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: Hirokazu Takata <takata@xxxxxxxxxxxxxx> Cc: linux-m32r@xxxxxxxxxxxxxxxxx Cc: linux-m32r-ja@xxxxxxxxxxxxxxxxx Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx> --- arch/m32r/kernel/smp.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/m32r/kernel/smp.c b/arch/m32r/kernel/smp.c index ce7aea3..0dad4d7 100644 --- a/arch/m32r/kernel/smp.c +++ b/arch/m32r/kernel/smp.c @@ -151,7 +151,7 @@ void smp_flush_cache_all(void) cpumask_t cpumask; unsigned long *mask; - preempt_disable(); + get_online_cpus_atomic(); cpumask_copy(&cpumask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &cpumask); spin_lock(&flushcache_lock); @@ -162,7 +162,7 @@ void smp_flush_cache_all(void) while (flushcache_cpumask) mb(); spin_unlock(&flushcache_lock); - preempt_enable(); + put_online_cpus_atomic(); } void smp_flush_cache_all_interrupt(void) @@ -250,7 +250,7 @@ void smp_flush_tlb_mm(struct mm_struct *mm) unsigned long *mmc; unsigned long flags; - preempt_disable(); + get_online_cpus_atomic(); cpu_id = smp_processor_id(); mmc = &mm->context[cpu_id]; cpumask_copy(&cpu_mask, mm_cpumask(mm)); @@ -268,7 +268,7 @@ void smp_flush_tlb_mm(struct mm_struct *mm) if (!cpumask_empty(&cpu_mask)) flush_tlb_others(cpu_mask, mm, NULL, FLUSH_ALL); - preempt_enable(); + put_online_cpus_atomic(); } /*==========================================================================* @@ -715,10 +715,12 @@ static void send_IPI_allbutself(int ipi_num, int try) { cpumask_t cpumask; + get_online_cpus_atomic(); cpumask_copy(&cpumask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &cpumask); send_IPI_mask(&cpumask, ipi_num, try); + put_online_cpus_atomic(); } /*==========================================================================* @@ -750,6 +752,7 @@ static void send_IPI_mask(const struct cpumask *cpumask, int ipi_num, int try) if (num_cpus <= 1) /* NO MP */ return; + get_online_cpus_atomic(); cpumask_and(&tmp, cpumask, cpu_online_mask); BUG_ON(!cpumask_equal(cpumask, &tmp)); @@ -760,6 +763,7 @@ static void send_IPI_mask(const struct cpumask *cpumask, int ipi_num, int try) } send_IPI_mask_phys(&physid_mask, ipi_num, try); + put_online_cpus_atomic(); } /*==========================================================================* -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html