virtio-blk: Make request completion function virtual

virtio_blk_req_complete will call VirtIOBlock.complete_request() to push
data and notify guest. No functional change.

Later, this will allow dataplane to provide it's own (vring_) version.

Signed-off-by: Fam Zheng <famz@redhat.com>
Tested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

hw/block/virtio-blk.c

@@ -44,7 +44,8 @@ static void virtio_blk_free_request(VirtIOBlockReq *req)
     }
 }
 
-static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
+static void virtio_blk_complete_request(VirtIOBlockReq *req,
+                                        unsigned char status)
 {
     VirtIOBlock *s = req->dev;
     VirtIODevice *vdev = VIRTIO_DEVICE(s);
@@ -56,6 +57,11 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
     virtio_notify(vdev, s->vq);
 }
 
+static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status)
+{
+    req->dev->complete_request(req, status);
+}
+
 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
     bool is_read)
 {
@@ -740,6 +746,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
     s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
 
     s->vq = virtio_add_queue(vdev, 128, virtio_blk_handle_output);
+    s->complete_request = virtio_blk_complete_request;
 #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
     virtio_blk_data_plane_create(vdev, blk, &s->dataplane, &err);
     if (err != NULL) {

include/hw/virtio/virtio-blk.h

@@ -117,6 +117,7 @@ struct VirtIOBlkConf
 
 struct VirtIOBlockDataPlane;
 
+struct VirtIOBlockReq;
 typedef struct VirtIOBlock {
     VirtIODevice parent_obj;
     BlockDriverState *bs;
@@ -128,6 +129,8 @@ typedef struct VirtIOBlock {
     unsigned short sector_mask;
     bool original_wce;
     VMChangeStateEntry *change;
+    /* Function to push to vq and notify guest */
+    void (*complete_request)(struct VirtIOBlockReq *req, unsigned char status);
 #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
     Notifier migration_state_notifier;
     struct VirtIOBlockDataPlane *dataplane;