Re: [Qemu-devel] [PATCH v2 8/8] virtio-blk: Fill in VirtIOBlockReq.out in dataplane code

[Paolo Bonzini <pbonzini@redhat.com>]

Il 05/06/2014 03:58, Fam Zheng ha scritto:
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  hw/block/dataplane/virtio-blk.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
> index 96068cd..323793a 100644
> --- a/hw/block/dataplane/virtio-blk.c
> +++ b/hw/block/dataplane/virtio-blk.c
> @@ -113,7 +113,8 @@ static void do_get_id_cmd(VirtIOBlockDataPlane *s,
>  static void do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
>                          struct iovec *iov, unsigned iov_cnt,
>                          int64_t sector_num, VirtQueueElement *elem,
> -                        struct virtio_blk_inhdr *inhdr)
> +                        struct virtio_blk_inhdr *inhdr,
> +                        struct virtio_blk_outhdr *outhdr)
>  {
>      VirtIOBlock *dev = VIRTIO_BLK(s->vdev);
>      VirtIOBlockReq *req = g_slice_new0(VirtIOBlockReq);
> @@ -124,6 +125,7 @@ static void do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
>      req->elem = elem;
>      req->dev = dev;
>      req->in = inhdr;
> +    req->out = *outhdr;
>      qemu_iovec_init_external(&req->qiov, iov, iov_cnt);
>
>      qiov = &req->qiov;
> @@ -155,13 +157,15 @@ static void complete_flush(void *opaque, int ret)
>  }
>
>  static void do_flush_cmd(VirtIOBlockDataPlane *s, VirtQueueElement *elem,
> -                         struct virtio_blk_inhdr *inhdr)
> +                         struct virtio_blk_inhdr *inhdr,
> +                         struct virtio_blk_outhdr *outhdr)
>  {
>      VirtIOBlock *dev = VIRTIO_BLK(s->vdev);
>      VirtIOBlockReq *req = g_slice_new0(VirtIOBlockReq);
>      req->dev = dev;
>      req->elem = elem;
>      req->in = inhdr;
> +    req->out = *outhdr;
>
>      bdrv_aio_flush(s->blk->conf.bs, complete_flush, req);
>  }
> @@ -202,13 +206,13 @@ static int process_request(VirtIOBlockDataPlane *s, VirtQueueElement *elem)
>      case VIRTIO_BLK_T_IN:
>          do_rdwr_cmd(s, true, in_iov, in_num,
>                      outhdr.sector * 512 / BDRV_SECTOR_SIZE,
> -                    elem, inhdr);
> +                    elem, inhdr, &outhdr);
>          return 0;
>
>      case VIRTIO_BLK_T_OUT:
>          do_rdwr_cmd(s, false, iov, out_num,
>                      outhdr.sector * 512 / BDRV_SECTOR_SIZE,
> -                    elem, inhdr);
> +                    elem, inhdr, &outhdr);
>          return 0;
>
>      case VIRTIO_BLK_T_SCSI_CMD:
> @@ -216,7 +220,7 @@ static int process_request(VirtIOBlockDataPlane *s, VirtQueueElement *elem)
>          return 0;
>
>      case VIRTIO_BLK_T_FLUSH:
> -        do_flush_cmd(s, elem, inhdr);
> +        do_flush_cmd(s, elem, inhdr, &outhdr);
>          return 0;
>
>      case VIRTIO_BLK_T_GET_ID:
>

Can you try moving the req allocation and assignments inside 
process_request instead?  Then you can fill in req->out directly without 
the struct assignment.

Paolo