Hi Sagi,
Thanks. I will try to test the patch sometime this week. Sorry about the delay.
Thanks
-Karan
On Tue, 2018-06-19 at 17:59 +0300, Sagi Grimberg wrote:
> > Hi,
>
> Hi Karan,
>
> > I have run in to a problem where it seems like an ISER initiator cannot
> > submit more than 128 commands to the target (per scsi host). I tried to
> > debug this and found that when iscsi_host_add() is called,
> > Scsi_Host>can_queue is unset. This causes iscsi_host_add() to use the
> > default qdepth (128) when creating the scsi host's blk-mq in
> > scsi_add_host(). After the call to iscsi_host_add() shost->can_queue is
> > set to the correct value, however by then the blk-mq is already created
> > with the wrong nuber of tags.
> >
> > This causes the queue depth not to exceed 128.
> >
> > Please advise if this is the expected behaviour. Have I missed
> > something? It appears that other drivers that call scsi_add_host() set
> > can_queue before the function call.
>
> Thanks for reporting, you are correct, this can be easily fixed, does
> the below patch fix your issue:
> --
> diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c
> b/drivers/infiniband/ulp/iser/iscsi_iser.c
> index 0336643c2ed6..434ae88ff623 100644
> --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
> +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
> @@ -633,8 +633,8 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
> */
> if (ep) {
> iser_conn = ep->dd_data;
> - max_cmds = iser_conn->max_cmds;
> shost->sg_tablesize = iser_conn->scsi_sg_tablesize;
> + shost->can_queue = min_t(u16, cmds_max,
> iser_conn->max_cmds);
>
> mutex_lock(&iser_conn->state_mutex);
> if (iser_conn->state != ISER_CONN_UP) {
> @@ -660,6 +660,7 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
> }
> mutex_unlock(&iser_conn->state_mutex);
> } else {
> + shost->can_queue = min_t(u16, cmds_max,
> ISER_DEF_XMIT_CMDS_MAX);
> max_cmds = ISER_DEF_XMIT_CMDS_MAX;
> if (iscsi_host_add(shost, NULL))
> goto free_host;
> @@ -678,12 +679,6 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
> iser_conn, shost->sg_tablesize,
> shost->max_sectors);
>
> - if (cmds_max > max_cmds) {
> - iser_info("cmds_max changed from %u to %u\n",
> - cmds_max, max_cmds);
> - cmds_max = max_cmds;
> - }
> -
> cls_session = iscsi_session_setup(&iscsi_iser_transport, shost,
> cmds_max, 0,
> sizeof(struct iscsi_iser_task),
> @@ -692,7 +687,6 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
> goto remove_host;
> session = cls_session->dd_data;
>
> - shost->can_queue = session->scsi_cmds_max;
> return cls_session;
>
> remove_host:
> --
--
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