diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-dev | 20 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs.txt | 6 | ||||
| -rw-r--r-- | block/genhd.c | 5 | ||||
| -rw-r--r-- | drivers/base/class.c | 4 | ||||
| -rw-r--r-- | drivers/base/core.c | 83 | ||||
| -rw-r--r-- | drivers/usb/core/devio.c | 5 | ||||
| -rw-r--r-- | include/linux/device.h | 3 |
7 files changed, 124 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/sysfs-dev b/Documentation/ABI/testing/sysfs-dev new file mode 100644 index 000000000000..a9f2b8b0530f --- /dev/null +++ b/Documentation/ABI/testing/sysfs-dev @@ -0,0 +1,20 @@ +What: /sys/dev +Date: April 2008 +KernelVersion: 2.6.26 +Contact: Dan Williams <dan.j.williams@intel.com> +Description: The /sys/dev tree provides a method to look up the sysfs + path for a device using the information returned from + stat(2). There are two directories, 'block' and 'char', + beneath /sys/dev containing symbolic links with names of + the form "<major>:<minor>". These links point to the + corresponding sysfs path for the given device. + + Example: + $ readlink /sys/dev/block/8:32 + ../../block/sdc + + Entries in /sys/dev/char and /sys/dev/block will be + dynamically created and destroyed as devices enter and + leave the system. + +Users: mdadm <linux-raid@vger.kernel.org> diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index 7f27b8f840d0..9e9c348275a9 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -248,6 +248,7 @@ The top level sysfs directory looks like: block/ bus/ class/ +dev/ devices/ firmware/ net/ @@ -274,6 +275,11 @@ fs/ contains a directory for some filesystems. Currently each filesystem wanting to export attributes must create its own hierarchy below fs/ (see ./fuse.txt for an example). +dev/ contains two directories char/ and block/. Inside these two +directories there are symlinks named <major>:<minor>. These symlinks +point to the sysfs directory for the given device. /sys/dev provides a +quick way to lookup the sysfs interface for a device from the result of +a stat(2) operation. More information can driver-model specific features can be found in Documentation/driver-model/. diff --git a/block/genhd.c b/block/genhd.c index 9074f384b097..24e3fc9095fe 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -370,7 +370,10 @@ static struct kobject *base_probe(dev_t devt, int *part, void *data) static int __init genhd_device_init(void) { - int error = class_register(&block_class); + int error; + + block_class.dev_kobj = sysfs_dev_block_kobj; + error = class_register(&block_class); if (unlikely(error)) return error; bdev_map = kobj_map_init(base_probe, &block_class_lock); diff --git a/drivers/base/class.c b/drivers/base/class.c index e085af0ff94f..71ce3ff6bdf5 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -148,6 +148,10 @@ int class_register(struct class *cls) if (error) return error; + /* set the default /sys/dev directory for devices of this class */ + if (!cls->dev_kobj) + cls->dev_kobj = sysfs_dev_char_kobj; + #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK) /* let the block class directory show up in the root of sysfs */ if (cls != &block_class) diff --git a/drivers/base/core.c b/drivers/base/core.c index ee0a51a3a41d..be9aba4dc2fb 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -27,6 +27,9 @@ int (*platform_notify)(struct device *dev) = NULL; int (*platform_notify_remove)(struct device *dev) = NULL; +static struct kobject *dev_kobj; +struct kobject *sysfs_dev_char_kobj; +struct kobject *sysfs_dev_block_kobj; #ifdef CONFIG_BLOCK static inline int device_is_not_partition(struct device *dev) @@ -776,6 +779,54 @@ int dev_set_name(struct device *dev, const char *fmt, ...) EXPORT_SYMBOL_GPL(dev_set_name); /** + * device_to_dev_kobj - select a /sys/dev/ directory for the device + * @dev: device + * + * By default we select char/ for new entries. Setting class->dev_obj + * to NULL prevents an entry from being