mm/pagewalk: don't trigger test_walk() in walk_page_vma()

As Peter points out, the caller passes a single VMA and can just do that
check itself.

And in fact, no existing users rely on test_walk() getting called.  So
let's just remove it and make the implementation slightly more efficient.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

2 files changed, 2 insertions, 7 deletions

diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
index f3fafb731ffd..37dc0208862d 100644
--- a/include/linux/pagewalk.h
+++ b/include/linux/pagewalk.h
@@ -27,6 +27,8 @@ struct mm_walk;
  *			"do page table walk over the current vma", returning
  *			a negative value means "abort current page table walk
  *			right now" and returning 1 means "skip the current vma"
+ *			Note that this callback is not called when the caller
+ *			passes in a single VMA as for walk_page_vma().
  * @pre_vma:            if set, called before starting walk on a non-null vma.
  * @post_vma:           if set, called after a walk on a non-null vma, provided
  *                      that @pre_vma and the vma walk succeeded.
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 2ff3a5bebceb..0a5d71aaf9c7 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -526,18 +526,11 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
 		.vma		= vma,
 		.private	= private,
 	};
-	int err;
 
 	if (!walk.mm)
 		return -EINVAL;
 
 	mmap_assert_locked(walk.mm);
-
-	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);
 }