[CLASS DEVICE]: add attribute_group creation

Extend the support of attribute groups in class_device's to allow
groups to be created as part of the registration process. This allows
network device's to avoid race between registration and creating
groups.

Note that unlike attributes that are a property of the class object,
the groups are a property of the class_device object. This is done
because there are different types of network devices (wireless for
example).

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 34 insertions, 0 deletions

diff --git a/drivers/base/class.c b/drivers/base/class.c
index 0e71dff327cd..b1ea4df85c7d 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -456,6 +456,35 @@ static void class_device_remove_attrs(struct class_device * cd)
         }
 }
 
+static int class_device_add_groups(struct class_device * cd)
+{
+        int i;
+        int error = 0;
+
+        if (cd->groups) {
+                for (i = 0; cd->groups[i]; i++) {
+                        error = sysfs_create_group(&cd->kobj, cd->groups[i]);
+                        if (error) {
+                                while (--i >= 0)
+                                        sysfs_remove_group(&cd->kobj, cd->groups[i]);
+                                goto out;
+                        }
+                }
+        }
+out:
+        return error;
+}
+
+static void class_device_remove_groups(struct class_device * cd)
+{
+        int i;
+        if (cd->groups) {
+                for (i = 0; cd->groups[i]; i++) {
+                        sysfs_remove_group(&cd->kobj, cd->groups[i]);
+                }
+        }
+}
+
 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 {
         return print_dev_t(buf, class_dev->devt);
@@ -559,6 +588,8 @@ int class_device_add(struct class_device *class_dev)
                                   class_name);
         }
 
+        class_device_add_groups(class_dev);
+
         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 
         /* notify any interfaces this device is now here */
@@ -672,6 +703,7 @@ void class_device_del(struct class_device *class_dev)
         if (class_dev->devt_attr)
                 class_device_remove_file(class_dev, class_dev->devt_attr);
         class_device_remove_attrs(class_dev);
+        class_device_remove_groups(class_dev);
 
         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
         kobject_del(&class_dev->kobj);
diff --git a/include/linux/device.h b/include/linux/device.h
index f6e72a65a3f2..e8e53b9accc6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -200,6 +200,7 @@ extern int class_device_create_file(struct class_device *,
  * @node: for internal use by the driver core only.
  * @kobj: for internal use by the driver core only.
  * @devt_attr: for internal use by the driver core only.
+ * @groups: optional additional groups to be created
  * @dev: if set, a symlink to the struct device is created in the sysfs
  * directory for this struct class device.
  * @class_data: pointer to whatever you want to store here for this struct
@@ -228,6 +229,7 @@ struct class_device {
         struct device           * dev;          /* not necessary, but nice to have */
         void                    * class_data;   /* class-specific data */
         struct class_device     *parent;        /* parent of this child device, if there is one */
+        struct attribute_group  ** groups;      /* optional groups */
 
         void    (*release)(struct class_device *dev);
         int     (*uevent)(struct class_device *dev, char **envp,