Re: [dm-devel] [PATCH 1/2] block: fix leaks associated with discard request payload

[Mike Snitzer <snitzer redhat com>]

On Thu, Jul 01 2010 at  8:28am -0400,
Mikulas Patocka <mpatocka redhat com> wrote:

> > > It is either/or choice. If the interface isn't fixed NOW, the existing 
> > > flawed zeroed-page-allocation interface gets into RHEL
> > 
> > That's a false dichotomy.  You might see an either apply this hack now
> > or support the interface choice with RHEL, but upstream has the option
> > to fix stuff correctly.  RHEL has never needed my blessing to apply
> > random crap to their kernel before ... why is this patch any different?
> 
> We can't apply non-upstream patches (except few exceptions such as 
> dm-raid45). It makes sense, non-upstream patches have smaller test 
> coverage.
> 
> > And the rest of this rubbish is based on that false premise.  It might
> > help you to take off your SCSI antipathy and see this as a system
> > problem: it actually originates in block and spills out from there.
> > Thus it requires a system solution.
> > 
> > James
> 
> Imagine this: I take a FPGA PCI board, I design a storage controller on it 
> and this controller will need 3 pages to process a discard request. Now I 
> say: I refuse to allocate these 3 pages in the driver because the driver 
> would look ugly --- instead, I demand that everyone in the Linux kernel 
> who creates a discard request must attach 3 pages to the request for my 
> driver.
> 
> Do you think it is correct behavior? Would you accept such a driver? I 
> guess you wouldn't! But this is the same thing that you are doing with 
> SCSI.
> 
> Now lets take it a bit further and I say "I may clean up the driver for my 
> controller one day, when I do it, I remove that 3-page requirement --- and 
> then, everyone who allocated those pages will have to change his code and 
> remove the allocations".
> 
> And this is what you are intending to do with SCSI.

Mikulas,

Jens has already queued up a comprehensive fix (3 patches) that James
and Tomo developed.  Please stop the hostility.. it has no place.

Others,
I'd encourage you to not respond to this thread further ;)

Regards,
Mike