diff options
Diffstat (limited to 'drivers/base/bus.c')
| -rw-r--r-- | drivers/base/bus.c | 803 |
1 files changed, 498 insertions, 305 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c index e06a57936cc9..9eb7771706f0 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -6,9 +6,11 @@ * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2007 Novell Inc. + * Copyright (c) 2023 Greg Kroah-Hartman <gregkh@linuxfoundation.org> */ #include <linux/async.h> +#include <linux/device/bus.h> #include <linux/device.h> #include <linux/module.h> #include <linux/errno.h> @@ -23,6 +25,9 @@ /* /sys/devices/system */ static struct kset *system_kset; +/* /sys/bus */ +static struct kset *bus_kset; + #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) /* @@ -38,19 +43,63 @@ static struct kset *system_kset; static int __must_check bus_rescan_devices_helper(struct device *dev, void *data); -static struct bus_type *bus_get(struct bus_type *bus) +/** + * bus_to_subsys - Turn a struct bus_type into a struct subsys_private + * + * @bus: pointer to the struct bus_type to look up + * + * The driver core internals needs to work on the subsys_private structure, not + * the external struct bus_type pointer. This function walks the list of + * registered busses in the system and finds the matching one and returns the + * internal struct subsys_private that relates to that bus. + * + * Note, the reference count of the return value is INCREMENTED if it is not + * NULL. A call to subsys_put() must be done when finished with the pointer in + * order for it to be properly freed. + */ +struct subsys_private *bus_to_subsys(const struct bus_type *bus) { - if (bus) { - kset_get(&bus->p->subsys); - return bus; + struct subsys_private *sp = NULL; + struct kobject *kobj; + + if (!bus || !bus_kset) + return NULL; + + spin_lock(&bus_kset->list_lock); + + if (list_empty(&bus_kset->list)) + goto done; + + list_for_each_entry(kobj, &bus_kset->list, entry) { + struct kset *kset = container_of(kobj, struct kset, kobj); + + sp = container_of_const(kset, struct subsys_private, subsys); + if (sp->bus == bus) + goto done; } + sp = NULL; +done: + sp = subsys_get(sp); + spin_unlock(&bus_kset->list_lock); + return sp; +} + +static const struct bus_type *bus_get(const struct bus_type *bus) +{ + struct subsys_private *sp = bus_to_subsys(bus); + + if (sp) + return bus; return NULL; } -static void bus_put(struct bus_type *bus) +static void bus_put(const struct bus_type *bus) { - if (bus) - kset_put(&bus->p->subsys); + struct subsys_private *sp = bus_to_subsys(bus); + + /* two puts are required as the call to bus_to_subsys incremented it again */ + subsys_put(sp); + subsys_put(sp); } static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr, @@ -90,7 +139,7 @@ static void driver_release(struct kobject *kobj) kfree(drv_priv); } -static struct kobj_type driver_ktype = { +static const struct kobj_type driver_ktype = { .sysfs_ops = &driver_sysfs_ops, .release = driver_release, }; @@ -103,7 +152,8 @@ static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr, { struct bus_attribute *bus_attr = to_bus_attr(attr); struct subsys_private *subsys_priv = to_subsys_private(kobj); - ssize_t ret = 0; + /* return -EIO for reading a bus attribute without show() */ + ssize_t ret = -EIO; if (bus_attr->show) ret = bus_attr->show(subsys_priv->bus, buf); @@ -115,7 +165,8 @@ static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr, { struct bus_attribute *bus_attr = to_bus_attr(attr); struct subsys_private *subsys_priv = to_subsys_private(kobj); - ssize_t ret = 0; + /* return -EIO for writing a bus attribute without store() */ + ssize_t ret = -EIO; if (bus_attr->store) ret = bus_attr->store(subsys_priv->bus, buf, count); @@ -127,44 +178,49 @@ static const struct sysfs_ops bus_sysfs_ops = { .store = bus_attr_store, }; -int bus_create_file(struct bus_type *bus, struct bus_attribute *attr) +int bus_create_file(const struct bus_type *bus, struct bus_attribute *attr) { + struct subsys_private *sp = bus_to_subsys(bus); int error; - if (bus_get(bus)) { - error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr); - bus_put(bus); - } else - error = -EINVAL; + + if (!sp) + return -EINVAL; + + error = sysfs_create_file(&sp->subsys.kobj, &attr->attr); + + subsys_put(sp); return error; } EXPORT_SYMBOL_GPL(bus_create_file); -void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) +void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr) { - if (bus_get(bus)) { - sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr); - bus_put(bus); - } + struct subsys_private *sp = bus_to_subsys(bus); + + if (!sp) + return; + + sysfs_remove_file(&sp->subsys.kobj, &attr->attr); + subsys_put(sp); } EXPORT_SYMBOL_GPL(bus_remove_file); static void bus_release(struct kobject *kobj) { struct subsys_private *priv = to_subsys_private(kobj); - struct bus_type *bus = priv->bus; + lockdep_unregister_key(&priv->lock_key); kfree(priv); - bus->p = NULL; } -static struct kobj_type bus_ktype = { +static const struct kobj_type bus_ktype = { .sysfs_ops = &bus_sysfs_ops, .release = bus_release, }; -static int bus_uevent_filter(struct kset *kset, struct kobject *kobj) +static int bus_uevent_filter(const struct kobject *kobj) { - struct kobj_type *ktype = get_ktype(kobj); + const struct kobj_type *ktype = get_ktype(kobj); if (ktype == &bus_ktype) return 1; @@ -175,30 +231,24 @@ static const struct kset_uevent_ops bus_uevent_ops = { .filter = bus_uevent_filter, }; -static struct kset *bus_kset; - /* Manually detach a device from its associated driver. */ static ssize_t unbind_store(struct device_driver *drv, const char *buf, size_t count) { - struct bus_type *bus = bus_get(drv->bus); + const struct bus_type *bus = bus_get(drv->bus); struct device *dev; int err = -ENODEV; dev = bus_find_device_by_name(bus, NULL, buf); if (dev && dev->driver == drv) { - if (dev->parent && dev->bus->need_parent_lock) - device_lock(dev->parent); - device_release_driver(dev); - if (dev->parent && dev->bus->need_parent_lock) - device_unlock(dev->parent); + device_driver_detach(dev); err = count; } put_device(dev); bus_put(bus); return err; } -static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, S_IWUSR, NULL, unbind_store); +static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store); /* * Manually attach a device to a driver. @@ -208,50 +258,55 @@ static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, S_IWUSR, NULL, unbind_store); static ssize_t bind_store(struct device_driver *drv, const char *buf, size_t count) { - struct bus_type *bus = bus_get(drv->bus); + const struct bus_type *bus = bus_get(drv->bus); struct device *dev; int err = -ENODEV; dev = bus_find_device_by_name(bus, NULL, buf); - if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { - if (dev->parent && bus->need_parent_lock) - device_lock(dev->parent); - device_lock(dev); - err = driver_probe_device(drv, dev); - device_unlock(dev); - if (dev->parent && bus->need_parent_lock) - device_unlock(dev->parent); - - if (err > 0) { + if (dev && driver_match_device(drv, dev)) { + err = device_driver_attach(drv, dev); + if (!err) { /* success */ err = count; - } else if (err == 0) { - /* driver didn't accept device */ - err = -ENODEV; } } put_device(dev); bus_put(bus); return err; } -static DRIVER_ATTR_IGNORE_LOCKDEP(bind, S_IWUSR, NULL, bind_store); +static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store); -static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf) +static ssize_t drivers_autoprobe_show(const struct bus_type *bus, char *buf) { - return sprintf(buf, "%d\n", bus->p->drivers_autoprobe); + struct subsys_private *sp = bus_to_subsys(bus); + int ret; + + if (!sp) + return -EINVAL; + + ret = sysfs_emit(buf, "%d\n", sp->drivers_autoprobe); + subsys_put(sp); + return ret; } -static ssize_t store_drivers_autoprobe(struct bus_type *bus, +static ssize_t drivers_autoprobe_store(const struct bus_type *bus, const char *buf, size_t count) { + struct subsys_private *sp = bus_to_subsys(bus); + + if (!sp) + return -EINVAL; + if (buf[0] == '0') - bus->p->drivers_autoprobe = 0; + sp->drivers_autoprobe = 0; else - bus->p->drivers_autoprobe = 1; + sp->drivers_autoprobe = 1; + + subsys_put(sp); return count; } -static ssize_t store_drivers_probe(struct bus_type *bus, +static ssize_t drivers_probe_store(const struct bus_type *bus, const char *buf, size_t count) { struct device *dev; @@ -279,6 +334,19 @@ static struct device *next_device(struct klist_iter *i) return dev; } +static struct device *prev_device(struct klist_iter *i) +{ + struct klist_node *n = klist_prev(i); + struct device *dev = NULL; + struct device_private *dev_prv; + + if (n) { + dev_prv = to_device_private_bus(n); + dev = dev_prv->device; + } + return dev; +} + /** * bus_for_each_dev - device iterator. * @bus: bus type. @@ -298,21 +366,23 @@ static struct device *next_device(struct klist_iter *i) * to retain this data, it should do so, and increment the reference * count in the supplied callback. */ -int bus_for_each_dev(struct bus_type *bus, struct device *start, - void *data, int (*fn)(struct device *, void *)) +int bus_for_each_dev(const struct bus_type *bus, struct device *start, + void *data, device_iter_t fn) { + struct subsys_private *sp = bus_to_subsys(bus); struct klist_iter i; struct device *dev; int error = 0; - if (!bus || !bus->p) + if (!sp) return -EINVAL; - klist_iter_init_node(&bus->p->klist_devices, &i, + klist_iter_init_node(&sp->klist_devices, &i, (start ? &start->p->knode_bus : NULL)); while (!error && (dev = next_device(&i))) error = fn(dev, data); klist_iter_exit(&i); + subsys_put(sp); return error; } EXPORT_SYMBOL_GPL(bus_for_each_dev); @@ -332,90 +402,55 @@ EXPORT_SYMBOL_GPL(bus_for_each_dev); * if it does. If the callback returns non-zero, this function will * return to the caller and not iterate over any more devices. */ -struct device *bus_find_device(struct bus_type *bus, - struct device *start, void *data, - int (*match)(struct device *dev, void *data)) +struct device *bus_find_device(const struct bus_type *bus, + struct device *start, const void *data, + device_match_t match) { + struct subsys_private *sp = bus_to_subsys(bus); struct klist_iter i; struct device *dev; - if (!bus || !bus->p) + if (!sp) return NULL; - klist_iter_init_node(&bus->p->klist_devices, &i, + klist_iter_init_node(&sp->klist_devices, &i, (start ? &start->p->knode_bus : NULL)); - while ((dev = next_device(&i))) - if (match(dev, data) && get_device(dev)) + while ((dev = next_device(&i))) { + if (match(dev, data)) { + get_device(dev); break; + } + } klist_iter_exit(&i); + subsys_put(sp); return dev; } EXPORT_SYMBOL_GPL(bus_find_device); -static int match_name(struct device *dev, void *data) -{ - const char *name = data; - - return sysfs_streq(name, dev_name(dev)); -} - -/** - * bus_find_device_by_name - device iterator for locating a particular device of a specific name - * @bus: bus type - * @start: Device to begin with - * @name: name of the device to match - * - * This is similar to the bus_find_device() function above, but it handles - * searching by a name automatically, no need to write another strcmp matching - * function. - */ -struct device *bus_find_device_by_name(struct bus_type *bus, - struct device *start, const char *name) -{ - return bus_find_device(bus, start, (void *)name, match_name); -} -EXPORT_SYMBOL_GPL(bus_find_device_by_name); - -/** - * subsys_find_device_by_id - find a device with a specific enumeration number - * @subsys: subsystem - * @id: index 'id' in struct device - * @hint: device to check first - * - * Check the hint's next object and if it is a match return it directly, - * otherwise, fall back to a full list search. Either way a reference for - * the returned object is taken. - */ -struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id, - struct device *hint) +struct device *bus_find_device_reverse(const struct bus_type *bus, + struct device *start, const void *data, + device_match_t match) { + struct subsys_private *sp = bus_to_subsys(bus); struct klist_iter i; struct device *dev; - if (!subsys) + if (!sp) return NULL; - if (hint) { - klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus); - dev = next_device(&i); - if (dev && dev->id == id && get_device(dev)) { - klist_iter_exit(&i); - return dev; - } - klist_iter_exit(&i); - } - - klist_iter_init_node(&subsys->p->klist_devices, &i, NULL); - while ((dev = next_device(&i))) { - if (dev->id == id && get_device(dev)) { - klist_iter_exit(&i); - return dev; + klist_iter_init_node(&sp->klist_devices, &i, + (start ? &start->p->knode_bus : NULL)); + while ((dev = prev_device(&i))) { + if (match(dev, data)) { + get_device(dev); + break; } } klist_iter_exit(&i); - return