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hotplug: Reread hotplug_pcp on pin_current_cpu() retry 

When retry happens, it's likely that the task has been migrated to
another cpu (except unplug failed), but it still derefernces the
original hotplug_pcp per cpu data.

Update the pointer to hotplug_pcp in the retry path, so it points to
the current cpu.

Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110728031600.GA338@windriver.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Yong Zhang 2011-07-28 11:16:00 +08:00 committed by Alibek Omarov
parent 1301122193
commit 3a64620113
1 changed files with 3 additions and 1 deletions
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4
kernel/cpu.c
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@ -81,9 +81,11 @@ static DEFINE_PER_CPU(struct hotplug_pcp, hotplug_pcp);
*/
void pin_current_cpu(void)
{
struct hotplug_pcp *hp = &__get_cpu_var(hotplug_pcp);
struct hotplug_pcp *hp;
retry:
hp = &__get_cpu_var(hotplug_pcp);
if (!hp->unplug || hp->refcount || preempt_count() > 1 ||
hp->unplug == current) {
hp->refcount++;