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

Sagi Grimberg
2018-01-17T09:54:21Z

> Sagi,
>
>> Isn't a bit backwards that each individual driver needs this knob to
>> modify the block layer behavior? I think a better approach would be to
>> get rid of the drivers modparams and simply add a block sysfs knob
>> that would take the knob guard if supported...
>
> Originally the IP checksum thing was an optimization for a single
> device. But others adopted it as well so it grew from being a driver
> tweak to a common feature.
>
> I don't have a problem adding a way to toggle it at the block layer. But
> it would have to be an additional knob.

Personally I think that the clean way to have it is that the driver
exposes capabilities and the core selects the method instead of
having each driver expose what it supports based on the desired method.

But I really don't care that much, if its not something we consider
worth doing then I can easily ack this patch.

> We can't nuke the module parameters without breaking a ton of stuff...

Correct, but we can gradually deprecate them..