block: Convert bdrv_eject() to co_wrapper

bdrv_eject() 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_eject(). Therefore make
blk_eject() a co_wrapper, so that it always creates a new coroutine, and
then make bdrv_eject() 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: <20230113204212.359076-12-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 46c7e57..61ece82 100644
--- a/block.c
+++ b/block.c
@@ -6821,13 +6821,13 @@
 /**
  * If eject_flag is TRUE, eject the media. Otherwise, close the tray
  */
-void bdrv_eject(BlockDriverState *bs, bool eject_flag)
+void coroutine_fn bdrv_co_eject(BlockDriverState *bs, bool eject_flag)
 {
     BlockDriver *drv = bs->drv;
     IO_CODE();
 
-    if (drv && drv->bdrv_eject) {
-        drv->bdrv_eject(bs, eject_flag);
+    if (drv && drv->bdrv_co_eject) {
+        drv->bdrv_co_eject(bs, eject_flag);
     }
 }