NULL; + subsys_put(sp); + return dev; } -EXPORT_SYMBOL_GPL(subsys_find_device_by_id); +EXPORT_SYMBOL_GPL(bus_find_device_reverse); static struct device_driver *next_driver(struct klist_iter *i) { @@ -448,21 +483,23 @@ static struct device_driver *next_driver(struct klist_iter *i) * in the callback. It must also be sure to increment the refcount * so it doesn't disappear before returning to the caller. */ -int bus_for_each_drv(struct bus_type *bus, struct device_driver *start, +int bus_for_each_drv(const struct bus_type *bus, struct device_driver *start, void *data, int (*fn)(struct device_driver *, void *)) { + struct subsys_private *sp = bus_to_subsys(bus); struct klist_iter i; struct device_driver *drv; int error = 0; - if (!bus) + if (!sp) return -EINVAL; - klist_iter_init_node(&bus->p->klist_drivers, &i, + klist_iter_init_node(&sp->klist_drivers, &i, start ? &start->p->knode_bus : NULL); while ((drv = next_driver(&i)) && !error) error = fn(drv, data); klist_iter_exit(&i); + subsys_put(sp); return error; } EXPORT_SYMBOL_GPL(bus_for_each_drv); @@ -477,32 +514,46 @@ 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; } @@ -514,20 +565,20 @@ 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) - device_initial_probe(dev); + 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); } /** @@ -542,21 +593,20 @@ 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); @@ -564,7 +614,14 @@ 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) @@ -586,11 +643,10 @@ static void remove_bind_files(struct device_driver *drv) driver_remove_file(drv, &driver_attr_unbind); } -static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe); -static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO, - show_drivers_autoprobe, store_drivers_autoprobe); +static BUS_ATTR_WO(drivers_probe); +static BUS_ATTR_RW(drivers_autoprobe); -static int add_probe_files(struct bus_type *bus) +static int add_probe_files(const struct bus_type *bus) { int retval; @@ -605,7 +661,7 @@ out: return retval; } -static void remove_probe_files(struct bus_type *bus) +static void remove_probe_files(const struct bus_type *bus) { bus_remove_file(bus, &bus_attr_drivers_autoprobe); bus_remove_file(bus, &bus_attr_drivers_probe); @@ -621,32 +677,24 @@ static ssize_t uevent_store(struct device_driver *drv, const char *buf, } static DRIVER_ATTR_WO(uevent); -static void driver_attach_async(void *_drv, async_cookie_t cookie) -{ - struct device_driver *drv = _drv; - int ret; - - ret = driver_attach(drv); - - pr_debug("bus: '%s': driver %s async attach completed: %d\n", - drv->bus->name, drv->name, ret); -} - /** * bus_add_driver - Add a driver to the bus. * @drv: driver. */ int bus_add_driver(struct device_driver *drv) { - struct bus_type *bus; + struct subsys_private *sp = bus_to_subsys(drv->bus); struct driver_private *priv; int error = 0; - bus = bus_get(drv->bus); - if (!bus) + if (!sp) return -EINVAL; - pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name); + /* + * Reference in sp is now incremented and will be dropped when + * the driver is removed from the bus + */ + pr_debug("bus: '%s': add driver %s\n", sp->bus->name, drv->name); priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) { @@ -656,35 +704,34 @@ int bus_add_driver(struct device_driver *drv) klist_init(&priv->klist_devices, NULL, NULL); priv->driver = drv; drv->p = priv; - priv->kobj.kset = bus->p->drivers_kset; + priv->kobj.kset = sp->drivers_kset; error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL, "%s", drv->name); if (error) goto out_unregister; - klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers); - if (drv->bus->p->drivers_autoprobe) { - if (driver_allows_async_probing(drv)) { - pr_debug("bus: '%s': probing driver %s asynchronously\n", - drv->bus->name, drv->name); - async_schedule(driver_attach_async, drv); - } else { - error = driver_attach(drv); - if (error) - goto out_unregister; - } + klist_add_tail(&priv->knode_bus, &sp->klist_drivers); + if (sp->drivers_autoprobe) { + error = driver_attach(drv); + if (error) + goto out_del_list; + } + error = module_add_driver(drv->owner, drv); + if (error) { + printk(KERN_ERR "%s: failed to create module links for %s\n", + __func__, drv->name); + goto