Re: [PATCH] iscsi_iser: Re-enable 'iser_pi_guard' module parameter

Sagi Grimberg
2018-01-17T09:59:06Z

> Hannes,
>
>> Do we need to keep the parameter?
>> If so we really should be re-enable it; ATM it's just a no-op leading
>> the user to believe something has actually happened.
>
> The driver module parameters existed mainly for the purpose of hw
> testing. One could disable IP checksum and revert to CRC to ensure both
> code paths were working properly. But it wasn't really meant to be
> something ordinary users would ever muck with. Why would anybody use the
> much slower CRC when IP checksum was supported by the hardware? (*)

Agree, but I definitely might not see the full picture here.

> Anyway. I think Sagi's iser_pi_guard patch was a result of that
> transition from driver global checksum setting to per-I/O ditto.

Correct, and due to your comment above.

> I don't have a problem with having a block-level preference knob
> (slightly convoluted to implement since they are different integrity
> profiles). But I do question whether it is worth the hassle. What
> exactly is your use case that requires twiddling this?

I'm not sure its worth it either, I can easily ack this one if that's
the case.