[PATCH 33/45] cris/smp: Use get/put_online_cpus_atomic() to preventCPU offline

From: Srivatsa S. Bhat
Date: Sun Jun 23 2013 - 09:49:09 EST

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: Mikael Starvik <starvik@xxxxxxxx>
Cc: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-cris-kernel@xxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

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

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;

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/