driver model: add per-class rwsem and protect list accesses with it.

This is similar to struct bus_type's rwsem, though classes aren't doing 
anything nearly as fancy with it. We just make sure to take it when ever
we add or remove any devices or drivers. 

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index c0f8d6c5e4bf..fdcdf0077027 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -163,6 +163,8 @@ extern void driver_remove_file(struct device_driver *, struct driver_attribute *
  */
 struct device_class {
 	char			* name;
+	struct rw_semaphore	rwsem;
+
 	atomic_t		refcount;
 	u32			present;