[PATCH v2 37/45] m32r: Use get/put_online_cpus_atomic() to prevent CPU offline

[Srivatsa S. Bhat]

Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption 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 <tak...@linux-m32r.org>
Cc: linux-m...@ml.linux-m32r.org
Cc: linux-m32r...@ml.linux-m32r.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com>
---

 arch/m32r/kernel/smp.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/m32r/kernel/smp.c b/arch/m32r/kernel/smp.c
index ce7aea3..ffafdba 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)
@@ -197,12 +197,12 @@ void smp_flush_tlb_all(void)
 {
        unsigned long flags;
 
-       preempt_disable();
+       get_online_cpus_atomic();
        local_irq_save(flags);
        __flush_tlb_all();
        local_irq_restore(flags);
        smp_call_function(flush_tlb_all_ipi, NULL, 1);
-       preempt_enable();
+       put_online_cpus_atomic();
 }
 
 /*==========================================================================*
@@ -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();
 }
 
 /*==========================================================================*
@@ -320,7 +320,7 @@ void smp_flush_tlb_page(struct vm_area_struct *vma, 
unsigned long va)
        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));
@@ -341,7 +341,7 @@ void smp_flush_tlb_page(struct vm_area_struct *vma, 
unsigned long va)
        if (!cpumask_empty(&cpu_mask))
                flush_tlb_others(cpu_mask, mm, vma, va);
 
-       preempt_enable();
+       put_online_cpus_atomic();
 }
 
 /*==========================================================================*

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