| Message ID | 20180529022309.21071-4-yanaijie@huawei.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
Looks good,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
On 29/05/2018 03:23, Jason Yan wrote: > If we went into sas_rediscover_dev() the attached_sas_addr was already > insured not to be zero. So it's unnecessary to check if the > attached_sas_addr is zero. > > And although if the sas address is not changed, we always have to > unregister the old device when we are going to register a new one. We > cannot just leave the device there and bring up the new. > > Signed-off-by: Jason Yan <yanaijie@huawei.com> > CC: chenxiang <chenxiang66@hisilicon.com> > CC: John Garry <john.garry@huawei.com> > CC: Johannes Thumshirn <jthumshirn@suse.de> > CC: Ewan Milne <emilne@redhat.com> > CC: Christoph Hellwig <hch@lst.de> > CC: Tomas Henzl <thenzl@redhat.com> > CC: Dan Williams <dan.j.williams@intel.com> > CC: Hannes Reinecke <hare@suse.com> > --- > drivers/scsi/libsas/sas_expander.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index 8b7114348def..629c580d906b 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -2054,14 +2054,11 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id, bool last) > return res; > } > > - /* delete the old link */ > - if (SAS_ADDR(phy->attached_sas_addr) && > - SAS_ADDR(sas_addr) != SAS_ADDR(phy->attached_sas_addr)) { > - SAS_DPRINTK("ex %016llx phy 0x%x replace %016llx\n", > - SAS_ADDR(dev->sas_addr), phy_id, > - SAS_ADDR(phy->attached_sas_addr)); > - sas_unregister_devs_sas_addr(dev, phy_id, last); > - } The preceeding checks in code check for no device/comm fail or SATA flutter. If we're rediscovering the device and the SAS address has not changed, then why previously still try to discover a new device? I'm guessing sas_discover_new() had no affect in this case, since maybe since the PHY was already discovered. But that would not make sense since you say "we are going to register a new one". Or, if we are always going to register a new one, how did we ensure we always unregistered the old device previously (when SAS address did not change)? > + /* we always have to delete the old device when we went here */ > + SAS_DPRINTK("ex %016llx phy 0x%x replace %016llx\n", > + SAS_ADDR(dev->sas_addr), phy_id, > + SAS_ADDR(phy->attached_sas_addr)); > + sas_unregister_devs_sas_addr(dev, phy_id, last); > > return sas_discover_new(dev, phy_id); > } >
On 2018/5/31 23:09, John Garry wrote: > On 29/05/2018 03:23, Jason Yan wrote: >> If we went into sas_rediscover_dev() the attached_sas_addr was already >> insured not to be zero. So it's unnecessary to check if the >> attached_sas_addr is zero. >> >> And although if the sas address is not changed, we always have to >> unregister the old device when we are going to register a new one. We >> cannot just leave the device there and bring up the new. >> >> Signed-off-by: Jason Yan <yanaijie@huawei.com> >> CC: chenxiang <chenxiang66@hisilicon.com> >> CC: John Garry <john.garry@huawei.com> >> CC: Johannes Thumshirn <jthumshirn@suse.de> >> CC: Ewan Milne <emilne@redhat.com> >> CC: Christoph Hellwig <hch@lst.de> >> CC: Tomas Henzl <thenzl@redhat.com> >> CC: Dan Williams <dan.j.williams@intel.com> >> CC: Hannes Reinecke <hare@suse.com> >> --- >> drivers/scsi/libsas/sas_expander.c | 13 +++++-------- >> 1 file changed, 5 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/scsi/libsas/sas_expander.c >> b/drivers/scsi/libsas/sas_expander.c >> index 8b7114348def..629c580d906b 100644 >> --- a/drivers/scsi/libsas/sas_expander.c >> +++ b/drivers/scsi/libsas/sas_expander.c >> @@ -2054,14 +2054,11 @@ static int sas_rediscover_dev(struct >> domain_device *dev, int phy_id, bool last) >> return res; >> } >> >> - /* delete the old link */ >> - if (SAS_ADDR(phy->attached_sas_addr) && >> - SAS_ADDR(sas_addr) != SAS_ADDR(phy->attached_sas_addr)) { >> - SAS_DPRINTK("ex %016llx phy 0x%x replace %016llx\n", >> - SAS_ADDR(dev->sas_addr), phy_id, >> - SAS_ADDR(phy->attached_sas_addr)); >> - sas_unregister_devs_sas_addr(dev, phy_id, last); >> - } > > The preceeding checks in code check for no device/comm fail or SATA > flutter. > > If we're rediscovering the device and the SAS address has not changed, > then why previously still try to discover a new device? I'm guessing > sas_discover_new() had no affect in this case, since maybe since the PHY > was already discovered. When we went here, means it is not flutter, something must change, either the device type or the phy address. Then we call sas_discover_new(). And sas_discover_new() sure *have* effect in this case. Please check sas_discover_new() carefully. But that would not make sense since you say "we > are going to register a new one". Or, if we are always going to register > a new one, how did we ensure we always unregistered the old device > previously (when SAS address did not change)? > If SAS address did not change, the device type must changed, otherwise it will be a "flutter" and won't get here. So if the device type changed, do we have a reason to keep the device? I don't think so. >> + /* we always have to delete the old device when we went here */ >> + SAS_DPRINTK("ex %016llx phy 0x%x replace %016llx\n", >> + SAS_ADDR(dev->sas_addr), phy_id, >> + SAS_ADDR(phy->attached_sas_addr)); >> + sas_unregister_devs_sas_addr(dev, phy_id, last); >> >> return sas_discover_new(dev, phy_id); >> } >> > > > > . >
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index 8b7114348def..629c580d906b 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -2054,14 +2054,11 @@ static int sas_rediscover_dev(struct domain_device *dev, int phy_id, bool last) return res; } - /* delete the old link */ - if (SAS_ADDR(phy->attached_sas_addr) && - SAS_ADDR(sas_addr) != SAS_ADDR(phy->attached_sas_addr)) { - SAS_DPRINTK("ex %016llx phy 0x%x replace %016llx\n", - SAS_ADDR(dev->sas_addr), phy_id, - SAS_ADDR(phy->attached_sas_addr)); - sas_unregister_devs_sas_addr(dev, phy_id, last); - } + /* we always have to delete the old device when we went here */ + SAS_DPRINTK("ex %016llx phy 0x%x replace %016llx\n", + SAS_ADDR(dev->sas_addr), phy_id, + SAS_ADDR(phy->attached_sas_addr)); + sas_unregister_devs_sas_addr(dev, phy_id, last); return sas_discover_new(dev, phy_id); }
If we went into sas_rediscover_dev() the attached_sas_addr was already insured not to be zero. So it's unnecessary to check if the attached_sas_addr is zero. And although if the sas address is not changed, we always have to unregister the old device when we are going to register a new one. We cannot just leave the device there and bring up the new. Signed-off-by: Jason Yan <yanaijie@huawei.com> CC: chenxiang <chenxiang66@hisilicon.com> CC: John Garry <john.garry@huawei.com> CC: Johannes Thumshirn <jthumshirn@suse.de> CC: Ewan Milne <emilne@redhat.com> CC: Christoph Hellwig <hch@lst.de> CC: Tomas Henzl <thenzl@redhat.com> CC: Dan Williams <dan.j.williams@intel.com> CC: Hannes Reinecke <hare@suse.com> --- drivers/scsi/libsas/sas_expander.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)