Re: iSER multi-queue configuration

[Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>]

> Hi Sagi,

Hi Ming,

> I'm looking at why there is only 1 HW queue for iser.
>
> 2185 int scsi_mq_setup_tags(struct Scsi_Host *shost)
> 2186 {
> ...
> 2199         shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
>
>
> It seems because iser code does not set shost->nr_hw_queues at all.
>
> Why?

The iscsi driver has not yet been converted to scsi_mq and iser as
an iscsi transport still does not use multi-queue.

In iscsi, a hw queue maps to an iscsi session. In order to support
multi-queue we need to have iscsi open multiple sessions and map
a session to a queue.

I had some preliminary works on this (joint with Mike Christie) but I
didn't have time thus far to implement a full conversion to scsi-mq.
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