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SubjectRe: [PATCH v3] qla2xxx: Return EBUSY on fcport deletion

On Tue, 13 Oct 2020, Daniel Wagner wrote:

> On Tue, Oct 13, 2020 at 10:59:18AM +1100, Finn Thain wrote:
> >
> > On Mon, 12 Oct 2020, Daniel Wagner wrote:
> >
> > > When the fcport is about to be deleted we should return EBUSY
> > > instead of ENODEV. Only for EBUSY the request will be requeued in a
> > > multipath setup.
> > >
> > > Also in case we have a valid qpair but the firmware has not yet
> > > started return EBUSY to avoid dropping the request.
> > >
> > > Signed-off-by: Daniel Wagner <dwagner@suse.de>
> > > ---
> > >
> > > v3: simplify test logic as suggested by Arun.
> >
> > Not exactly a "simplification": there was a change of behaviour
> > between v2 and v3. It seems the commit log no longer reflects the
> > code.
>
> How so? I am struggling to see how it could be a change in behavior. But
> then I sometimes fail at simple logic ;)
>

Me too, so I confirmed the result by executing the code snippets.

> v2 and v3 will return ENODEV if qpair or fcport are invalid and for
> EBUSY one of the other condition needs be true. The difference between
> v2 and v3 should only be the order how tests are executed. The outcome
> should be the same.
>

Here's a truth table for v2:

qpair fw_started fcport deleted result
---------------------------------------
F X F X -ENODEV
F F T F -ENODEV
F F T T -EBUSY *
F T T F -ENODEV
F T T T -EBUSY *
T F F X -EBUSY *
T F T X -EBUSY
T T F X -ENODEV
T T T F neither
T T T T -EBUSY

Here's a truth table for v3:

qpair fw_started fcport deleted result
---------------------------------------
F X F X -ENODEV
F F T F -ENODEV
F F T T -ENODEV *
F T T F -ENODEV
F T T T -ENODEV *
T F F X -ENODEV *
T F T X -EBUSY
T T F X -ENODEV
T T T F neither
T T T T -EBUSY

The asterisks mark the changed rows.

I don't know whether the changes in v3 are desirable or not, I was just
pointing out that the commit log ("valid qpair but the firmware has not
yet started return EBUSY") now seems to disagree with the code.

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