out_detach; } - module_add_driver(drv->owner, drv); error = driver_create_file(drv, &driver_attr_uevent); if (error) { printk(KERN_ERR "%s: uevent attr (%s) failed\n", __func__, drv->name); } - error = driver_add_groups(drv, bus->drv_groups); + error = driver_add_groups(drv, sp->bus->drv_groups); if (error) { /* How the hell do we get out of this pickle? Give up */ - printk(KERN_ERR "%s: driver_create_groups(%s) failed\n", + printk(KERN_ERR "%s: driver_add_groups(%s) failed\n", __func__, drv->name); } @@ -699,12 +746,16 @@ int bus_add_driver(struct device_driver *drv) return 0; +out_detach: + driver_detach(drv); +out_del_list: + klist_del(&priv->knode_bus); out_unregister: kobject_put(&priv->kobj); /* drv->p is freed in driver_release() */ drv->p = NULL; out_put_bus: - bus_put(bus); + subsys_put(sp); return error; } @@ -718,19 +769,29 @@ out_put_bus: */ void bus_remove_driver(struct device_driver *drv) { - if (!drv->bus) + struct subsys_private *sp = bus_to_subsys(drv->bus); + + if (!sp) return; + pr_debug("bus: '%s': remove driver %s\n", sp->bus->name, drv->name); + if (!drv->suppress_bind_attrs) remove_bind_files(drv); - driver_remove_groups(drv, drv->bus->drv_groups); + driver_remove_groups(drv, sp->bus->drv_groups); driver_remove_file(drv, &driver_attr_uevent); klist_remove(&drv->p->knode_bus); - pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name); driver_detach(drv); module_remove_driver(drv); kobject_put(&drv->p->kobj); - bus_put(drv->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_driver() + */ + subsys_put(sp); + subsys_put(sp); } /* Helper for bus_rescan_devices's iter */ @@ -757,7 +818,7 @@ static int __must_check bus_rescan_devices_helper(struct device *dev, * attached and rescan it against existing drivers to see if it matches * any by calling device_attach() for the unbound devices. */ -int bus_rescan_devices(struct bus_type *bus) +int bus_rescan_devices(const struct bus_type *bus) { return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper); } @@ -774,46 +835,12 @@ EXPORT_SYMBOL_GPL(bus_rescan_devices); */ int device_reprobe(struct device *dev) { - if (dev->driver) { - if (dev->parent && dev->bus->need_parent_lock) - device_lock(dev->parent); - device_release_driver(dev); - if (dev->parent && dev->bus->need_parent_lock) - device_unlock(dev->parent); - } + if (dev->driver) + device_driver_detach(dev); return bus_rescan_devices_helper(dev, NULL); } EXPORT_SYMBOL_GPL(device_reprobe); -/** - * find_bus - locate bus by name. - * @name: name of bus. - * - * Call kset_find_obj() to iterate over list of buses to - * find a bus by name. Return bus if found. - * - * Note that kset_find_obj increments bus' reference count. - */ -#if 0 -struct bus_type *find_bus(char *name) -{ - struct kobject *k = kset_find_obj(bus_kset, name); - return k ? to_bus(k) : NULL; -} -#endif /* 0 */ - -static int bus_add_groups(struct bus_type *bus, - const struct attribute_group **groups) -{ - return sysfs_create_groups(&bus->p->subsys.kobj, groups); -} - -static void bus_remove_groups(struct bus_type *bus, - const struct attribute_group **groups) -{ - sysfs_remove_groups(&bus->p->subsys.kobj, groups); -} - static void klist_devices_get(struct klist_node *n) { struct device_private *dev_prv = to_device_private_bus(n); @@ -830,15 +857,30 @@ static void klist_devices_put(struct klist_node *n) put_device(dev); } -static ssize_t bus_uevent_store(struct bus_type *bus, +static ssize_t bus_uevent_store(const struct bus_type *bus, const char *buf, size_t count) { - int rc; + struct subsys_private *sp = bus_to_subsys(bus); + int ret; - rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count); - return rc ? rc : count; + if (!sp) + return -EINVAL; + + ret = kobject_synth_uevent(&sp->subsys.kobj, buf, count); + subsys_put(sp); + + if (ret) + return ret; + return count; } -static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store); +/* + * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO() + * here, but can not use it as earlier in the file we have + * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store + * function name. + */ +static struct bus_attribute bus_attr_uevent = __ATTR(uevent, 0200, NULL, + bus_uevent_store); /** * bus_register - register a