[PATCH] Revert "mm: rename _count, field of the struct page, to _refcount"

[Christoph Hellwig]

On Thu, Jun 16, 2016 at 11:22:46AM +0200, Vitaly Kuznetsov wrote:
> _count -> _refcount rename in commit 0139aa7b7fa12 ("mm: rename _count,
> field of the struct page, to _refcount") broke kdump. makedumpfile(8) does
> stuff like READ_MEMBER_OFFSET("page._count", page._count) and fails. While
> it is definitely possible to fix this particular tool I'm not sure about
> other tools which might be doing the same.
> 
> I suggest we remember the "we don't break userspace" rule and revert for
> 4.7 while it's not too late.

Err, sorry - this is not "userspace".  It's crazy crap digging into
kernel internal structure.

The rename was absolutely useful, so fix up your stinking pike in kdump.