Re: [PATCH V1] virtio_scsi: support multi hw queue of blk-mq

[Paolo Bonzini <pbonzini@redhat.com>]

On 15/11/2014 04:47, Ming Lei wrote:
> Since virtio_scsi has supported multi virtqueue already,
> it is natural to map the virtque to hw-queue of blk-mq.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Ming Lei <ming.lei@canonical.com>
> ---
> V1:
> 	- support non-mq too
> 
>  drivers/scsi/virtio_scsi.c |   17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index b83846f..d3af70e 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -561,6 +561,15 @@ static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
>  	return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc);
>  }
>  
> +static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
> +						  struct scsi_cmnd *sc)
> +{
> +	u32 tag = blk_mq_unique_tag(sc->request);
> +	u16 hwq = blk_mq_unique_tag_to_hwq(tag);
> +
> +	return &vscsi->req_vqs[hwq];
> +}
> +
>  static struct virtio_scsi_vq *virtscsi_pick_vq(struct virtio_scsi *vscsi,
>  					       struct virtio_scsi_target_state *tgt)
>  {
> @@ -604,7 +613,12 @@ static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
>  	struct virtio_scsi *vscsi = shost_priv(sh);
>  	struct virtio_scsi_target_state *tgt =
>  				scsi_target(sc->device)->hostdata;
> -	struct virtio_scsi_vq *req_vq = virtscsi_pick_vq(vscsi, tgt);
> +	struct virtio_scsi_vq *req_vq;
> +
> +	if (shost_use_blk_mq(sh))
> +		req_vq = virtscsi_pick_vq_mq(vscsi, sc);
> +	else
> +		req_vq = virtscsi_pick_vq(vscsi, tgt);
>  
>  	return virtscsi_queuecommand(vscsi, req_vq, sc);
>  }
> @@ -983,6 +997,7 @@ static int virtscsi_probe(struct virtio_device *vdev)
>  	shost->max_id = num_targets;
>  	shost->max_channel = 0;
>  	shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
> +	shost->nr_hw_queues = num_queues;
>  
>  	if (virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
>  		host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>