From 864062457a2e444227bd368ca5f2a2b740de604f Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Wed, 14 Mar 2007 03:25:56 +0100 Subject: [PATCH] driver core: fix namespace issue with devices assigned to classes - uses a kset in "struct class" to keep track of all directories belonging to this class - merges with the /sys/devices/virtual logic. - removes the namespace-dir if the last member of that class leaves the directory. There may be locking or refcounting fixes left, I stopped when it seemed to work with network and sound modules. :) From: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- drivers/base/class.c | 2 +- drivers/base/core.c | 82 ++++++++++++++++++++++++++++++++--------- include/linux/device.h | 3 +- include/linux/kobject.h | 2 + lib/kobject.c | 12 +++++- lib/kobject_uevent.c | 16 +++++--- 6 files changed, 89 insertions(+), 28 deletions(-) diff --git a/drivers/base/class.c b/drivers/base/class.c index d5968128be..80bbb20746 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -145,6 +145,7 @@ int class_register(struct class * cls) INIT_LIST_HEAD(&cls->children); INIT_LIST_HEAD(&cls->devices); INIT_LIST_HEAD(&cls->interfaces); + kset_init(&cls->class_dirs); init_MUTEX(&cls->sem); error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name); if (error) @@ -163,7 +164,6 @@ int class_register(struct class * cls) void class_unregister(struct class * cls) { pr_debug("device class '%s': unregistering\n", cls->name); - kobject_unregister(cls->virtual_dir); remove_class_attrs(cls); subsystem_unregister(&cls->subsys); } diff --git a/drivers/base/core.c b/drivers/base/core.c index db3a151be4..658eae5dac 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -477,34 +477,58 @@ static struct kobject * get_device_parent(struct device *dev, return NULL; } #else -static struct kobject * virtual_device_parent(struct device *dev) +static struct kobject *virtual_device_parent(struct device *dev) { - if (!dev->class) - return ERR_PTR(-ENODEV); - - if (!dev->class->virtual_dir) { - static struct kobject *virtual_dir = NULL; + static struct kobject *virtual_dir = NULL; - if (!virtual_dir) - virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual"); - dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name); - } + if (!virtual_dir) + virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual"); - return dev->class->virtual_dir; + return virtual_dir; } static struct kobject * get_device_parent(struct device *dev, struct device *parent) { - /* if this is a class device, and has no parent, create one */ - if ((dev->class) && (parent == NULL)) { - return virtual_device_parent(dev); - } else if (parent) + if (dev->class) { + struct kobject *kobj = NULL; + struct kobject *parent_kobj; + struct kobject *k; + + /* + * If we have no parent, we live in "virtual". + * Class-devices with a bus-device as parent, live + * in a class-directory to prevent namespace collisions. + */ + if (parent == NULL) + parent_kobj = virtual_device_parent(dev); + else if (parent->class) + return &parent->kobj; + else + parent_kobj = &parent->kobj; + + /* find our class-directory at the parent and reference it */ + spin_lock(&dev->class->class_dirs.list_lock); + list_for_each_entry(k, &dev->class->class_dirs.list, entry) + if (k->parent == parent_kobj) { + kobj = kobject_get(k); + break; + } + spin_unlock(&dev->class->class_dirs.list_lock); + if (kobj) + return kobj; + + /* or create a new class-directory at the parent device */ + return kobject_kset_add_dir(&dev->class->class_dirs, + parent_kobj, dev->class->name); + } + + if (parent) return &parent->kobj; return NULL; } - #endif + static int setup_parent(struct device *dev, struct device *parent) { struct kobject *kobj; @@ -541,7 +565,6 @@ int device_add(struct device *dev) pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); parent = get_device(dev->parent); - error = setup_parent(dev, parent); if (error) goto Error; @@ -787,6 +810,31 @@ void device_del(struct device * dev) /* remove the device from the class list */ list_del_init(&dev->node); up(&dev->class->sem); + + /* If we live in a parent class-directory, unreference it */ + if (dev->kobj.parent->kset == &dev->class->class_dirs) { + struct device *d; + int other = 0; + + /* + * if we are the last child of our class, delete + * our class-directory at this parent + */ + down(&dev->class->sem); + list_for_each_entry(d, &dev->class->devices, node) { + if (d == dev) + continue; + if (d->kobj.parent == dev->kobj.parent) { + other = 1; + break; + } + } + if (!other) + kobject_del(dev->kobj.parent); + + kobject_put(dev->kobj.parent); + up(&dev->class->sem); + } } device_remove_file(dev, &dev->uevent_attr); device_remove_groups(dev); diff --git a/include/linux/device.h b/include/linux/device.h index 5cf30e95c8..de0e73eae6 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -181,10 +181,9 @@ struct class { struct list_head children; struct list_head devices; struct list_head interfaces; + struct kset class_dirs; struct semaphore sem; /* locks both the children and interfaces lists */ - struct kobject *virtual_dir; - struct class_attribute * class_attrs; struct class_device_attribute * class_dev_attrs; struct device_attribute * dev_attrs; diff --git a/include/linux/kobject.h b/include/linux/kobject.h index b850e03105..d37cd7f10e 100644 --- a/include/linux/kobject.h +++ b/include/linux/kobject.h @@ -89,6 +89,8 @@ extern void kobject_unregister(struct kobject *); extern struct kobject * kobject_get(struct kobject *); extern void kobject_put(struct kobject *); +extern struct kobject *kobject_kset_add_dir(struct kset *kset, + struct kobject *, const char *); extern struct kobject *kobject_add_dir(struct kobject *, const char *); extern char * kobject_get_path(struct kobject *, gfp_t); diff --git a/lib/kobject.c b/lib/kobject.c index 057921c594..f664551556 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -488,13 +488,15 @@ static struct kobj_type dir_ktype = { }; /** - * kobject_add_dir - add sub directory of object. + * kobject__kset_add_dir - add sub directory of object. + * @kset: kset the directory is belongs to. * @parent: object in which a directory is created. * @name: directory name. * * Add a plain directory object as child of given object. */ -struct kobject *kobject_add_dir(struct kobject *parent, const char *name) +struct kobject *kobject_kset_add_dir(struct kset *kset, + struct kobject *parent, const char *name) { struct kobject *k; int ret; @@ -506,6 +508,7 @@ struct kobject *kobject_add_dir(struct kobject *parent, const char *name) if (!k) return NULL; + k->kset = kset; k->parent = parent; k->ktype = &dir_ktype; kobject_set_name(k, name); @@ -520,6 +523,11 @@ struct kobject *kobject_add_dir(struct kobject *parent, const char *name) return k; } +struct kobject *kobject_add_dir(struct kobject *parent, const char *name) +{ + return kobject_kset_add_dir(NULL, parent, name); +} + /** * kset_init - initialize a kset for use * @k: kset diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 82fc1794b6..4122f38330 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -115,6 +115,16 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, return 0; } + /* originating subsystem */ + if (uevent_ops && uevent_ops->name) + subsystem = uevent_ops->name(kset, kobj); + else + subsystem = kobject_name(&kset->kobj); + if (!subsystem) { + pr_debug("unset subsytem caused the event to drop!\n"); + return 0; + } + /* environment index */ envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); if (!envp) @@ -134,12 +144,6 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, goto exit; } - /* originating subsystem */ - if (uevent_ops && uevent_ops->name) - subsystem = uevent_ops->name(kset, kobj); - else - subsystem = kobject_name(&kset->kobj); - /* event environemnt for helper process only */ envp[i++] = "HOME=/"; envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; -- 2.39.5