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authorJohn Stultz <john.stultz@linaro.org>2012-09-06 23:19:06 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2012-09-06 23:19:06 +0200
commit4955070974ecfa0b1ae9d2506f529460fd3a4b0b (patch)
tree7eaf09c1756fa1bf2534998a60b9543cc411d79d
parent5834ec3aea8a84b70efeb52ee91a8f8b1042cd2a (diff)
downloadvexpress-lsk-4955070974ecfa0b1ae9d2506f529460fd3a4b0b.tar.gz
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>
-rw-r--r--drivers/base/power/wakeup.c17
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 8a0a9ca6ad6..e6ee5e80e54 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;
}