On Tue, Aug 21, 2012 at 9:26 AM, Cong Meng <mc@xxxxxxxxxxxxxxxxxx> wrote:
> Each virtio scsi HBA has global request queue limits. But the passthrough
> LUNs (scsi-generic) come from different host HBAs may have different request
> queue limits. If the guest sends commands that exceed the host limits, the
> commands will be rejected by host HAB.
>
> This patch addresses this issue by getting the per-LUN queue limits via the the
> newly added virtio control request, then setting them properly.
>
> Signed-off-by: Cong Meng <mc@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/scsi/virtio_scsi.c | 113 +++++++++++++++++++++++++++++++++++++------
> include/linux/virtio_scsi.h | 18 +++++++
> 2 files changed, 116 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index 173cb39..ec5066f 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -35,12 +35,14 @@ struct virtio_scsi_cmd {
> struct virtio_scsi_cmd_req cmd;
> struct virtio_scsi_ctrl_tmf_req tmf;
> struct virtio_scsi_ctrl_an_req an;
> + struct virtio_scsi_ctrl_lq_req lq;
> } req;
> union {
> struct virtio_scsi_cmd_resp cmd;
> struct virtio_scsi_ctrl_tmf_resp tmf;
> struct virtio_scsi_ctrl_an_resp an;
> struct virtio_scsi_event evt;
> + struct virtio_scsi_ctrl_lq_resp lq;
> } resp;
> } ____cacheline_aligned_in_smp;
>
> @@ -469,6 +471,46 @@ out:
> return ret;
> }
>
> +static u32 virtscsi_lun_query(struct scsi_device *sdev, u32 *value, u32 subtype)
> +{
> + struct Scsi_Host *shost = sdev->host;
> + struct virtio_scsi *vscsi = shost_priv(shost);
> + DECLARE_COMPLETION_ONSTACK(comp);
> + struct virtio_scsi_cmd *cmd;
> + struct virtio_scsi_target_state *tgt = vscsi->tgt[sdev->id];
> + unsigned int ret = VIRTIO_SCSI_S_FAILURE;
> +
> + cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC);
> + if (!cmd)
> + goto out;
> +
> + memset(cmd, 0, sizeof(*cmd));
> + cmd->comp = ∁
> + cmd->req.lq = (struct virtio_scsi_ctrl_lq_req){
> + .type = VIRTIO_SCSI_T_LUN_QUERY,
> + .subtype = subtype,
> + .lun[0] = 1,
> + .lun[1] = sdev->id,
> + .lun[2] = (sdev->lun >> 8) | 0x40,
> + .lun[3] = sdev->lun & 0xff,
The LUN addressing code has been duplicated several times now. How
about replacing it with something like
static void virtio_scsi_set_lun(u8 *lun, struct scsi_device *sdev)
{
lun[0] = 1;
lun[1] = sdev->id;
lun[2] = (sdev->lun >> 8) | 0x40;
lun[3] = sdev->lun & 0xff;
lun[4] = lun[5] = lun[6] = lun[7] = 0;
}
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