driver-core subsystem @@ -848,27 +890,28 @@ static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store); * infrastructure, then register the children subsystems it has: * the devices and drivers that belong to the subsystem. */ -int bus_register(struct bus_type *bus) +int bus_register(const struct bus_type *bus) { int retval; struct subsys_private *priv; - struct lock_class_key *key = &bus->lock_key; + struct kobject *bus_kobj; + struct lock_class_key *key; priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL); if (!priv) return -ENOMEM; priv->bus = bus; - bus->p = priv; BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier); - retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name); + bus_kobj = &priv->subsys.kobj; + retval = kobject_set_name(bus_kobj, "%s", bus->name); if (retval) goto out; - priv->subsys.kobj.kset = bus_kset; - priv->subsys.kobj.ktype = &bus_ktype; + bus_kobj->kset = bus_kset; + bus_kobj->ktype = &bus_ktype; priv->drivers_autoprobe = 1; retval = kset_register(&priv->subsys); @@ -879,21 +922,21 @@ int bus_register(struct bus_type *bus) if (retval) goto bus_uevent_fail; - priv->devices_kset = kset_create_and_add("devices", NULL, - &priv->subsys.kobj); + priv->devices_kset = kset_create_and_add("devices", NULL, bus_kobj); if (!priv->devices_kset) { retval = -ENOMEM; goto bus_devices_fail; } - priv->drivers_kset = kset_create_and_add("drivers", NULL, - &priv->subsys.kobj); + priv->drivers_kset = kset_create_and_add("drivers", NULL, bus_kobj); if (!priv->drivers_kset) { retval = -ENOMEM; goto bus_drivers_fail; } INIT_LIST_HEAD(&priv->interfaces); + key = &priv->lock_key; + lockdep_register_key(key); __mutex_init(&priv->mutex, "subsys mutex", key); klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put); klist_init(&priv->klist_drivers, NULL, NULL); @@ -902,7 +945,7 @@ int bus_register(struct bus_type *bus) if (retval) goto bus_probe_files_fail; - retval = bus_add_groups(bus, bus->bus_groups); + retval = sysfs_create_groups(bus_kobj, bus->bus_groups); if (retval) goto bus_groups_fail; @@ -912,16 +955,17 @@ int bus_register(struct bus_type *bus) bus_groups_fail: remove_probe_files(bus); bus_probe_files_fail: - kset_unregister(bus->p->drivers_kset); + kset_unregister(priv->drivers_kset); bus_drivers_fail: - kset_unregister(bus->p->devices_kset); + kset_unregister(priv->devices_kset); bus_devices_fail: bus_remove_file(bus, &bus_attr_uevent); bus_uevent_fail: - kset_unregister(&bus->p->subsys); + kset_unregister(&priv->subsys); + /* Above kset_unregister() will kfree @priv */ + priv = NULL; out: - kfree(bus->p); - bus->p = NULL; + kfree(priv); return retval; } EXPORT_SYMBOL_GPL(bus_register); @@ -933,43 +977,82 @@ EXPORT_SYMBOL_GPL(bus_register); * Unregister the child subsystems and the bus itself. * Finally, we call bus_put() to release the refcount */ -void bus_unregister(struct bus_type *bus) +void bus_unregister(const struct bus_type *bus) { + struct subsys_private *sp = bus_to_subsys(bus); + struct kobject *bus_kobj; + + if (!sp) + return; + pr_debug("bus: '%s': unregistering\n", bus->name); - if (bus->dev_root) - device_unregister(bus->dev_root); - bus_remove_groups(bus, bus->bus_groups); + if (sp->dev_root) + device_unregister(sp->dev_root); + + bus_kobj = &sp->subsys.kobj; + sysfs_remove_groups(bus_kobj, bus->bus_groups); remove_probe_files(bus); - kset_unregister(bus->p->drivers_kset); - kset_unregister(bus->p->devices_kset); bus_remove_file(bus, &bus_attr_uevent); - kset_unregister(&bus->p->subsys); + + kset_unregister(sp->drivers_kset); + kset_unregister(sp->devices_kset); + kset_unregister(&sp->subsys); + subsys_put(sp); } EXPORT_SYMBOL_GPL(bus_unregister); -int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb) +int bus_register_notifier(const struct bus_type *bus, struct notifier_block *nb) { - return blocking_notifier_chain_register(&bus->p->bus_notifier, nb); + struct subsys_private *sp = bus_to_subsys(bus); + int retval; + + if (!sp) + return -EINVAL; + + retval = blocking_notifier_chain_register(&sp->bus_notifier, nb); + subsys_put(sp); + return retval; } EXPORT_SYMBOL_GPL(bus_register_notifier); -int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb) +int bus_unregister_notifier(const struct bus_type *bus, struct notifier_block *nb) { - return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb); + struct subsys_private *sp = bus_to_subsys(bus); + int retval; + + if (!sp) + return -EINVAL; + retval = blocking_notifier_chain_unregister(&sp->bus_notifier, nb); + subsys_put(sp); + return retval; } EXPORT_SYMBOL_GPL(bus_unregister_notifier); -struct kset *bus_get_kset(struct bus_type *bus) +void bus_notify(struct device *dev, enum bus_notifier_event value) { - return &bus->p->subsys; + struct subsys_private *sp = bus_to_subsys(dev->bus); + + if (!sp) + return; + + blocking_notifier_call_chain(&sp->bus_notifier, value, dev); + subsys_put(sp); } -EXPORT_SYMBOL_GPL(bus_get_kset); -struct klist *bus_get_device_klist(struct bus_type *bus) +struct kset *bus_get_kset(const struct bus_type *bus) { - return &bus->p->klist_devices; + struct subsys_private *sp = bus_to_subsys(bus); + struct kset *kset; + + if (!sp) + return NULL; + + kset = &sp->subsys; + subsys_put(sp); + + return kset; } -EXPORT_SYMBOL_GPL(bus_get_device_klist); +EXPORT_SYMBOL_GPL(bus_get_kset); /* * Yes, this forcibly breaks the klist abstraction temporarily. It @@ -998,17 +1081,20 @@ static void device_insertion_sort_klist(struct device *a, struct list_head *list list_move_tail(&a->p->knode_bus.n_node, list); } -void bus_sort_breadthfirst(struct bus_type *bus, +void bus_sort_breadthfirst(const struct bus_type *bus, int (*compare)(const struct device *a, const struct device *b)) { + struct subsys_private *sp = bus_to_subsys(bus); LIST_HEAD(sorted_devices); struct klist_node *n, *tmp; struct device_private *dev_prv; struct device *dev; struct klist *device_klist; - device_klist = bus_get_device_klist(bus); + if (!sp) + return; + device_klist = &sp->klist_devices; spin_lock(&device_klist->k_lock); list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) { @@ -1018,13 +1104,19 @@ void bus_sort_breadthfirst(struct bus_type *bus, } list_splice(&sorted_devices, &device_klist->k_list); spin_unlock(&device_klist->k_lock); + subsys_put(sp); } EXPORT_SYMBOL_GPL(bus_sort_breadthfirst); +struct subsys_dev_iter { + struct klist_iter ki; + const struct device_type *type; +}; + /** * 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 * @@ -1033,17 +1125,16 @@ EXPORT_SYMBOL_GPL(bus_sort_breadthfirst); * otherwise if it is NULL, the iteration starts at the beginning of * the list. */ -void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys, - struct device *start, const struct device_type *type) +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; } -EXPORT_SYMBOL_GPL(subsys_dev_iter_init); /** * subsys_dev_iter_next - iterate to the next device @@ -1057,7 +1148,7 @@ EXPORT_SYMBOL_GPL(subsys_dev_iter_init); * free to do whatever it wants to do with the device including * calling back into subsys code. */ -struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter) +static struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter) { struct klist_node *knode; struct device *dev; @@ -1071,7 +1162,6 @@ struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter) return dev; } } -EXPORT_SYMBOL_GPL(subsys_dev_iter_next); /** * subsys_dev_iter_exit - finish iteration @@ -1080,34 +1170,38 @@ EXPORT_SYMBOL_GPL(subsys_dev_iter_next); * Finish an iteration. Always call this function after iteration is * complete whether the iteration ran till the end or not. */ -void subsys_dev_iter_exit(struct subsys_dev_iter *iter) +static void subsys_dev_iter_exit(struct subsys_dev_iter *iter) { klist_iter_exit(&iter->ki); } -EXPORT_SYMBOL_GPL(subsys_dev_iter_exit); 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; } @@ -1115,26 +1209,34 @@ 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); - - bus_put(subsys); + mutex_unlock(&sp->mutex); + + /* + * 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); @@ -1143,10 +1245,11 @@ static void system_root_device_release(struct device *dev) kfree(dev); } -static int subsys_register(struct bus_type *subsys, +static int subsys_register(const struct bus_type *subsys, const struct attribute_group **groups, struct kobject *parent_of_root) { + struct subsys_private *sp; struct device *dev; int err; @@ -1154,6 +1257,12 @@ static int subsys_register(struct bus_type *subsys, if (err < 0) return err; + sp = bus_to_subsys(subsys); + if (!sp) { + err = -EINVAL; + goto err_sp; + } + dev = kzalloc(sizeof(struct device), GFP_KERNEL); if (!dev) { err = -ENOMEM; @@ -1172,7 +1281,8 @@ static int subsys_register(struct bus_type *subsys, if (err < 0) goto err_dev_reg; - subsys->dev_root = dev; + sp->dev_root = dev; + subsys_put(sp); return 0; err_dev_reg: @@ -1181,6 +1291,8 @@ err_dev_reg: err_name: kfree(dev); err_dev: + subsys_put(sp); +err_sp: bus_unregister(subsys); return err; } @@ -1203,7 +1315,7 @@ err_dev: * directory itself and not some create fake root-device placed in * /sys/devices/system/<name>. */ -int subsys_system_register(struct bus_type *subsys, +int subsys_system_register(const struct bus_type *subsys, const struct attribute_group **groups) { return subsys_register(subsys, groups, &system_kset->kobj); @@ -1216,17 +1328,17 @@ EXPORT_SYMBOL_GPL(subsys_system_register); * @groups: default attributes for the root device * * All 'virtual' subsystems have a /sys/devices/system/<name> root device - * with the name of the subystem. The root device can carry subsystem-wide + * with the name of the subsystem. The root device can carry subsystem-wide * attributes. All registered devices are below this single root device. * There's no restriction on device naming. This is for kernel software * constructs which need sysfs interface. */ -int subsys_virtual_register(struct bus_type *subsys, +int subsys_virtual_register(const struct bus_type *subsys, const struct attribute_group **groups) { struct kobject *virtual_dir; - virtual_dir = virtual_device_parent(NULL); + virtual_dir = virtual_device_parent(); if (!virtual_dir) return -ENOMEM; @@ -1234,6 +1346,82 @@ int subsys_virtual_register(struct bus_type *subsys, } EXPORT_SYMBOL_GPL(subsys_virtual_register); +/** + * driver_find - locate driver on a bus by its name. + * @name: name of the driver. + * @bus: bus to scan for the driver. + * + * Call kset_find_obj() to iterate over list of drivers on + * a bus to find driver by name. Return driver if found. + * + * This routine provides no locking to prevent the driver it returns + * from being unregistered or unloaded while the caller is using it. + * The caller is responsible for preventing this. + */ +struct device_driver *driver_find(const char *name, const struct bus_type *bus) +{ + struct subsys_private *sp = bus_to_subsys(bus); + struct kobject *k; + struct driver_private *priv; + + if (!sp) + return NULL; + + k = kset_find_obj(sp->drivers_kset, name); + subsys_put(sp); + if (!k) + return NULL; + + priv = to_driver(k); + + /* Drop reference added by kset_find_obj() */ + kobject_put(k); + return priv->driver; +} +EXPORT_SYMBOL_GPL(driver_find); + +/* + * Warning, the value could go to "removed" instantly after calling this function, so be very + * careful when calling it... + */ +bool bus_is_registered(const struct bus_type *bus) +{ + struct subsys_private *sp = bus_to_subsys(bus); + bool is_initialized = false; + + if (sp) { + is_initialized = true; + subsys_put(sp); + } + return is_initialized; +} + +/** + * bus_get_dev_root - return a pointer to the "device root" of a bus + * @bus: bus to return the device root of. + * + * If a bus has a "device root" structure, return it, WITH THE REFERENCE + * COUNT INCREMENTED. + * + * Note, when finished with the device, a call to put_device() is required. + * + * If the device root is not present (or bus is not a valid pointer), NULL + * will be returned. + */ +struct device *bus_get_dev_root(const struct bus_type *bus) +{ + struct subsys_private *sp = bus_to_subsys(bus); + struct device *dev_root; + + if (!sp) + return NULL; + + dev_root = get_device(sp->dev_root); + subsys_put(sp); + return dev_root; +} +EXPORT_SYMBOL_GPL(bus_get_dev_root); + int __init buses_init(void) { bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL); @@ -1241,8 +1429,13 @@ int __init buses_init(void) return -ENOMEM; system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj); - if (!system_kset) + if (!system_kset) { + /* Do error handling here as devices_init() do */ + kset_unregister(bus_kset); + bus_kset = NULL; + pr_err("%s: failed to create and add kset 'bus'\n", __func__); return -ENOMEM; + } return 0; } |