[dm-devel] [PATCH]: create sysfs file, dh_state for SCSI devices even if they are not in the inteernal lists
Chandra Seetharaman
sekharan at us.ibm.com
Mon Aug 3 19:51:39 UTC 2009
Hi Hannes,
Can you comment on this please.
If you are convinced with my justification, please send an ACK.
Thanks & Regards,
chandra
On Mon, 2009-06-29 at 12:30 -0700, Chandra Seetharaman wrote:
> On Mon, 2009-06-29 at 09:40 +0200, Hannes Reinecke wrote:
> > Chandra Seetharaman wrote:
> > > Create the sysfs file, dh_state even if the new SCSI device is not
> > > in the any of the device handler's internal lists.
> > >
> > > Signed-Off-by: Chandra Seetharaman <sekharan at us.ibm.com>
> > > ---
> > > drivers/scsi/device_handler/scsi_dh.c | 11 ++++-------
> > > 1 file changed, 4 insertions(+), 7 deletions(-)
> > >
> > > Index: linux-2.6.31-rc1/drivers/scsi/device_handler/scsi_dh.c
> > > ===================================================================
> > > --- linux-2.6.31-rc1.orig/drivers/scsi/device_handler/scsi_dh.c
> > > +++ linux-2.6.31-rc1/drivers/scsi/device_handler/scsi_dh.c
> > > @@ -304,18 +304,15 @@ static int scsi_dh_notifier(struct notif
> > > sdev = to_scsi_device(dev);
> > >
> > > if (action == BUS_NOTIFY_ADD_DEVICE) {
> > > + err = device_create_file(dev, &scsi_dh_state_attr);
> > > + /* don't care about err */
> > > devinfo = device_handler_match(NULL, sdev);
> > > - if (!devinfo)
> > > - goto out;
> > > -
> > > - err = scsi_dh_handler_attach(sdev, devinfo);
> > > - if (!err)
> > > - err = device_create_file(dev, &scsi_dh_state_attr);
> > > + if (devinfo)
> > > + err = scsi_dh_handler_attach(sdev, devinfo);
> > > } else if (action == BUS_NOTIFY_DEL_DEVICE) {
> > > device_remove_file(dev, &scsi_dh_state_attr);
> > > scsi_dh_handler_detach(sdev, NULL);
> > > }
> > > -out:
> > > return err;
> > > }
> > >
> > >
> > >
> > > --
> > > dm-devel mailing list
> > > dm-devel at redhat.com
> > > https://www.redhat.com/mailman/listinfo/dm-devel
> > NACK.
> >
> > This will create sysfs attributes even if the attach()
> > failed for other reason like a generic error. So we'll end
> > up with device handler attributes and no device handler attached.
>
> we do not have to worry about if attach failed or succeeded. We will
> have "detached" if there is no device handler is attached to a device.
>
> Basically, existence of this file simply means that scsi_dh module is
> active, only the contents of this file will indicate if any device
> handler is attached or not.
>
> We are just creating the file dh_state for each SCSI device that exists
> and that is the only way non-in-built devices can be attached to a
> handler by the end-user.
>
> Do note that we do create this file for all the existing scsi devices
> when the scsi_dh module is inserted (see scsi_dh_init()).
>
> >
> > Not a good idea.
>
> I do not agree, and we do need to have this fix for dh_state file to be
> functionally useful.
>
> >
> > Cheers,
> >
> > Hannes
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