thp: share get_huge_page_tail()

BugLink: http://bugs.launchpad.net/bugs/890952

commit b35a35b556f5e6b7993ad0baf20173e75c09ce8c upstream.

This avoids duplicating the function in every arch gup_fast.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 0 insertions, 11 deletions

diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index da33a0281d9..65cb06e2af4 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -48,17 +48,6 @@ static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
         return 1;
 }
 
-static inline void get_huge_page_tail(struct page *page)
-{
-        /*
-         * __split_huge_page_refcount() cannot run
-         * from under us.
-         */
-        VM_BUG_ON(page_mapcount(page) < 0);
-        VM_BUG_ON(atomic_read(&page->_count) != 0);
-        atomic_inc(&page->_mapcount);
-}
-
 static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
                 unsigned long end, int write, struct page **pages, int *nr)
 {