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driver core: bus: subsys_interface_register/unregister() cleanups

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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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2023-02-08 12:13:17 +01:00
parent 3465e2e4a2
commit adac037538
1 changed files with 29 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

45
drivers/base/bus.c
View file

@ -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);