On Tue 24-03-15 11:30:35, Jason Low wrote:

On Tue, 2015-03-24 at 11:30 +0100, Michal Hocko wrote:

quoted

On Mon 23-03-15 15:44:40, Jason Low wrote:

quoted

Commit 38c5ce936a08 converted ACCESS_ONCE usage in gup_pmd_range() to
READ_ONCE, since ACCESS_ONCE doesn't work reliably on non-scalar types.

This patch removes the rest of the usages of ACCESS_ONCE, and use
READ_ONCE for the read accesses. This also makes things cleaner,
instead of using separate/multiple sets of APIs.

Signed-off-by: Jason Low <redacted>

Makes sense to me. I would prefer a patch split into two parts. One which
changes potentially dangerous usage of ACCESS_ONCE and the cleanup. This
will make the life of those who backport patches into older kernels
easier a bit.

Okay, so have a patch 1 which fixes the following:

    pte_t pte = ACCESS_ONCE(*ptep);
    pgd_t pgd = ACCESS_ONCE(*pgdp);

and the rest of the changes in the cleanup patch 2?

Thanks!

quoted

I won't insist though.

Acked-by: Michal Hocko <redacted>

Thanks,
Jason

-- 
Michal Hocko
SUSE Labs