block: Clean up after deleting BHs

Commit 6a7ad299 ("Call qemu_bh_delete at bdrv_aio_bh_cb") deletes emulated
aio bottom halves to prevent endless accumulation.  However, it leaves a
stale ->bh pointer, which is then waited on when the aio is reused.

Zeroing the pointer fixes the issue, allowing vmdk format images to be used.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/block.c b/block.c
index aca5a6d282..cefbe77485 100644
--- a/block.c
+++ b/block.c
@@ -1374,6 +1374,7 @@ static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb)
 {
     BlockDriverAIOCBSync *acb = (BlockDriverAIOCBSync *)blockacb;
     qemu_bh_delete(acb->bh);
+    acb->bh = NULL;
     qemu_aio_release(acb);
 }
 
@@ -1391,6 +1392,7 @@ static void bdrv_aio_bh_cb(void *opaque)
     qemu_vfree(acb->bounce);
     acb->common.cb(acb->common.opaque, acb->ret);
     qemu_bh_delete(acb->bh);
+    acb->bh = NULL;
     qemu_aio_release(acb);
 }