Commit adac0375 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

driver core: bus: subsys_interface_register/unregister() cleanups 

Convert the subsys_interface_register and subsys_interface_unregister()
functions to use bus_to_subsys() and not use the back-pointer to the
private structure.

This also requires changing the parameters on subsys_dev_iter_init() to
iterate over the list properly.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230208111330.439504-9-gregkh@linuxfoundation.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3465e2e4

drivers/base/bus.c

+29 −16
Original line number Diff line number Diff line
@@ -1023,7 +1023,7 @@ struct subsys_dev_iter { 
/**

 * subsys_dev_iter_init - initialize subsys device iterator

 * @iter: subsys iterator to initialize

 * @subsys: the subsys we wanna iterate over

 * @sp: the subsys private (i.e. bus) we wanna iterate over

 * @start: the device to start iterating from, if any

 * @type: device_type of the devices to iterate over, NULL for all

 *
@@ -1032,14 +1032,14 @@ struct subsys_dev_iter { 
 * otherwise if it is NULL, the iteration starts at the beginning of

 * the list.

 */

static void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,

static void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct subsys_private *sp,

				 struct device *start, const struct device_type *type)

{

	struct klist_node *start_knode = NULL;



	if (start)

		start_knode = &start->p->knode_bus;

	klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);

	klist_iter_init_node(&sp->klist_devices, &iter->ki, start_knode);

	iter->type = type;

}
@@ -1084,26 +1084,31 @@ static void subsys_dev_iter_exit(struct subsys_dev_iter *iter) 


int subsys_interface_register(struct subsys_interface *sif)

{

	struct bus_type *subsys;

	struct subsys_private *sp;

	struct subsys_dev_iter iter;

	struct device *dev;



	if (!sif || !sif->subsys)

		return -ENODEV;



	subsys = bus_get(sif->subsys);

	if (!subsys)

	sp = bus_to_subsys(sif->subsys);

	if (!sp)

		return -EINVAL;



	mutex_lock(&subsys->p->mutex);

	list_add_tail(&sif->node, &subsys->p->interfaces);

	/*

	 * Reference in sp is now incremented and will be dropped when

	 * the interface is removed from the bus

	 */



	mutex_lock(&sp->mutex);

	list_add_tail(&sif->node, &sp->interfaces);

	if (sif->add_dev) {

		subsys_dev_iter_init(&iter, subsys, NULL, NULL);

		subsys_dev_iter_init(&iter, sp, NULL, NULL);

		while ((dev = subsys_dev_iter_next(&iter)))

			sif->add_dev(dev, sif);

		subsys_dev_iter_exit(&iter);

	}

	mutex_unlock(&subsys->p->mutex);

	mutex_unlock(&sp->mutex);



	return 0;

}
@@ -1111,26 +1116,34 @@ EXPORT_SYMBOL_GPL(subsys_interface_register); 


void subsys_interface_unregister(struct subsys_interface *sif)

{

	struct bus_type *subsys;

	struct subsys_private *sp;

	struct subsys_dev_iter iter;

	struct device *dev;



	if (!sif || !sif->subsys)

		return;



	subsys = sif->subsys;

	sp = bus_to_subsys(sif->subsys);

	if (!sp)

		return;



	mutex_lock(&subsys->p->mutex);

	mutex_lock(&sp->mutex);

	list_del_init(&sif->node);

	if (sif->remove_dev) {

		subsys_dev_iter_init(&iter, subsys, NULL, NULL);

		subsys_dev_iter_init(&iter, sp, NULL, NULL);

		while ((dev = subsys_dev_iter_next(&iter)))

			sif->remove_dev(dev, sif);

		subsys_dev_iter_exit(&iter);

	}

	mutex_unlock(&subsys->p->mutex);

	mutex_unlock(&sp->mutex);



	bus_put(subsys);

	/*

	 * Decrement the reference count twice, once for the bus_to_subsys()

	 * call in the start of this function, and the second one from the

	 * reference increment in subsys_interface_register()

	 */

	subsys_put(sp);

	subsys_put(sp);

}

EXPORT_SYMBOL_GPL(subsys_interface_unregister);