block: Convert bdrv_io_plug() to co_wrapper

BlockDriver->bdrv_io_plug is categorized as IO callback, and it
currently doesn't run in a coroutine. We should let it take a graph
rdlock since the callback traverses the block nodes graph, which however
is only possible in a coroutine.

The only caller of this function is blk_io_plug(), therefore make
blk_io_plug() a co_wrapper, so that we're always running in a coroutine
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: <20230113204212.359076-3-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/block/io.c b/block/io.c
index a09a19f..00bab27 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3137,19 +3137,19 @@ void *qemu_try_blockalign0(BlockDriverState *bs, size_t size)
     return mem;
 }
 
-void bdrv_io_plug(BlockDriverState *bs)
+void coroutine_fn bdrv_co_io_plug(BlockDriverState *bs)
 {
     BdrvChild *child;
     IO_CODE();
 
     QLIST_FOREACH(child, &bs->children, next) {
-        bdrv_io_plug(child->bs);
+        bdrv_co_io_plug(child->bs);
     }
 
     if (qatomic_fetch_inc(&bs->io_plugged) == 0) {
         BlockDriver *drv = bs->drv;
-        if (drv && drv->bdrv_io_plug) {
-            drv->bdrv_io_plug(bs);
+        if (drv && drv->bdrv_co_io_plug) {
+            drv->bdrv_co_io_plug(bs);
         }
     }
 }