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| author | John Stultz <john.stultz@linaro.org> | 2012-09-06 23:19:06 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rjw@sisk.pl> | 2012-09-06 23:19:06 +0200 |
| commit | 4955070974ecfa0b1ae9d2506f529460fd3a4b0b (patch) | |
| tree | 7eaf09c1756fa1bf2534998a60b9543cc411d79d /drivers/base/power/wakeup.c | |
| parent | 5834ec3aea8a84b70efeb52ee91a8f8b1042cd2a (diff) | |
| download | lwn-4955070974ecfa0b1ae9d2506f529460fd3a4b0b.tar.gz lwn-4955070974ecfa0b1ae9d2506f529460fd3a4b0b.zip | |
PM / wakeup: Use irqsave/irqrestore for events_lock
Jon Medhurst (Tixy) recently noticed a problem with the
events_lock usage. One of the Android patches that uses
wakeup_sources calls wakeup_source_add() with irqs disabled.
However, the event_lock usage in wakeup_source_add() uses
spin_lock_irq()/spin_unlock_irq(), which reenables interrupts.
This results in lockdep warnings.
The fix is to use spin_lock_irqsave()/spin_lock_irqrestore()
instead for the events_lock.
References: https://bugs.launchpad.net/linaro-landing-team-arm/+bug/1037565
Reported-and-debugged-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers/base/power/wakeup.c')
| -rw-r--r-- | drivers/base/power/wakeup.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index 8a0a9ca6ad65..e6ee5e80e546 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -127,6 +127,8 @@ EXPORT_SYMBOL_GPL(wakeup_source_destroy); */ void wakeup_source_add(struct wakeup_source *ws) { + unsigned long flags; + if (WARN_ON(!ws)) return; @@ -135,9 +137,9 @@ void wakeup_source_add(struct wakeup_source *ws) ws->active = false; ws->last_time = ktime_get(); - spin_lock_irq(&events_lock); + spin_lock_irqsave(&events_lock, flags); list_add_rcu(&ws->entry, &wakeup_sources); - spin_unlock_irq(&events_lock); + spin_unlock_irqrestore(&events_lock, flags); } EXPORT_SYMBOL_GPL(wakeup_source_add); @@ -147,12 +149,14 @@ EXPORT_SYMBOL_GPL(wakeup_source_add); */ void wakeup_source_remove(struct wakeup_source *ws) { + unsigned long flags; + if (WARN_ON(!ws)) return; - spin_lock_irq(&events_lock); + spin_lock_irqsave(&events_lock, flags); list_del_rcu(&ws->entry); - spin_unlock_irq(&events_lock); + spin_unlock_irqrestore(&events_lock, flags); synchronize_rcu(); } EXPORT_SYMBOL_GPL(wakeup_source_remove); @@ -752,15 +756,16 @@ bool pm_get_wakeup_count(unsigned int *count, bool block) bool pm_save_wakeup_count(unsigned int count) { unsigned int cnt, inpr; + unsigned long flags; events_check_enabled = false; - spin_lock_irq(&events_lock); + spin_lock_irqsave(&events_lock, flags); split_counters(&cnt, &inpr); if (cnt == count && inpr == 0) { saved_count = count; events_check_enabled = true; } - spin_unlock_irq(&events_lock); + spin_unlock_irqrestore(&events_lock, flags); return events_check_enabled; } |