[PATCH v2 6/9] mm/pagewalk: don't trigger test_walk() in walk_page_vma()

From: David Hildenbrand
Date: Fri Oct 21 2022 - 06:12:56 EST


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.

Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
include/linux/pagewalk.h | 2 ++
mm/pagewalk.c | 7 -------
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);
}

--
2.37.3