On Thu, 2014-05-01 at 16:51 +0200, Christoph Hellwig wrote:
> Taken almost entirely from Nicholas Bellinger's scsi-mq conversion.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
Reviewed-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> drivers/scsi/virtio_scsi.c | 25 +++++++------------------
> include/scsi/scsi_cmnd.h | 9 +++++++++
> 2 files changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index 16bfd50..5ec4a73 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -204,7 +204,6 @@ static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf)
> set_driver_byte(sc, DRIVER_SENSE);
> }
>
> - mempool_free(cmd, virtscsi_cmd_pool);
> sc->scsi_done(sc);
>
> atomic_dec(&tgt->reqs);
> @@ -279,8 +278,6 @@ static void virtscsi_complete_free(struct virtio_scsi *vscsi, void *buf)
>
> if (cmd->comp)
> complete_all(cmd->comp);
> - else
> - mempool_free(cmd, virtscsi_cmd_pool);
> }
>
> static void virtscsi_ctrl_done(struct virtqueue *vq)
> @@ -496,10 +493,9 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
> struct virtio_scsi_vq *req_vq,
> struct scsi_cmnd *sc)
> {
> - struct virtio_scsi_cmd *cmd;
> - int ret;
> -
> struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
> + struct virtio_scsi_cmd *cmd = scsi_cmd_priv(sc);
> +
> BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
>
> /* TODO: check feature bit and fail if unsupported? */
> @@ -508,11 +504,6 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
> dev_dbg(&sc->device->sdev_gendev,
> "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]);
>
> - ret = SCSI_MLQUEUE_HOST_BUSY;
> - cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
> - if (!cmd)
> - goto out;
> -
> memset(cmd, 0, sizeof(*cmd));
> cmd->sc = sc;
> cmd->req.cmd = (struct virtio_scsi_cmd_req){
> @@ -531,13 +522,9 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
>
> if (virtscsi_kick_cmd(req_vq, cmd,
> sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
> - GFP_ATOMIC) == 0)
> - ret = 0;
> - else
> - mempool_free(cmd, virtscsi_cmd_pool);
> -
> -out:
> - return ret;
> + GFP_ATOMIC) != 0)
> + return SCSI_MLQUEUE_HOST_BUSY;
> + return 0;
> }
>
> static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
> @@ -683,6 +670,7 @@ static struct scsi_host_template virtscsi_host_template_single = {
> .name = "Virtio SCSI HBA",
> .proc_name = "virtio_scsi",
> .this_id = -1,
> + .cmd_size = sizeof(struct virtio_scsi_cmd),
> .queuecommand = virtscsi_queuecommand_single,
> .eh_abort_handler = virtscsi_abort,
> .eh_device_reset_handler = virtscsi_device_reset,
> @@ -699,6 +687,7 @@ static struct scsi_host_template virtscsi_host_template_multi = {
> .name = "Virtio SCSI HBA",
> .proc_name = "virtio_scsi",
> .this_id = -1,
> + .cmd_size = sizeof(struct virtio_scsi_cmd),
> .queuecommand = virtscsi_queuecommand_multi,
> .eh_abort_handler = virtscsi_abort,
> .eh_device_reset_handler = virtscsi_device_reset,
> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
> index dd7c998..e016e2a 100644
> --- a/include/scsi/scsi_cmnd.h
> +++ b/include/scsi/scsi_cmnd.h
> @@ -133,6 +133,15 @@ struct scsi_cmnd {
> unsigned char tag; /* SCSI-II queued command tag */
> };
>
> +/*
> + * Return the driver private allocation behind the command.
> + * Only works if cmd_size is set in the host template.
> + */
> +static inline void *scsi_cmd_priv(struct scsi_cmnd *cmd)
> +{
> + return cmd + 1;
> +}
> +
> /* make sure not to use it with REQ_TYPE_BLOCK_PC commands */
> static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
> {
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