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SubjectRe: [patch] clockevents_notify() need to be called with irq's enabled
On Thu, 13 Aug 2009, Suresh Siddha wrote:

> From: Suresh Siddha <suresh.b.siddha@intel.com>
> Subject: clockevents_notify() need to be called with irq's enabled
>
> Currently clockevents_notify() is called with interrupts enabled at some
> places and interrupts disabled at some other places.

The only place I can see which calls clockevents_notify with
interrupts enabled is the hrtimer cpu hotplug code.

I'm a bit wary to enable interrupts all over the place in sensitive
corners like ACPI idle code ...

Why don't we just do the obvious and take clockevents_lock irqsave ?

Thanks,

tglx
---
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index a6dcd67..e43c4b6 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -137,11 +137,12 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
*/
int clockevents_register_notifier(struct notifier_block *nb)
{
+ unsigned long flags;
int ret;

- spin_lock(&clockevents_lock);
+ spin_lock_irqsave(&clockevents_lock, flags);
ret = raw_notifier_chain_register(&clockevents_chain, nb);
- spin_unlock(&clockevents_lock);
+ spin_unlock_irqrestore(&clockevents_lock, flags);

return ret;
}
@@ -181,13 +182,13 @@ void clockevents_register_device(struct clock_event_device *dev)
BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
BUG_ON(!dev->cpumask);

- spin_lock(&clockevents_lock);
+ spin_lock_irqsave(&clockevents_lock, flags);

list_add(&dev->list, &clockevent_devices);
clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
clockevents_notify_released();

- spin_unlock(&clockevents_lock);
+ spin_lock_irqrestore(&clockevents_lock, flags);
}
EXPORT_SYMBOL_GPL(clockevents_register_device);

@@ -235,8 +236,9 @@ void clockevents_exchange_device(struct clock_event_device *old,
void clockevents_notify(unsigned long reason, void *arg)
{
struct list_head *node, *tmp;
+ unsigned long flags;

- spin_lock(&clockevents_lock);
+ spin_lock_irqsave(&clockevents_lock, flags);
clockevents_do_notify(reason, arg);

switch (reason) {
@@ -251,7 +253,7 @@ void clockevents_notify(unsigned long reason, void *arg)
default:
break;
}
- spin_unlock(&clockevents_lock);
+ spin_unlock_irqrestore(&clockevents_lock, flags);
}
EXPORT_SYMBOL_GPL(clockevents_notify);
#endif





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