[RESEND PATCH] nvme: explicitly use normal NVMe error handling when appropriate

[Mike Snitzer]

On Thu, Aug 13 2020 at  2:43pm -0400,
Christoph Hellwig <hch at infradead.org> wrote:

> On Thu, Aug 13, 2020 at 01:47:04PM -0400, Mike Snitzer wrote:
> > This is just a tweak to improve the high-level fault tree of core NVMe
> > error handling.  No functional change, but for such basic errors,
> > avoiding entering nvme_failover_req is meaningful on a code flow level.
> > Makes code to handle errors that need local retry clearer by being more
> > structured, less circuitous.
> > 
> > Allows NVMe core's handling of such errors to be more explicit and live
> > in core.c rather than multipath.c -- so things like ACRE handling can be
> > made explicitly part of core and not nested under nvme_failover_req's
> > relatively obscure failsafe that returns false for anything it doesn't
> > care about.
> 
> If we're going that way I'd rather do something like the (untested)
> patch below that adds a dispostion function with a function that
> decides it and then just switches on it:

YES!  That is such a huge improvement (certainly on a code clarity
level).  I haven't reviewed or tested the relative performance or
function of before vs after (will do) but I really like this approach.

Thanks,
Mike