Re: [PATCH] Revert "virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon disk hotplug events"

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Aug 03, 2023 at 03:36:44PM -0400, Michael S. Tsirkin wrote:
> On Wed, Jul 05, 2023 at 09:15:23AM +0200, Stefano Garzarella wrote:
> > This reverts commit 8cc5583abe6419e7faaebc9fbd109f34f4c850f2.
> > 
> > That commit causes several problems in Linux as described in the BZ.
> > In particular, after a while, other devices on the bus are no longer
> > usable even if those devices are not affected by the hotunplug.
> > This may be a problem in Linux, but we have not been able to identify
> > it so far. So better to revert this patch until we find a solution.
> > 
> > Also, Oracle, which initially proposed this patch for a problem with
> > Solaris, seems to have already reversed it downstream:
> >     https://linux.oracle.com/errata/ELSA-2023-12065.html
> > 
> > Suggested-by: Thomas Huth <thuth@redhat.com>
> > Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2176702
> > Cc: qemu-stable@nongnu.org
> > Cc: Mark Kanda <mark.kanda@oracle.com>
> > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> 
> OK guys we are reverting this?


ignore me pls, replied to a wrong patch.

> > ---
> >  include/hw/scsi/scsi.h |  1 -
> >  hw/scsi/scsi-bus.c     | 18 ------------------
> >  hw/scsi/virtio-scsi.c  |  2 --
> >  3 files changed, 21 deletions(-)
> > 
> > diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
> > index e2bb1a2fbf..7c8adf10b1 100644
> > --- a/include/hw/scsi/scsi.h
> > +++ b/include/hw/scsi/scsi.h
> > @@ -198,7 +198,6 @@ SCSIDevice *scsi_bus_legacy_add_drive(SCSIBus *bus, BlockBackend *blk,
> >                                        BlockdevOnError rerror,
> >                                        BlockdevOnError werror,
> >                                        const char *serial, Error **errp);
> > -void scsi_bus_set_ua(SCSIBus *bus, SCSISense sense);
> >  void scsi_bus_legacy_handle_cmdline(SCSIBus *bus);
> >  
> >  SCSIRequest *scsi_req_alloc(const SCSIReqOps *reqops, SCSIDevice *d,
> > diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
> > index f80f4cb4fc..42a915f8b7 100644
> > --- a/hw/scsi/scsi-bus.c
> > +++ b/hw/scsi/scsi-bus.c
> > @@ -1617,24 +1617,6 @@ static int scsi_ua_precedence(SCSISense sense)
> >      return (sense.asc << 8) | sense.ascq;
> >  }
> >  
> > -void scsi_bus_set_ua(SCSIBus *bus, SCSISense sense)
> > -{
> > -    int prec1, prec2;
> > -    if (sense.key != UNIT_ATTENTION) {
> > -        return;
> > -    }
> > -
> > -    /*
> > -     * Override a pre-existing unit attention condition, except for a more
> > -     * important reset condition.
> > -     */
> > -    prec1 = scsi_ua_precedence(bus->unit_attention);
> > -    prec2 = scsi_ua_precedence(sense);
> > -    if (prec2 < prec1) {
> > -        bus->unit_attention = sense;
> > -    }
> > -}
> > -
> >  void scsi_device_set_ua(SCSIDevice *sdev, SCSISense sense)
> >  {
> >      int prec1, prec2;
> > diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> > index 45b95ea070..1f56607100 100644
> > --- a/hw/scsi/virtio-scsi.c
> > +++ b/hw/scsi/virtio-scsi.c
> > @@ -1080,7 +1080,6 @@ static void virtio_scsi_hotplug(HotplugHandler *hotplug_dev, DeviceState *dev,
> >  
> >          virtio_scsi_acquire(s);
> >          virtio_scsi_push_event(s, &info);
> > -        scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
> >          virtio_scsi_release(s);
> >      }
> >  }
> > @@ -1112,7 +1111,6 @@ static void virtio_scsi_hotunplug(HotplugHandler *hotplug_dev, DeviceState *dev,
> >      if (virtio_vdev_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG)) {
> >          virtio_scsi_acquire(s);
> >          virtio_scsi_push_event(s, &info);
> > -        scsi_bus_set_ua(&s->bus, SENSE_CODE(REPORTED_LUNS_CHANGED));
> >          virtio_scsi_release(s);
> >      }
> >  }
> > -- 
> > 2.41.0