On Thu, Sep 29, 2011 at 03:45:05PM -0700, Simon Kirby wrote:

Tested against on 2.6.39 with and without this patch, and it
definitely leaks without it and does not leak with it. 3.0 and 3.1-rc8
also seems good with the patch.

Good job, thanks!

I tested on another IDE box (with an old Quantum Fireball 6.4GB!) and

:-)

even with software RAID, I could not see the leak, so I had to use the
original box, of course. The only difference I could see is the test
box has piix and the production box has via82cxxx, but anyway...

It might be because the production box drive is reporting of being
capable of doing write cache flushes, i.e. it should say something like

ideXX: cache flushes supported

in dmesg. idedisk_prep_fn() is contingent on that and is used only then
AFAICT.

Thanks again for testing.

-- 
Regards/Gruss,
    Boris.