[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/bus.c b/drivers/base/bus.c
index 64ba9011d1a8..050d86d0b872 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -374,6 +374,7 @@ int bus_add_device(struct device * dev)
                 error = device_add_attrs(bus, dev);
                 if (!error) {
                         sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
+                        sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "subsystem");
                         sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus");
                 }
         }
@@ -408,6 +409,7 @@ void bus_attach_device(struct device * dev)
 void bus_remove_device(struct device * dev)
 {
         if (dev->bus) {
+                sysfs_remove_link(&dev->kobj, "subsystem");
                 sysfs_remove_link(&dev->kobj, "bus");
                 sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
                 device_remove_attrs(dev->bus, dev);