[Qemu-devel] [PULL for-2.1 2/3] virtio-blk: data-plane: fix save/set .complete_request in start

[Stefan Hajnoczi <stefanha@redhat.com>]

From: Ming Lei <ming.lei@canonical.com>

The callback has to be saved and reset in virtio_blk_data_plane_start(),
otherwise dataplane's requests will be completed in qemu aio context.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/block/dataplane/virtio-blk.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 227bb15..e88862d 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -125,7 +125,6 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
                                   Error **errp)
 {
     VirtIOBlockDataPlane *s;
-    VirtIOBlock *vblk = VIRTIO_BLK(vdev);
     Error *local_err = NULL;
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
@@ -178,8 +177,6 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
     bdrv_op_block_all(blk->conf.bs, s->blocker);
 
     *dataplane = s;
-    s->saved_complete_request = vblk->complete_request;
-    vblk->complete_request = complete_request_vring;
 }
 
 /* Context: QEMU global mutex held */
@@ -201,6 +198,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
 {
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+    VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
     VirtQueue *vq;
 
     if (s->started) {
@@ -234,6 +232,9 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
     }
     s->host_notifier = *virtio_queue_get_host_notifier(vq);
 
+    s->saved_complete_request = vblk->complete_request;
+    vblk->complete_request = complete_request_vring;
+
     s->starting = false;
     s->started = true;
     trace_virtio_blk_data_plane_start(s);
-- 
1.9.3