Re: [PATCH] scsi: libsas: Directly kick-off EH when ATA device fell off

[yangxingui]

On 2022/12/16 11:53, Jason Yan wrote:
> Hi Xingui,
>
> On 2022/12/16 11:29, Xingui Yang wrote:
> > If the ATA device fell off, call sas_ata_device_link_abort() directly and
> > mark all outstanding QCs as failed and kick-off EH Immediately. This 
> > avoids
> > having to wait for block layer timeouts.
>
> Why does ATA device need this special operation? SAS device does not 
> have to wait for block layer timeouts?
Hi Jason,
Applications that depend on I/O return may be blocked for 30 seconds, 
and this can be optimized for SATA disks.

Different from SATA disks, I/Os on SAS disks can still be returned if 
they are quickly plugged in after the SAS disks fall off. So I'm not 
sure if this is appropriate for a sas disk.
BTW, I wish the sas disk did the same.

Thanks,
Xingui
> Thanks,
> Jason
>
> > Signed-off-by: Xingui Yang <yangxingui@xxxxxxxxxx>
> > ---
> >   drivers/scsi/libsas/sas_discover.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/scsi/libsas/sas_discover.c 
> > b/drivers/scsi/libsas/sas_discover.c
> > index d5bc1314c341..bd22741daa99 100644
> > --- a/drivers/scsi/libsas/sas_discover.c
> > +++ b/drivers/scsi/libsas/sas_discover.c
> > @@ -362,6 +362,11 @@ static void sas_destruct_ports(struct 
> > asd_sas_port *port)
> >   void sas_unregister_dev(struct asd_sas_port *port, struct 
> > domain_device *dev)
> >   {
> > +    if (test_bit(SAS_DEV_GONE, &dev->state) &&
> > +        (dev->dev_type == SAS_SATA_DEV ||
> > +        (dev->tproto & SAS_PROTOCOL_STP)))
> > +        sas_ata_device_link_abort(dev, false);
> > +
> >       if (!test_bit(SAS_DEV_DESTROY, &dev->state) &&
> >           !list_empty(&dev->disco_list_node)) {
> >           /* this rphy never saw sas_rphy_add */
> .