Re: [Qemu-devel] [PATCH 4/5] virtio-blk: Drop bounce buffer from dataplane code

[Paolo Bonzini <pbonzini@redhat.com>]

Il 03/06/2014 14:52, Fam Zheng ha scritto:
> The block layer will handle the unaligned request.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  hw/block/dataplane/virtio-blk.c | 23 -----------------------
>  include/hw/virtio/virtio-blk.h  |  2 --
>  2 files changed, 25 deletions(-)
>
> diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
> index 968f824..b88eee9 100644
> --- a/hw/block/dataplane/virtio-blk.c
> +++ b/hw/block/dataplane/virtio-blk.c
> @@ -75,14 +75,6 @@ static void complete_rdwr(void *opaque, int ret)
>
>      trace_virtio_blk_data_plane_complete_request(req->s, req->elem->index, ret);
>
> -    if (req->read && req->bounce_iov.iov_base) {
> -        qemu_iovec_from_buf(&req->qiov, 0, req->bounce_iov.iov_base, len);
> -    }
> -
> -    if (req->bounce_iov.iov_base) {
> -        qemu_vfree(req->bounce_iov.iov_base);
> -    }
> -
>      qemu_iovec_from_buf(req->inhdr, 0, &hdr, sizeof(hdr));
>      qemu_iovec_destroy(req->inhdr);
>      g_slice_free(QEMUIOVector, req->inhdr);
> @@ -142,21 +134,6 @@ static void do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
>
>      qiov = &req->qiov;
>
> -    if (!bdrv_qiov_is_aligned(s->blk->conf.bs, qiov)) {
> -        void *bounce_buffer = qemu_blockalign(s->blk->conf.bs, qiov->size);
> -
> -        /* Populate bounce buffer with data for writes */
> -        if (!read) {
> -            qemu_iovec_to_buf(qiov, 0, bounce_buffer, qiov->size);
> -        }
> -
> -        /* Redirect I/O to aligned bounce buffer */
> -        req->bounce_iov.iov_base = bounce_buffer;
> -        req->bounce_iov.iov_len = qiov->size;
> -        qemu_iovec_init_external(&req->bounce_qiov, &req->bounce_iov, 1);
> -        qiov = &req->bounce_qiov;
> -    }
> -
>      nb_sectors = qiov->size / BDRV_SECTOR_SIZE;
>
>      if (read) {
> diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
> index d9ff1c9..e406efa 100644
> --- a/include/hw/virtio/virtio-blk.h
> +++ b/include/hw/virtio/virtio-blk.h
> @@ -146,8 +146,6 @@ typedef struct VirtIOBlockReq {
>  #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
>      struct VirtIOBlockDataPlane *s;
>      QEMUIOVector *inhdr;            /* iovecs for virtio_blk_inhdr */
> -    struct iovec bounce_iov;        /* used if guest buffers are unaligned */
> -    QEMUIOVector bounce_qiov;       /* bounce buffer iovecs */
>      bool read;                      /* read or write? */
>  #endif
>  } VirtIOBlockReq;
>

Can you move this before patch 3?

Paolo