Alan Stern noticed that all the wakeup side (and atomic) variants of the
completion APIs should be irq safe, but the newly introduced
completion_done() and try_wait_for_completion() aren't. The use of the
irq unsafe variants in IRQ contexts can cause crashes/hangs.
Fix the problem by making them use spin_lock_irqsave() and
spin_lock_irqrestore().
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: pm list <linux-pm@lists.linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Chinner <david@fromorbit.com>
Cc: Lachlan McIlroy <lachlan@sgi.com>
LKML-Reference: <
200912130007.30541.rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
*/
bool try_wait_for_completion(struct completion *x)
{
*/
bool try_wait_for_completion(struct completion *x)
{
- spin_lock_irq(&x->wait.lock);
+ spin_lock_irqsave(&x->wait.lock, flags);
if (!x->done)
ret = 0;
else
x->done--;
if (!x->done)
ret = 0;
else
x->done--;
- spin_unlock_irq(&x->wait.lock);
+ spin_unlock_irqrestore(&x->wait.lock, flags);
return ret;
}
EXPORT_SYMBOL(try_wait_for_completion);
return ret;
}
EXPORT_SYMBOL(try_wait_for_completion);
*/
bool completion_done(struct completion *x)
{
*/
bool completion_done(struct completion *x)
{
- spin_lock_irq(&x->wait.lock);
+ spin_lock_irqsave(&x->wait.lock, flags);
- spin_unlock_irq(&x->wait.lock);
+ spin_unlock_irqrestore(&x->wait.lock, flags);
return ret;
}
EXPORT_SYMBOL(completion_done);
return ret;
}
EXPORT_SYMBOL(completion_done);