 07:44:11
Also in:
linux-arch, linux-arm-kernel, linux-pm, lkml, netdev
Subsystem:
the rest · Maintainer:
Linus Torvalds
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: Mikael Starvik <redacted> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: linux-cris-kernel@axis.com Signed-off-by: Srivatsa S. Bhat <redacted> --- arch/cris/arch-v32/kernel/smp.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/arch/cris/arch-v32/kernel/smp.c b/arch/cris/arch-v32/kernel/smp.c
index 04a16ed..644b358 100644
--- a/arch/cris/arch-v32/kernel/smp.c
+++ b/arch/cris/arch-v32/kernel/smp.c@@ -15,6 +15,7 @@ #include <linux/sched.h> #include <linux/kernel.h> #include <linux/cpumask.h> +#include <linux/cpu.h> #include <linux/interrupt.h> #include <linux/module.h>
@@ -208,9 +209,12 @@ int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle) void smp_send_reschedule(int cpu) { cpumask_t cpu_mask; + + get_online_cpus_atomic(); cpumask_clear(&cpu_mask); cpumask_set_cpu(cpu, &cpu_mask); send_ipi(IPI_SCHEDULE, 0, cpu_mask); + put_online_cpus_atomic(); } /* TLB flushing
@@ -224,6 +228,7 @@ void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned unsigned long flags; cpumask_t cpu_mask; + get_online_cpus_atomic(); spin_lock_irqsave(&tlbstate_lock, flags); cpu_mask = (mm == FLUSH_ALL ? cpu_all_mask : *mm_cpumask(mm)); cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
@@ -232,6 +237,7 @@ void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned flush_addr = addr; send_ipi(IPI_FLUSH_TLB, 1, cpu_mask); spin_unlock_irqrestore(&tlbstate_lock, flags); + put_online_cpus_atomic(); } void flush_tlb_all(void)
@@ -312,6 +318,7 @@ int smp_call_function(void (*func)(void *info), void *info, int wait) struct call_data_struct data; int ret; + get_online_cpus_atomic(); cpumask_setall(&cpu_mask); cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
@@ -325,6 +332,7 @@ int smp_call_function(void (*func)(void *info), void *info, int wait) call_data = &data; ret = send_ipi(IPI_CALL, wait, cpu_mask); spin_unlock(&call_lock); + put_online_cpus_atomic(); return ret; }