Re: [PATCH 0/5] scsi: fnic: use blk_mq_tagset_busy_iter() to walk scsi commands

[Martin Wilck <mwilck@suse.com>]

On Wed, 2021-04-21 at 18:40 +0800, Ming Lei wrote:
> On Wed, Apr 21, 2021 at 12:19:00PM +0200, Martin Wilck wrote:
> > On Wed, 2021-04-21 at 15:55 +0800, Ming Lei wrote:
> > > Hello Guys,
> > > 
> > > fnic uses the following way to walk scsi commands in failure
> > > handling,
> > > which is obvious wrong, because caller of scsi_host_find_tag has
> > > to
> > > guarantee that the tag is active.
> > > 
> > >         for (tag = 0; tag < fnic->fnic_max_tag_id; tag++) {
> > >                                 ...
> > >                 sc = scsi_host_find_tag(fnic->lport->host, tag);
> > >                                 ...
> > >                 }
> > > 
> > > Fix the issue by using blk_mq_tagset_busy_iter() to walk
> > > request/scsi_command.
> > 
> > How does this relate to Hannes' previous patch?
> > https://marc.info/?l=linux-scsi&m=161400059528859&w=2
> 
> oops, this patch is actually same or similar with Hannes's.
> 
> Given these patches are bug fix, can we cherry-pick them for 5.13?

No objections in principle, but the differences between your patch and
Hannes' are pretty large. I couldn't tell which one is more
appropriate.

Question: Both your patch set and Hannes' patch replace a couple of
scsi_host_find_tag() calls in the fnic driver, while leaving some
others in place. It's not clear to me why we can be sure that no
corruption occurs in any of the latter. Could you explain?

Regards,
Martin