rmap: fix walk during fork
rmap: fix walk during fork

The below bug in fork led to the rmap walk finding the parent huge-pmd
twice instead of just once, because the anon_vma_chain objects of the
child vma still point to the vma->vm_mm of the parent.

The patch fixes it by making the rmap walk accurate during fork.  It's not
a big deal normally but it worth being accurate considering the cost is
the same.

Signed-off-by: Andrea Arcangeli <6cb163d975a8c4c46420677e0054b55c39bdb339@redhat.com>
Acked-by: Johannes Weiner <5332d5d6802f0c4180a1f65eb38cf05f0ccdfd97@redhat.com>
Acked-by: Rik van Riel <a21938f5d463ddf41aa718934c205ca2cce8ebbc@redhat.com>
Acked-by: Hugh Dickins <d3abdf3e2800e6cb849f11b81e6eb50b34d96431@google.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas