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/file-posix.c b/block/file-posix.c
index c76ed7d..a223dba 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -3765,7 +3765,7 @@
     return ret == CDS_DISC_OK;
 }
 
-static void cdrom_eject(BlockDriverState *bs, bool eject_flag)
+static void coroutine_fn cdrom_co_eject(BlockDriverState *bs, bool eject_flag)
 {
     BDRVRawState *s = bs->opaque;
 
@@ -3823,7 +3823,7 @@
 
     /* removable device support */
     .bdrv_co_is_inserted    = cdrom_co_is_inserted,
-    .bdrv_eject         = cdrom_eject,
+    .bdrv_co_eject          = cdrom_co_eject,
     .bdrv_lock_medium   = cdrom_lock_medium,
 
     /* generic scsi device */
@@ -3886,7 +3886,7 @@
     return raw_co_getlength(bs) > 0;
 }
 
-static void cdrom_eject(BlockDriverState *bs, bool eject_flag)
+static void coroutine_fn cdrom_co_eject(BlockDriverState *bs, bool eject_flag)
 {
     BDRVRawState *s = bs->opaque;
 
@@ -3952,7 +3952,7 @@
 
     /* removable device support */
     .bdrv_co_is_inserted     = cdrom_co_is_inserted,
-    .bdrv_eject         = cdrom_eject,
+    .bdrv_co_eject           = cdrom_co_eject,
     .bdrv_lock_medium   = cdrom_lock_medium,
 };
 #endif /* __FreeBSD__ */