pagewalk: add walk_page_vma()

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

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3891a368e5e0..a4d24f3c5430 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1201,6 +1201,7 @@ 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 a/mm/pagewalk.c b/mm/pagewalk.c
index d9cc3caae802..4c9a653ba563 100644
--- a/mm/pagewalk.c
+++ b/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);
+}