thp: mprotect: transparent huge page support

Natively handle huge pmds when changing page tables on behalf of
mprotect().

I left out update_mmu_cache() because we do not need it on x86 anyway but
more importantly the interface works on ptes, not pmds.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 25125fb6acf7..c590b08c6fa6 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -22,6 +22,8 @@ extern int zap_huge_pmd(struct mmu_gather *tlb,
 extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
                         unsigned long addr, unsigned long end,
                         unsigned char *vec);
+extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
+                        unsigned long addr, pgprot_t newprot);
 
 enum transparent_hugepage_flag {
         TRANSPARENT_HUGEPAGE_FLAG,