Re: [PATCH v2 1/7] scsi: libsas: reset the negotiated_linkrate when phy is down

[Jason Yan]

On 2019/1/30 21:08, John Garry wrote:
> On 30/01/2019 08:24, Jason Yan wrote:
> > If the device is unplugged or disconnected, the negotiated_linkrate
> > still can be seen from the userspace by sysfs. This makes people
> > confused and leaks information of the device last used. So let's reset
> > the negotiated_linkrate after the phy is down.
> >
> > Signed-off-by: Jason Yan <yanaijie@xxxxxxxxxx>
> > CC: John Garry <john.garry@xxxxxxxxxx>
> > CC: Johannes Thumshirn <jthumshirn@xxxxxxx>
> > CC: Ewan Milne <emilne@xxxxxxxxxx>
> > CC: Christoph Hellwig <hch@xxxxxx>
> > CC: Tomas Henzl <thenzl@xxxxxxxxxx>
> > CC: Dan Williams <dan.j.williams@xxxxxxxxx>
> > CC: Hannes Reinecke <hare@xxxxxxxx>
> > ---
> >  drivers/scsi/libsas/sas_expander.c | 2 ++
> >  include/scsi/libsas.h              | 3 +++
> >  2 files changed, 5 insertions(+)
> >
> > diff --git a/drivers/scsi/libsas/sas_expander.c
> > b/drivers/scsi/libsas/sas_expander.c
> > index 17eb4185f29d..7b0e6dcef6e6 100644
> > --- a/drivers/scsi/libsas/sas_expander.c
> > +++ b/drivers/scsi/libsas/sas_expander.c
> > @@ -1904,6 +1904,8 @@ static void sas_unregister_devs_sas_addr(struct
> > domain_device *parent,
> >                  &parent->port->sas_port_del_list);
> >          phy->port = NULL;
> >      }
> > +    if (phy->phy)
> > +        phy->phy->negotiated_linkrate = SAS_LINK_RATE_UNKNOWN;
>
> Does this work for both PHYs which were either directly attached or just
> forming part of a wideport?
>
> Please also note that the expander PHY which was previously attached may
> also show the incorrect value.

Good catch, all PHYs need to do this, not only the last PHY of the wideport.

> >  }
> >
> >  static int sas_discover_bfs_by_root_level(struct domain_device *root,
> > diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
> > index 3de3b10da19a..420156cea3ee 100644
> > --- a/include/scsi/libsas.h
> > +++ b/include/scsi/libsas.h
> > @@ -448,6 +448,9 @@ static inline void sas_phy_disconnected(struct
> > asd_sas_phy *phy)
> >  {
> >      phy->oob_mode = OOB_NOT_CONNECTED;
> >      phy->linkrate = SAS_LINK_RATE_UNKNOWN;
> > +
>
> Then idea behind sas_phy_disconnected() was to set root PHY values only:
>
> /* Before calling a notify event, LLDD should use this function
>   * when the link is severed (possibly from its tasklet).
>   * The idea is that the Class only reads those, while the LLDD,
>   * can R/W these (thus avoiding a race)
>
> libsas does set sas_phy negotiated_linkrate (but only for expander
> PHYs), so not the perfect place to set this. I'm nitpicking a bit here.

I don't want to put it here. I asked chenxiang to fix this in LLDD, but 
he insist libsas to do this. Would you please discuss with chenxiang and 
come to an agreement?

> > +    if (phy->phy)
> > +        phy->phy->negotiated_linkrate = SAS_LINK_RATE_UNKNOWN;
> >  }
> >
> >  static inline unsigned int to_sas_gpio_od(int device, int bit)
>
> Thanks,
>
> >
>
>
>
>
>
> .