PM / Domains: Queue up power off work only if it is not pending
In theory it is possible that pm_genpd_poweroff() for two different
subdomains of the same parent domain will attempt to queue up the
execution of pm_genpd_poweroff() for the parent twice in a row. This
would lead to unpleasant consequences, so prevent it from happening
by checking if genpd->power_off_work is pending before attempting to
queue it up.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index b6e29ff..c3e4e29 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -213,6 +213,19 @@
}
/**
+ * genpd_queue_power_off_work - Queue up the execution of pm_genpd_poweroff().
+ * @genpd: PM domait to power off.
+ *
+ * Queue up the execution of pm_genpd_poweroff() unless it's already been done
+ * before.
+ */
+static void genpd_queue_power_off_work(struct generic_pm_domain *genpd)
+{
+ if (!work_pending(&genpd->power_off_work))
+ queue_work(pm_wq, &genpd->power_off_work);
+}
+
+/**
* pm_genpd_poweroff - Remove power from a given PM domain.
* @genpd: PM domain to power down.
*
@@ -304,7 +317,7 @@
if (parent) {
genpd_sd_counter_dec(parent);
if (parent->sd_count == 0)
- queue_work(pm_wq, &parent->power_off_work);
+ genpd_queue_power_off_work(parent);
genpd_release_lock(parent);
}