Re: [PATCH 2/3] nvme: Retrieve the required IO queue entry size from the controller

From: Christoph Hellwig
Date: Tue Jul 16 2019 - 08:05:51 EST


On Tue, Jul 16, 2019 at 08:58:28PM +1000, Benjamin Herrenschmidt wrote:
> The main risk is if existing controllers return crap in SQES and we try
> to then use that crap. The rest should essentially be NOPs.
>
> Maybe I should add some kind of printk to warn in case we use/detect a
> non-standard size. That would help diagnosing issues.

Given that the spec currently requires bits 0 to 3 of SQES to be 6
we might as well not check SQES and just hardcode it to 6 or 7 depending
on the quirk. That actually was my initial idea, I just suggested using
the SQES naming and indexing.