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-rw-r--r--drivers/power/power_supply_core.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index bcff7fdf733a..26518c8218ea 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -78,7 +78,14 @@ static void power_supply_changed_work(struct work_struct *work)
dev_dbg(psy->dev, "%s\n", __func__);
spin_lock_irqsave(&psy->changed_lock, flags);
- if (psy->changed) {
+ /*
+ * Check 'changed' here to avoid issues due to race between
+ * power_supply_changed() and this routine. In worst case
+ * power_supply_changed() can be called again just before we take above
+ * lock. During the first call of this routine we will mark 'changed' as
+ * false and it will stay false for the next call as well.
+ */
+ if (likely(psy->changed)) {
psy->changed = false;
spin_unlock_irqrestore(&psy->changed_lock, flags);
class_for_each_device(power_supply_class, NULL, psy,
@@ -89,12 +96,13 @@ static void power_supply_changed_work(struct work_struct *work)
kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
spin_lock_irqsave(&psy->changed_lock, flags);
}
+
/*
- * Dependent power supplies (e.g. battery) may have changed state
- * as a result of this event, so poll again and hold the
- * wakeup_source until all events are processed.
+ * Hold the wakeup_source until all events are processed.
+ * power_supply_changed() might have called again and have set 'changed'
+ * to true.
*/
- if (!psy->changed)
+ if (likely(!psy->changed))
pm_relax(psy->dev);
spin_unlock_irqrestore(&psy->changed_lock, flags);
}