[PATCH] Driver core: add generic "subsystem" link to all devices

Like the SUBSYTEM= key we find in the environment of the uevent, this
creates a generic "subsystem" link in sysfs for every device. Userspace
usually doesn't care at all if its a "class" or a "bus" device. This
provides an unified way to determine the subsytem of a device, regardless
of the way the driver core has created it.

Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 50e841a33af0..9aa127460262 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -561,6 +561,7 @@ int class_device_add(struct class_device *class_dev)
                 goto out2;
 
         /* add the needed attributes to this device */
+        sysfs_create_link(&class_dev->kobj, &parent_class->subsys.kset.kobj, "subsystem");
         class_dev->uevent_attr.attr.name = "uevent";
         class_dev->uevent_attr.attr.mode = S_IWUSR;
         class_dev->uevent_attr.attr.owner = parent_class->owner;
@@ -737,6 +738,7 @@ void class_device_del(struct class_device *class_dev)
                 sysfs_remove_link(&class_dev->kobj, "device");
                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
         }
+        sysfs_remove_link(&class_dev->kobj, "subsystem");
         class_device_remove_file(class_dev, &class_dev->uevent_attr);
         if (class_dev->devt_attr)
                 class_device_remove_file(class_dev, class_dev->devt_attr);