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Commit 5db25c9e authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Greg Kroah-Hartman
Browse files

driver core: Do not resume suppliers under device_links_write_lock() 



It is incorrect to call pm_runtime_get_sync() under
device_links_write_lock(), because it may end up trying to take
device_links_read_lock() while resuming the target device and that
will deadlock in the non-SRCU case, so avoid that by resuming the
supplier device in device_link_add() before calling
device_links_write_lock().

Fixes: 21d5c57b ("PM / runtime: Use device links")
Fixes: baa8809f ("PM / runtime: Optimize the use of device links")
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f265df55

drivers/base/core.c

+14 −6
Original line number Diff line number Diff line
@@ -201,12 +201,21 @@ struct device_link *device_link_add(struct device *consumer, 
				    struct device *supplier, u32 flags)

{

	struct device_link *link;

	bool rpm_put_supplier = false;



	if (!consumer || !supplier ||

	    (flags & DL_FLAG_STATELESS &&

	     flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER)))

		return NULL;



	if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {

		if (pm_runtime_get_sync(supplier) < 0) {

			pm_runtime_put_noidle(supplier);

			return NULL;

		}

		rpm_put_supplier = true;

	}



	device_links_write_lock();

	device_pm_lock();
@@ -250,13 +259,8 @@ struct device_link *device_link_add(struct device *consumer, 


	if (flags & DL_FLAG_PM_RUNTIME) {

		if (flags & DL_FLAG_RPM_ACTIVE) {

			if (pm_runtime_get_sync(supplier) < 0) {

				pm_runtime_put_noidle(supplier);

				kfree(link);

				link = NULL;

				goto out;

			}

			link->rpm_active = true;

			rpm_put_supplier = false;

		}

		pm_runtime_new_link(consumer);

		/*
@@ -328,6 +332,10 @@ struct device_link *device_link_add(struct device *consumer, 
 out:

	device_pm_unlock();

	device_links_write_unlock();



	if (rpm_put_supplier)

		pm_runtime_put(supplier);



	return link;

}

EXPORT_SYMBOL_GPL(device_link_add);