[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, 7 insertions, 2 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 252cf403f891..cc8bb97427d0 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -319,9 +319,12 @@ int device_add(struct device *dev)
                 dev->devt_attr = attr;
         }
 
-        if (dev->class)
+        if (dev->class) {
+                sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
+                                  "subsystem");
                 sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
                                   dev->bus_id);
+        }
 
         if ((error = device_pm_add(dev)))
                 goto PMError;
@@ -422,8 +425,10 @@ void device_del(struct device * dev)
                 klist_del(&dev->knode_parent);
         if (dev->devt_attr)
                 device_remove_file(dev, dev->devt_attr);
-        if (dev->class)
+        if (dev->class) {
+                sysfs_remove_link(&dev->kobj, "subsystem");
                 sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
+        }
         device_remove_file(dev, &dev->uevent_attr);
 
         /* Notify the platform of the removal, in case they