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/20221021101141.84170-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
index f3fafb7..37dc020 100644 (file)
--- 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 2ff3a5b..0a5d71a 100644 (file)
--- 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);
 }