Commit 1dc936aa authored by Fam Zheng's avatar Fam Zheng Committed by Kevin Wolf
Browse files

virtio-blk: Use blk_aio_ioctl 



Use the asynchronous interface of ioctl. This will not make the VM
unresponsive if the ioctl takes a long time.

Signed-off-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 75344fa4

hw/block/virtio-blk.c

+79 −46
Original line number Diff line number Diff line
@@ -115,6 +115,56 @@ static void virtio_blk_flush_complete(void *opaque, int ret) 
    virtio_blk_free_request(req);

}



#ifdef __linux__



typedef struct {

    VirtIOBlockReq *req;

    struct sg_io_hdr hdr;

} VirtIOBlockIoctlReq;



static void virtio_blk_ioctl_complete(void *opaque, int status)

{

    VirtIOBlockIoctlReq *ioctl_req = opaque;

    VirtIOBlockReq *req = ioctl_req->req;

    VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);

    struct virtio_scsi_inhdr *scsi;

    struct sg_io_hdr *hdr;



    scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;



    if (status) {

        status = VIRTIO_BLK_S_UNSUPP;

        virtio_stl_p(vdev, &scsi->errors, 255);

        goto out;

    }



    hdr = &ioctl_req->hdr;

    /*

     * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)

     * clear the masked_status field [hence status gets cleared too, see

     * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED

     * status has occurred.  However they do set DRIVER_SENSE in driver_status

     * field. Also a (sb_len_wr > 0) indicates there is a sense buffer.

     */

    if (hdr->status == 0 && hdr->sb_len_wr > 0) {

        hdr->status = CHECK_CONDITION;

    }



    virtio_stl_p(vdev, &scsi->errors,

                 hdr->status | (hdr->msg_status << 8) |

                 (hdr->host_status << 16) | (hdr->driver_status << 24));

    virtio_stl_p(vdev, &scsi->residual, hdr->resid);

    virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr);

    virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len);



out:

    virtio_blk_req_complete(req, status);

    virtio_blk_free_request(req);

    g_free(ioctl_req);

}



#endif



static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)

{

    VirtIOBlockReq *req = virtio_blk_alloc_request(s);
@@ -137,7 +187,7 @@ static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req) 


#ifdef __linux__

    int i;

    struct sg_io_hdr hdr;

    VirtIOBlockIoctlReq *ioctl_req;

#endif



    /*
@@ -172,71 +222,52 @@ static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req) 
    }



#ifdef __linux__

    memset(&hdr, 0, sizeof(struct sg_io_hdr));

    hdr.interface_id = 'S';

    hdr.cmd_len = elem->out_sg[1].iov_len;

    hdr.cmdp = elem->out_sg[1].iov_base;

    hdr.dxfer_len = 0;

    ioctl_req = g_new0(VirtIOBlockIoctlReq, 1);

    ioctl_req->req = req;

    ioctl_req->hdr.interface_id = 'S';

    ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len;

    ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base;

    ioctl_req->hdr.dxfer_len = 0;



    if (elem->out_num > 2) {

        /*

         * If there are more than the minimally required 2 output segments

         * there is write payload starting from the third iovec.

         */

        hdr.dxfer_direction = SG_DXFER_TO_DEV;

        hdr.iovec_count = elem->out_num - 2;

        ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV;

        ioctl_req->hdr.iovec_count = elem->out_num - 2;



        for (i = 0; i < hdr.iovec_count; i++)

            hdr.dxfer_len += elem->out_sg[i + 2].iov_len;

        for (i = 0; i < ioctl_req->hdr.iovec_count; i++) {

            ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len;

        }



        hdr.dxferp = elem->out_sg + 2;

        ioctl_req->hdr.dxferp = elem->out_sg + 2;



    } else if (elem->in_num > 3) {

        /*

         * If we have more than 3 input segments the guest wants to actually

         * read data.

         */

        hdr.dxfer_direction = SG_DXFER_FROM_DEV;

        hdr.iovec_count = elem->in_num - 3;

        for (i = 0; i < hdr.iovec_count; i++)

            hdr.dxfer_len += elem->in_sg[i].iov_len;

        ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV;

        ioctl_req->hdr.iovec_count = elem->in_num - 3;

        for (i = 0; i < ioctl_req->hdr.iovec_count; i++) {

            ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len;

        }



        hdr.dxferp = elem->in_sg;

        ioctl_req->hdr.dxferp = elem->in_sg;

    } else {

        /*

         * Some SCSI commands don't actually transfer any data.

         */

        hdr.dxfer_direction = SG_DXFER_NONE;

    }



    hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base;

    hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len;



    status = blk_ioctl(blk->blk, SG_IO, &hdr);

    if (status) {

        status = VIRTIO_BLK_S_UNSUPP;

        goto fail;

    }



    /*

     * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)

     * clear the masked_status field [hence status gets cleared too, see

     * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED

     * status has occurred.  However they do set DRIVER_SENSE in driver_status

     * field. Also a (sb_len_wr > 0) indicates there is a sense buffer.

     */

    if (hdr.status == 0 && hdr.sb_len_wr > 0) {

        hdr.status = CHECK_CONDITION;

        ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE;

    }



    virtio_stl_p(vdev, &scsi->errors,

                 hdr.status | (hdr.msg_status << 8) |

                 (hdr.host_status << 16) | (hdr.driver_status << 24));

    virtio_stl_p(vdev, &scsi->residual, hdr.resid);

    virtio_stl_p(vdev, &scsi->sense_len, hdr.sb_len_wr);

    virtio_stl_p(vdev, &scsi->data_len, hdr.dxfer_len);

    ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base;

    ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len;



    return status;

    blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr,

                  virtio_blk_ioctl_complete, ioctl_req);

    return -EINPROGRESS;

#else

    abort();

#endif
@@ -254,9 +285,11 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req) 
    int status;



    status = virtio_blk_handle_scsi_req(req);

    if (status != -EINPROGRESS) {

        virtio_blk_req_complete(req, status);

        virtio_blk_free_request(req);

    }

}



void virtio_submit_multiwrite(BlockBackend *blk, MultiReqBuffer *mrb)

{