Commit 44cc89f7 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM: runtime: Update device status before letting suppliers suspend 

Because the PM-runtime status of the device is not updated in
__rpm_callback(), attempts to suspend the suppliers of the given
device triggered by rpm_put_suppliers() called by it may fail.

Fix this by making __rpm_callback() update the device's status to
RPM_SUSPENDED before calling rpm_put_suppliers() if the current
status of the device is RPM_SUSPENDING and the callback just invoked
by it has returned 0 (success).

While at it, modify the code in __rpm_callback() to always check
the device's PM-runtime status under its PM lock.

Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/


Fixes: 21d5c57b ("PM / runtime: Use device links")
Reported-by: default avatarElaine Zhang <zhangqing@rock-chips.com>
Diagnosed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: default avatarElaine Zhang <zhangiqng@rock-chips.com>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent fe07bfda

drivers/base/power/runtime.c

+37 −25
Original line number Diff line number Diff line
@@ -325,22 +325,22 @@ static void rpm_put_suppliers(struct device *dev) 
static int __rpm_callback(int (*cb)(struct device *), struct device *dev)

	__releases(&dev->power.lock) __acquires(&dev->power.lock)

{

	int retval, idx;

	bool use_links = dev->power.links_count > 0;

	bool get = false;

	int retval, idx;

	bool put;



	if (dev->power.irq_safe) {

		spin_unlock(&dev->power.lock);

	} else if (!use_links) {

		spin_unlock_irq(&dev->power.lock);

	} else {

		get = dev->power.runtime_status == RPM_RESUMING;



		spin_unlock_irq(&dev->power.lock);



		/*

		 * Resume suppliers if necessary.

		 *

		 * The device's runtime PM status cannot change until this

		 * routine returns, so it is safe to read the status outside of

		 * the lock.

		 */

		if (use_links && dev->power.runtime_status == RPM_RESUMING) {

		/* Resume suppliers if necessary. */

		if (get) {

			idx = device_links_read_lock();



			retval = rpm_get_suppliers(dev);
@@ -355,24 +355,36 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev) 


	if (dev->power.irq_safe) {

		spin_lock(&dev->power.lock);

	} else {

		return retval;

	}



	spin_lock_irq(&dev->power.lock);



	if (!use_links)

		return retval;



	/*

		 * If the device is suspending and the callback has returned

		 * success, drop the usage counters of the suppliers that have

		 * been reference counted on its resume.

	 * If the device is suspending and the callback has returned success,

	 * drop the usage counters of the suppliers that have been reference

	 * counted on its resume.

	 *

		 * Do that if resume fails too.

	 * Do that if the resume fails too.

	 */

		if (use_links

		    && ((dev->power.runtime_status == RPM_SUSPENDING && !retval)

		    || (dev->power.runtime_status == RPM_RESUMING && retval))) {

	put = dev->power.runtime_status == RPM_SUSPENDING && !retval;

	if (put)

		__update_runtime_status(dev, RPM_SUSPENDED);

	else

		put = get && retval;



	if (put) {

		spin_unlock_irq(&dev->power.lock);



		idx = device_links_read_lock();



fail:

		rpm_put_suppliers(dev);



		device_links_read_unlock(idx);

		}



		spin_lock_irq(&dev->power.lock);

	}