thp: split_huge_page_mm/vma

split_huge_page_pmd compat code.  Each one of those would need to be
expanded to hundred of lines of complex code without a fully reliable
split_huge_page_pmd design.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 61fb985..863f875 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -179,6 +179,7 @@
 	if (pud_none_or_clear_bad(pud))
 		goto out;
 	pmd = pmd_offset(pud, 0xA0000);
+	split_huge_page_pmd(mm, pmd);
 	if (pmd_none_or_clear_bad(pmd))
 		goto out;
 	pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index e6d3512..83b7df3 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -514,6 +514,7 @@
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
+		split_huge_page_pmd(vma->vm_mm, pmd);
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
 		if (check_pte_range(vma, pmd, addr, next, nodes,
diff --git a/mm/mincore.c b/mm/mincore.c
index 9ac42dc..9959bb4 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -154,6 +154,7 @@
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
+		split_huge_page_pmd(vma->vm_mm, pmd);
 		if (pmd_none_or_clear_bad(pmd))
 			mincore_unmapped_range(vma, addr, next, vec);
 		else
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 4c51338..bd27db6 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -88,6 +88,7 @@
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
+		split_huge_page_pmd(mm, pmd);
 		if (pmd_none_or_clear_bad(pmd))
 			continue;
 		change_pte_range(mm, pmd, addr, next, newprot, dirty_accountable);
diff --git a/mm/mremap.c b/mm/mremap.c
index b09eefa..9925b63 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -41,6 +41,7 @@
 		return NULL;
 
 	pmd = pmd_offset(pud, addr);
+	split_huge_page_pmd(mm, pmd);
 	if (pmd_none_or_clear_bad(pmd))
 		return NULL;
 
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 38cc58b..7cfa6ae 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -34,6 +34,7 @@
 	pmd = pmd_offset(pud, addr);
 	do {
 		next = pmd_addr_end(addr, end);
+		split_huge_page_pmd(walk->mm, pmd);
 		if (pmd_none_or_clear_bad(pmd)) {
 			if (walk->pte_hole)
 				err = walk->pte_hole(addr, next, walk);