---
 mm/nommu.c |  6 ++++--
 mm/vma.c   |  6 +++---
 mm/vma.h   | 12 ++++++++++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index c0a0869cd0d6..2a0136f6081d 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c

@@ -41,6 +41,7 @@
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include "internal.h"
+#include "vma.h"
 
 unsigned long highest_memmap_pfn;
 int heap_stack_gap = 0;

@@ -1361,7 +1362,8 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		region->vm_top = region->vm_end = new->vm_end = addr;
 	} else {
 		region->vm_start = new->vm_start = addr;
-		region->vm_pgoff = new->vm_pgoff += npages;

+		vma_add_pgoff(new, npages);
+		region->vm_pgoff = vma_start_pgoff(new);
 	}
 
 	vma_iter_config(vmi, new->vm_start, new->vm_end);

@@ -1378,7 +1380,7 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	delete_nommu_region(vma->vm_region);
 	if (new_below) {
 		vma->vm_region->vm_start = vma->vm_start = addr;
-		vma->vm_pgoff += npages;
+		vma_add_pgoff(vma, npages);
 		vma->vm_region->vm_pgoff = vma_start_pgoff(vma);
 	} else {
 		vma->vm_region->vm_end = vma->vm_end = addr;

diff --git a/mm/vma.c b/mm/vma.c
index 7aa0149f076c..bdd99ba56b4d 100644
--- a/mm/vma.c
+++ b/mm/vma.c

@@ -517,7 +517,7 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		new->vm_end = addr;
 	} else {
 		new->vm_start = addr;
-		new->vm_pgoff += linear_page_delta(vma, addr);
+		vma_add_pgoff(new, linear_page_delta(vma, addr));
 	}
 
 	err = -ENOMEM;

@@ -556,7 +556,7 @@ __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
 
 	if (new_below) {
 		vma->vm_start = addr;
-		vma->vm_pgoff += (addr - new->vm_start) >> PAGE_SHIFT;
+		vma_add_pgoff(vma, (addr - new->vm_start) >> PAGE_SHIFT);

 	} else {
 		vma->vm_end = addr;
 	}

@@ -3305,7 +3305,7 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address)
 				vm_stat_account(mm, vma->vm_flags, grow);
 				anon_rmap_tree_pre_update_vma(vma);
 				vma->vm_start = address;
-				vma->vm_pgoff -= grow;
+				vma_sub_pgoff(vma, grow);
 				/* Overwrite old entry in mtree. */
 				vma_iter_store_overwrite(&vmi, vma);
 				anon_rmap_tree_post_update_vma(vma);

diff --git a/mm/vma.h b/mm/vma.h
index 2342516ce00e..47fe35e5307e 100644
--- a/mm/vma.h
+++ b/mm/vma.h

@@ -247,6 +247,18 @@ static inline pgoff_t vmg_end_pgoff(const struct vma_merge_struct *vmg)
 	return vmg_start_pgoff(vmg) + vmg_pages(vmg);
 }
 
+static inline void vma_add_pgoff(struct vm_area_struct *vma, pgoff_t delta)
+{
+	vma_assert_can_modify(vma);
+	vma->vm_pgoff += delta;
+}
+
+static inline void vma_sub_pgoff(struct vm_area_struct *vma, pgoff_t delta)
+{
+	vma_assert_can_modify(vma);
+	vma->vm_pgoff -= delta;
+}
+
 #define VMG_STATE(name, mm_, vmi_, start_, end_, vma_flags_, pgoff_)	\
 	struct vma_merge_struct name = {				\
 		.mm = mm_,						\