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Commit 3c07cbc4 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM / Domains: Do not take parent locks to modify subdomain counters 



After the subdomain counter in struct generic_pm_domain has been
changed into an atomic_t field, it is possible to modify
pm_genpd_poweron() and pm_genpd_poweroff() so that they don't take
the parents locks.  This requires pm_genpd_poweron() to increment
the parent's subdomain counter before calling itself recursively
for the parent and to decrement it if an error is to be returned.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent c4bb3160

drivers/base/power/domain.c

+31 −39
Original line number Diff line number Diff line
@@ -93,12 +93,7 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd) 
	int ret = 0;



 start:

	if (parent) {

		genpd_acquire_lock(parent);

		mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);

	} else {

	mutex_lock(&genpd->lock);

	}



	if (genpd->status == GPD_STATE_ACTIVE

	    || (genpd->prepared_count > 0 && genpd->suspend_power_off))
@@ -109,31 +104,33 @@ int pm_genpd_poweron(struct generic_pm_domain *genpd) 
		goto out;

	}



	if (parent && parent->status != GPD_STATE_ACTIVE) {

	if (parent) {

		genpd_sd_counter_inc(parent);



		mutex_unlock(&genpd->lock);

		genpd_release_lock(parent);



		ret = pm_genpd_poweron(parent);

		if (ret)

		if (ret) {

			genpd_sd_counter_dec(parent);

			return ret;

		}



		parent = NULL;

		goto start;

	}



	if (genpd->power_on) {

	if (genpd->power_on)

		ret = genpd->power_on(genpd);

		if (ret)

			goto out;

	}



	if (ret) {

		if (genpd->parent)

			genpd_sd_counter_dec(genpd->parent);

	} else {

		genpd_set_active(genpd);

	if (parent)

		genpd_sd_counter_inc(parent);

	}



 out:

	mutex_unlock(&genpd->lock);

	if (parent)

		genpd_release_lock(parent);



	return ret;

}
@@ -293,7 +290,8 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd) 
	genpd->poweroff_task = current;



	list_for_each_entry_reverse(dle, &genpd->dev_list, node) {

		ret = __pm_genpd_save_device(dle, genpd);

		ret = atomic_read(&genpd->sd_count) == 0 ?

			__pm_genpd_save_device(dle, genpd) : -EBUSY;

		if (ret) {

			genpd_set_active(genpd);

			goto out;
@@ -308,39 +306,33 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd) 
		}

	}



	parent = genpd->parent;

	if (parent) {

		mutex_unlock(&genpd->lock);



		genpd_acquire_lock(parent);

		mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);



		if (genpd_abort_poweroff(genpd)) {

			genpd_release_lock(parent);

	if (genpd->power_off) {

		if (atomic_read(&genpd->sd_count) > 0) {

			ret = -EBUSY;

			goto out;

		}

	}



	if (genpd->power_off) {

		/*

		 * If sd_count > 0 at this point, one of the children hasn't

		 * managed to call pm_genpd_poweron() for the parent yet after

		 * incrementing it.  In that case pm_genpd_poweron() will wait

		 * for us to drop the lock, so we can call .power_off() and let

		 * the pm_genpd_poweron() restore power for us (this shouldn't

		 * happen very often).

		 */

		ret = genpd->power_off(genpd);

		if (ret == -EBUSY) {

			genpd_set_active(genpd);

			if (parent)

				genpd_release_lock(parent);



			goto out;

		}

	}



	genpd->status = GPD_STATE_POWER_OFF;



	if (parent) {

		if (genpd_sd_counter_dec(parent))

	parent = genpd->parent;

	if (parent && genpd_sd_counter_dec(parent))

		genpd_queue_power_off_work(parent);



		genpd_release_lock(parent);

	}



 out:

	genpd->poweroff_task = NULL;

	wake_up_all(&genpd->status_wait_queue);