block: Convert bdrv_lock_medium() to co_wrapper

bdrv_lock_medium() is categorized as an I/O function, and it currently
doesn't run in a coroutine. We should let it take a graph rdlock since
it traverses the block nodes graph, which however is only possible in a
coroutine.

The only caller of this function is blk_lock_medium(). Therefore make
blk_lock_medium() a co_wrapper, so that it always creates a new
coroutine, and then make bdrv_lock_medium() a coroutine_fn where the
lock can be taken.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230113204212.359076-13-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h
index 3db103087c..b1196ab93c 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -59,7 +59,9 @@ bool coroutine_fn blk_co_is_inserted(BlockBackend *blk);
 bool co_wrapper_mixed blk_is_inserted(BlockBackend *blk);
 
 bool blk_is_available(BlockBackend *blk);
-void blk_lock_medium(BlockBackend *blk, bool locked);
+
+void coroutine_fn blk_co_lock_medium(BlockBackend *blk, bool locked);
+void co_wrapper blk_lock_medium(BlockBackend *blk, bool locked);
 
 void coroutine_fn blk_co_eject(BlockBackend *blk, bool eject_flag);
 void co_wrapper blk_eject(BlockBackend *blk, bool eject_flag);