From 5221b82d46f26903cf3161fb7d1fc006170811e0 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 8 Feb 2023 12:13:15 +0100 Subject: driver core: bus: bus_add/probe/remove_device() cleanups Convert the bus_add_device(), bus_probe_device(), and bus_remove_device() functions to use bus_to_subsys() and not use the back-pointer to the private structure. Cc: "Rafael J. Wysocki" Link: https://lore.kernel.org/r/20230208111330.439504-7-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/bus.c | 87 +++++++++++++++++++++++++++++++++--------------------- 1 file changed, 54 insertions(+), 33 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/bus.c b/drivers/base/bus.c index d30a07ff8ab2..a32975028aee 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -466,32 +466,46 @@ EXPORT_SYMBOL_GPL(bus_for_each_drv); */ int bus_add_device(struct device *dev) { - struct bus_type *bus = bus_get(dev->bus); - int error = 0; + struct subsys_private *sp = bus_to_subsys(dev->bus); + int error; - if (bus) { - pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev)); - error = device_add_groups(dev, bus->dev_groups); - if (error) - goto out_put; - error = sysfs_create_link(&bus->p->devices_kset->kobj, - &dev->kobj, dev_name(dev)); - if (error) - goto out_groups; - error = sysfs_create_link(&dev->kobj, - &dev->bus->p->subsys.kobj, "subsystem"); - if (error) - goto out_subsys; - klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices); + if (!sp) { + /* + * This is a normal operation for many devices that do not + * have a bus assigned to them, just say that all went + * well. + */ + return 0; } + + /* + * Reference in sp is now incremented and will be dropped when + * the device is removed from the bus + */ + + pr_debug("bus: '%s': add device %s\n", sp->bus->name, dev_name(dev)); + + error = device_add_groups(dev, sp->bus->dev_groups); + if (error) + goto out_put; + + error = sysfs_create_link(&sp->devices_kset->kobj, &dev->kobj, dev_name(dev)); + if (error) + goto out_groups; + + error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem"); + if (error) + goto out_subsys; + + klist_add_tail(&dev->p->knode_bus, &sp->klist_devices); return 0; out_subsys: - sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev)); + sysfs_remove_link(&sp->devices_kset->kobj, dev_name(dev)); out_groups: - device_remove_groups(dev, bus->dev_groups); + device_remove_groups(dev, sp->bus->dev_groups); out_put: - bus_put(dev->bus); + subsys_put(sp); return error; } @@ -503,20 +517,21 @@ out_put: */ void bus_probe_device(struct device *dev) { - struct bus_type *bus = dev->bus; + struct subsys_private *sp = bus_to_subsys(dev->bus); struct subsys_interface *sif; - if (!bus) + if (!sp) return; - if (bus->p->drivers_autoprobe) + if (sp->drivers_autoprobe) device_initial_probe(dev); - mutex_lock(&bus->p->mutex); - list_for_each_entry(sif, &bus->p->interfaces, node) + mutex_lock(&sp->mutex); + list_for_each_entry(sif, &sp->interfaces, node) if (sif->add_dev) sif->add_dev(dev, sif); - mutex_unlock(&bus->p->mutex); + mutex_unlock(&sp->mutex); + subsys_put(sp); } /** @@ -531,21 +546,20 @@ void bus_probe_device(struct device *dev) */ void bus_remove_device(struct device *dev) { - struct bus_type *bus = dev->bus; + struct subsys_private *sp = bus_to_subsys(dev->bus); struct subsys_interface *sif; - if (!bus) + if (!sp) return; - mutex_lock(&bus->p->mutex); - list_for_each_entry(sif, &bus->p->interfaces, node) + mutex_lock(&sp->mutex); + list_for_each_entry(sif, &sp->interfaces, node) if (sif->remove_dev) sif->remove_dev(dev, sif); - mutex_unlock(&bus->p->mutex); + mutex_unlock(&sp->mutex); sysfs_remove_link(&dev->kobj, "subsystem"); - sysfs_remove_link(&dev->bus->p->devices_kset->kobj, - dev_name(dev)); + sysfs_remove_link(&sp->devices_kset->kobj, dev_name(dev)); device_remove_groups(dev, dev->bus->dev_groups); if (klist_node_attached(&dev->p->knode_bus)) klist_del(&dev->p->knode_bus); @@ -553,7 +567,14 @@ void bus_remove_device(struct device *dev) pr_debug("bus: '%s': remove device %s\n", dev->bus->name, dev_name(dev)); device_release_driver(dev); - bus_put(dev->bus); + + /* + * 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 bus_add_device() + */ + subsys_put(sp); + subsys_put(sp); } static int __must_check add_bind_files(struct device_driver *drv) -- cgit v1.2.3