[v3,33/45] cris/smp: Use get/put_online_cpus_atomic() to prevent CPU offline

Message ID 20130627195823.29830.57756.stgit@srivatsabhat.in.ibm.com
State Not Applicable, archived
Delegated to: David Miller
Headers show

Commit Message

Srivatsa S. Bhat June 27, 2013, 7:58 p.m.
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.

Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-cris-kernel@axis.com
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>

 arch/cris/arch-v32/kernel/smp.c |    5 +++++
 1 file changed, 5 insertions(+)

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diff --git a/arch/cris/arch-v32/kernel/smp.c b/arch/cris/arch-v32/kernel/smp.c
index cdd1202..b2d4612 100644
--- a/arch/cris/arch-v32/kernel/smp.c
+++ b/arch/cris/arch-v32/kernel/smp.c
@@ -13,6 +13,7 @@ 
 #include <linux/init.h>
 #include <linux/timex.h>
 #include <linux/sched.h>
+#include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/cpumask.h>
 #include <linux/interrupt.h>
@@ -222,6 +223,7 @@  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);
@@ -230,6 +232,7 @@  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)
@@ -319,10 +322,12 @@  int smp_call_function(void (*func)(void *info), void *info, int wait)
 	data.info = info;
 	data.wait = wait;
+	get_online_cpus_atomic();
 	call_data = &data;
 	ret = send_ipi(IPI_CALL, wait, cpu_mask);
+	put_online_cpus_atomic();
 	return ret;