sysfs: Add attribute array to sysdev classes

Add a attribute array that is automatically registered and unregistered
to struct sysdev_class. This is similar to what struct class has.

A lot of drivers add list of attributes, so it's better to do 
this easily in the common sysdev layer.

This adds a new field to struct sysdev_class. I audited the 
whole tree and there are no dynamically allocated sysdev classes,
so this is fully compatible. 

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 10 insertions, 1 deletions

diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index a38445c0f8c5..747c99e0568b 100644
--- a/drivers/base/sys.c
+++ b/drivers/base/sys.c
@@ -145,13 +145,20 @@ int sysdev_class_register(struct sysdev_class *cls)
         if (retval)
                 return retval;
 
-        return kset_register(&cls->kset);
+        retval = kset_register(&cls->kset);
+        if (!retval && cls->attrs)
+                retval = sysfs_create_files(&cls->kset.kobj,
+                                            (const struct attribute **)cls->attrs);
+        return retval;
 }
 
 void sysdev_class_unregister(struct sysdev_class *cls)
 {
         pr_debug("Unregistering sysdev class '%s'\n",
                  kobject_name(&cls->kset.kobj));
+        if (cls->attrs)
+                sysfs_remove_files(&cls->kset.kobj,
+                                   (const struct attribute **)cls->attrs);
         kset_unregister(&cls->kset);
 }
 
diff --git a/include/linux/sysdev.h b/include/linux/sysdev.h
index c2458fa8376c..b6244f9b533f 100644
--- a/include/linux/sysdev.h
+++ b/include/linux/sysdev.h
@@ -27,10 +27,12 @@
 
 
 struct sys_device;
+struct sysdev_class_attribute;
 
 struct sysdev_class {
         const char *name;
         struct list_head        drivers;
+        struct sysdev_class_attribute **attrs;
 
         /* Default operations for these types of devices */
         int     (*shutdown)(struct sys_device *);