[PATCH v4 03/13] pagewalk: add walk_page_vma()

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

Introduces walk_page_vma(), which is useful for the callers which want to
walk over a given vma.  It's used by later patches.

ChangeLog v3:
- check walk_page_test's return value instead of walk->skip

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h |  1 +
 mm/pagewalk.c      | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git v3.16-rc3.orig/include/linux/mm.h v3.16-rc3/include/linux/mm.h
index 489a63a06a4a..7e9287750866 100644
--- v3.16-rc3.orig/include/linux/mm.h
+++ v3.16-rc3/include/linux/mm.h
@@ -1137,6 +1137,7 @@ struct mm_walk {
 
 int walk_page_range(unsigned long addr, unsigned long end,
 		struct mm_walk *walk);
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 		unsigned long end, unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
diff --git v3.16-rc3.orig/mm/pagewalk.c v3.16-rc3/mm/pagewalk.c
index 91810ba875ea..65fb68df3aa2 100644
--- v3.16-rc3.orig/mm/pagewalk.c
+++ v3.16-rc3/mm/pagewalk.c
@@ -272,3 +272,21 @@ int walk_page_range(unsigned long start, unsigned long end,
 	} while (start = next, start < end);
 	return err;
 }
+
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk)
+{
+	int err;
+
+	if (!walk->mm)
+		return -EINVAL;
+
+	VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem));
+	VM_BUG_ON(!vma);
+	walk->vma = vma;
+	err = walk_page_test(vma->vm_start, vma->vm_end, walk);
+	if (err > 0)
+		return 0;
+	if (err < 0)
+		return err;
+	return __walk_page_range(vma->vm_start, vma->vm_end, walk);
+}
-- 
1.9.3

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