Re: [PATCH] nvme-fabrics: fix kato initialization

["George, Martin" <Martin.George@netapp.com>]

On Fri, 2021-02-19 at 17:42 +0100, Hannes Reinecke wrote:
> On 2/18/21 11:04 AM, Martin George wrote:
> > Currently kato is initialized to NVME_DEFAULT_KATO for both
> > discovery & i/o controllers. This is a problem specifically
> > for non-persistent discovery controllers since it always ends
> > up with a non-zero kato value. Fix this by initializing kato
> > to zero instead, and ensuring various controllers are assigned
> > appropriate kato values as follows:
> > 
> > non-persistent controllers  - kato set to zero
> > persistent controllers      - kato set to NVMF_DEV_DISC_TMO
> >                                (or any positive int via nvme-cli)
> > i/o controllers             - kato set to NVME_DEFAULT_KATO
> >                                (or any positive int via nvme-cli)
> > 
> > Signed-off-by: Martin George <marting@netapp.com>
> > ---
> >   drivers/nvme/host/fabrics.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/nvme/host/fabrics.c
> > b/drivers/nvme/host/fabrics.c
> > index 5dfd806fc2d2..604ab0e5a2ad 100644
> > --- a/drivers/nvme/host/fabrics.c
> > +++ b/drivers/nvme/host/fabrics.c
> > @@ -630,7 +630,7 @@ static int nvmf_parse_options(struct
> > nvmf_ctrl_options *opts,
> >       opts->queue_size = NVMF_DEF_QUEUE_SIZE;
> >       opts->nr_io_queues = num_online_cpus();
> >       opts->reconnect_delay = NVMF_DEF_RECONNECT_DELAY;
> > -     opts->kato = NVME_DEFAULT_KATO;
> > +     opts->kato = 0;
> >       opts->duplicate_connect = false;
> >       opts->fast_io_fail_tmo = NVMF_DEF_FAIL_FAST_TMO;
> >       opts->hdr_digest = false;
> > @@ -893,6 +893,9 @@ static int nvmf_parse_options(struct
> > nvmf_ctrl_options *opts,
> >               opts->nr_write_queues = 0;
> >               opts->nr_poll_queues = 0;
> >               opts->duplicate_connect = true;
> > +     } else {
> > +             if (!opts->kato)
> > +                     opts->kato = NVME_DEFAULT_KATO;
> >       }
> >       if (ctrl_loss_tmo < 0) {
> >               opts->max_reconnects = -1;
> > 
> Can't you merge this with the previous patch 'ensure zero-kato ..'?
> 

Well, you are right that both the previous patch (i.e. 'ensure zero
kato for non-persistent controllers') & this current patch are jointly
required for assigning proper kato values to the various controllers,
so it would have made sense to merge the two. But the previous one is a
nvme-cli patch, whereas this current one is a kernel patch. That's why
I chose to create separate individual patches itself here.

So I hope this is good enough. If not, please let me know what's the
right way to proceed here.

-Martin
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