rt2x00: Introduce concept of driver data in struct rt2x00_dev.

We are getting more and more fields in struct rt2x00_dev that are
specific to one or two of the low-level drivers. Instead of putting
these fields inside the main structure and thus clobbering all low-level
drivers with these fields, introduce the concept of driver data inside
struct rt2x00_dev, whose size is indicated by the low-level driver and
which can be populated by the low-level driver.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00.h

@@ -647,6 +647,7 @@ struct rt2x00lib_ops {
  */
 struct rt2x00_ops {
 	const char *name;
+	const unsigned int drv_data_size;
 	const unsigned int max_sta_intf;
 	const unsigned int max_ap_intf;
 	const unsigned int eeprom_size;
@@ -741,6 +742,11 @@ struct rt2x00_dev {
 	 */
 	const struct rt2x00_ops *ops;
 
+	/*
+	 * Driver data.
+	 */
+	void *drv_data;
+
 	/*
 	 * IEEE80211 control structure.
 	 */

drivers/net/wireless/rt2x00/rt2x00dev.c

@@ -1121,6 +1121,18 @@ int rt2x00lib_probe_dev(struct rt2x00_dev *rt2x00dev)
 {
 	int retval = -ENOMEM;
 
+	/*
+	 * Allocate the driver data memory, if necessary.
+	 */
+	if (rt2x00dev->ops->drv_data_size > 0) {
+		rt2x00dev->drv_data = kzalloc(rt2x00dev->ops->drv_data_size,
+			                      GFP_KERNEL);
+		if (!rt2x00dev->drv_data) {
+			retval = -ENOMEM;
+			goto exit;
+		}
+	}
+
 	spin_lock_init(&rt2x00dev->irqmask_lock);
 	mutex_init(&rt2x00dev->csr_mutex);
 
@@ -1261,6 +1273,12 @@ void rt2x00lib_remove_dev(struct rt2x00_dev *rt2x00dev)
 	 * Free queue structures.
 	 */
 	rt2x00queue_free(rt2x00dev);
+
+	/*
+	 * Free the driver data.
+	 */
+	if (rt2x00dev->drv_data)
+		kfree(rt2x00dev->drv_data);
 }
 EXPORT_SYMBOL_GPL(rt2x00lib_remove_dev);