throttle: Remove throttle_group_lock/unlock()

The group throttling code was always meant to handle its locking
internally. However, bdrv_swap() was touching the ThrottleGroup
structure directly and therefore needed an API for that.

Now that bdrv_swap() no longer exists there's no need for the
throttle_group_lock() API anymore.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/throttle-groups.c

@@ -33,8 +33,7 @@
  * its own locking.
  *
  * This locking is however handled internally in this file, so it's
- * mostly transparent to outside users (but see the documentation in
- * throttle_groups_lock()).
+ * transparent to outside users.
  *
  * The whole ThrottleGroup structure is private and invisible to
  * outside users, that only use it through its ThrottleState.
@@ -468,34 +467,6 @@ void throttle_group_unregister_bs(BlockDriverState *bs)
     bs->throttle_state = NULL;
 }
 
-/* Acquire the lock of this throttling group.
- *
- * You won't normally need to use this. None of the functions from the
- * ThrottleGroup API require you to acquire the lock since all of them
- * deal with it internally.
- *
- * This should only be used in exceptional cases when you want to
- * access the protected fields of a BlockDriverState directly
- * (e.g. bdrv_swap()).
- *
- * @bs: a BlockDriverState that is member of the group
- */
-void throttle_group_lock(BlockDriverState *bs)
-{
-    ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
-    qemu_mutex_lock(&tg->lock);
-}
-
-/* Release the lock of this throttling group.
- *
- * See the comments in throttle_group_lock().
- */
-void throttle_group_unlock(BlockDriverState *bs)
-{
-    ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
-    qemu_mutex_unlock(&tg->lock);
-}
-
 static void throttle_groups_init(void)
 {
     qemu_mutex_init(&throttle_groups_lock);

include/block/throttle-groups.h

@@ -43,7 +43,4 @@ void coroutine_fn throttle_group_co_io_limits_intercept(BlockDriverState *bs,
                                                         unsigned int bytes,
                                                         bool is_write);
 
-void throttle_group_lock(BlockDriverState *bs);
-void throttle_group_unlock(BlockDriverState *bs);
-
 #endif