HID: hidraw: fix a problem of memory leak in hidraw_release()

'struct hidraw_list' is a circular queue whose head can be smaller than
tail. Using 'list->tail != list->head' to release all memory that should
be released.

Fixes: a5623a2 ("HID: hidraw: fix memory leak in hidraw_release()")
Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

Author: Su Hui

drivers/hid/hidraw.c

@@ -357,8 +357,11 @@ static int hidraw_release(struct inode * inode, struct file * file)
 	down_write(&minors_rwsem);
 
 	spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
-	for (int i = list->tail; i < list->head; i++)
-		kfree(list->buffer[i].value);
+	while (list->tail != list->head) {
+		kfree(list->buffer[list->tail].value);
+		list->buffer[list->tail].value = NULL;
+		list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
+	}
 	list_del(&list->node);
 	spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
 	kfree(list);