Re: [PATCH/RFC v3] allow userspace to modify scsi command filter on per device basis

[Jens Axboe <jens.axboe@oracle.com>]

On Thu, Jun 26 2008, Adel Gadllah wrote:
> 2008/6/18 Peter Jones <pjones@redhat.com>:
> > Douglas Gilbert wrote:
> >>
> >> Peter Jones wrote:
> >>>
> >>> FUJITA Tomonori wrote:
> >>>
> >>>> Well, this changes sg behaviour since sg's allow_ops filter has a
> >>>> access permission different from blk_verify_command filter's.
> >>>
> >>>  >
> >>>>
> >>>> I guess that the first thing you need to do is that figuring out a
> >>>> proper access permission for each command, which sg maintainer, etc
> >>>> can agree. It's pretty hard and that's the reason why this patch has
> >>>> not been merged for years, I think.
> >>>
> >>> I don't think this logic is sound.
> >>
> >> That depends on your viewpoint.
> >
> > My viewpoint is this:
> >
> > 1) Whether you agree with his reasons or not, Linus made it pretty clear
> > that he's against removing the command filter (see
> > http://marc.info/?l=linux-scsi&m=115419945212450&w=2 )
> > 2) Having different code paths use different filtering code just adds more
> > confusion.
> > 3) If we're going to have filtering, it should be configurable on a
> > per-device basis from userland.
> >
> > Which of these do you disagree with?
> >
> > [...]
> >>
> >> Are per device command filters being proposed?
> >
> > Yes, that's what the patch implements.  And it allows the userland to
> > configure them according to the needs of the hardware.
> 
> Jens can we add merge this for .27 or does anyone still has objections?

Sure, I think it's a good idea. Personally I'd rather get rid of the
filter, but that isn't an option. So the next best thing is to make it
really per-device and exposed and tweakable. Thanks for picking up the
abandoned patch and updating it, I'll add it for 2.6.27.

-- 
Jens Axboe