block: Add refcnt in BlockDriverAIOCB

This will be useful in synchronous cancel emulation with
bdrv_aio_cancel_async.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/block/aio.h b/include/block/aio.h
index 4603c0f066..2626fc745f 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -35,11 +35,13 @@ struct BlockDriverAIOCB {
     BlockDriverState *bs;
     BlockDriverCompletionFunc *cb;
     void *opaque;
+    int refcnt;
 };
 
 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
                    BlockDriverCompletionFunc *cb, void *opaque);
 void qemu_aio_release(void *p);
+void qemu_aio_ref(void *p);
 
 typedef struct AioHandler AioHandler;
 typedef void QEMUBHFunc(void *opaque);