created. class->dev_kobj must + * be set (or cleared) before any devices are registered to the class + * otherwise device_create_sys_dev_entry() and + * device_remove_sys_dev_entry() will disagree about the the presence + * of the link. + */ +static struct kobject *device_to_dev_kobj(struct device *dev) +{ + struct kobject *kobj; + + if (dev->class) + kobj = dev->class->dev_kobj; + else + kobj = sysfs_dev_char_kobj; + + return kobj; +} + +static int device_create_sys_dev_entry(struct device *dev) +{ + struct kobject *kobj = device_to_dev_kobj(dev); + int error = 0; + char devt_str[15]; + + if (kobj) { + format_dev_t(devt_str, dev->devt); + error = sysfs_create_link(kobj, &dev->kobj, devt_str); + } + + return error; +} + +static void device_remove_sys_dev_entry(struct device *dev) +{ + struct kobject *kobj = device_to_dev_kobj(dev); + char devt_str[15]; + + if (kobj) { + format_dev_t(devt_str, dev->devt); + sysfs_remove_link(kobj, devt_str); + } +} + +/** * device_add - add device to device hierarchy. * @dev: device. * @@ -829,6 +880,10 @@ int device_add(struct device *dev) error = device_create_file(dev, &devt_attr); if (error) goto ueventattrError; + + error = device_create_sys_dev_entry(dev); + if (error) + goto devtattrError; } error = device_add_class_symlinks(dev); @@ -873,6 +928,9 @@ int device_add(struct device *dev) device_remove_class_symlinks(dev); SymlinkError: if (MAJOR(dev->devt)) + device_remove_sys_dev_entry(dev); + devtattrError: + if (MAJOR(dev->devt)) device_remove_file(dev, &devt_attr); ueventattrError: device_remove_file(dev, &uevent_attr); @@ -948,8 +1006,10 @@ void device_del(struct device *dev) device_pm_remove(dev); if (parent) klist_del(&dev->knode_parent); - if (MAJOR(dev->devt)) + if (MAJOR(dev->devt)) { + device_remove_sys_dev_entry(dev); device_remove_file(dev, &devt_attr); + } if (dev->class) { device_remove_class_symlinks(dev); @@ -1074,7 +1134,25 @@ int __init devices_init(void) devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL); if (!devices_kset) return -ENOMEM; + dev_kobj = kobject_create_and_add("dev", NULL); + if (!dev_kobj) + goto dev_kobj_err; + sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj); + if (!sysfs_dev_block_kobj) + goto block_kobj_err; + sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj); + if (!sysfs_dev_char_kobj) + goto char_kobj_err; + return 0; + + char_kobj_err: + kobject_put(sysfs_dev_block_kobj); + block_kobj_err: + kobject_put(dev_kobj); + dev_kobj_err: + kset_unregister(devices_kset); + return -ENOMEM; } EXPORT_SYMBOL_GPL(device_for_each_child); @@ -1447,4 +1525,7 @@ void device_shutdown(void) dev->driver->shutdown(dev); } } + kobject_put(sysfs_dev_char_kobj); + kobject_put(sysfs_dev_block_kobj); + kobject_put(dev_kobj); } diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 54a350ccd033..6fbc8f5ab80c 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1792,6 +1792,11 @@ int __init usb_devio_init(void) usb_classdev_class = NULL; goto out; } + /* devices of this class shadow the major:minor of their parent + * device, so clear ->dev_kobj to prevent adding duplicate entries + * to /sys/dev + */ + usb_classdev_class->dev_kobj = NULL; usb_register_notify(&usbdev_nb); #endif diff --git a/include/linux/device.h b/include/linux/device.h index f71a78d123ae..e49aa74f248c 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -193,6 +193,7 @@ struct class { struct semaphore sem; /* locks children, devices, interfaces */ struct class_attribute *class_attrs; struct device_attribute *dev_attrs; + struct kobject *dev_kobj; int (*dev_uevent)(struct device *dev, struct kobj_uevent_env *env); @@ -205,6 +206,8 @@ struct class { struct pm_ops *pm; }; +extern struct kobject *sysfs_dev_block_kobj; +extern struct kobject *sysfs_dev_char_kobj; extern int __must_check class_register(struct class *class); extern void class_unregister(struct class *class); extern int class_for_each_device(struct class *class, void *data, |