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authorGautham R Shenoy <ego@in.ibm.com>2007-10-18 23:40:47 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-19 11:53:44 -0700
commitd2b20b11547cefc89d6c81937e81afaf3c62808b (patch)
tree50a6c8e1d86c38fff417907d821eec0e0731e1a5 /lib/percpu_counter.c
parent73e753a50dcac7d6d4fa8b9552203ef544a70d77 (diff)
downloadlinux-linaro-precise-d2b20b11547cefc89d6c81937e81afaf3c62808b.tar.gz
Add irq protection in the percpu-counters cpu-hotplug-callback path
Some of the per-cpu counters and thus their locks are accessed from IRQ contexts. This can cause a deadlock if it interrupts a cpu-offline thread which is transferring a dead-cpu's counts to the global counter. Add appropriate IRQ protection in the cpu-hotplug callback path. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/percpu_counter.c')
-rw-r--r--lib/percpu_counter.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 9659eabffc3..393a0e915c2 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -124,12 +124,13 @@ static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
mutex_lock(&percpu_counters_lock);
list_for_each_entry(fbc, &percpu_counters, list) {
s32 *pcount;
+ unsigned long flags;
- spin_lock(&fbc->lock);
+ spin_lock_irqsave(&fbc->lock, flags);
pcount = per_cpu_ptr(fbc->counters, cpu);
fbc->count += *pcount;
*pcount = 0;
- spin_unlock(&fbc->lock);
+ spin_unlock_irqrestore(&fbc->lock, flags);
}
mutex_unlock(&percpu_counters_lock);
return NOTIFY_OK;