On Mon, Nov 18, 2019 at 08:24:04PM +0800, linmiaohe wrote:
>From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
>
>The jump labels try_prev and none are not really needed
>in find_mergeable_anon_vma(), eliminate them to improve
>readability.
>
>Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
>Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
>Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>---
>-v2:
> Fix commit descriptions and further simplify the code
> as suggested by David Hildenbrand and John Hubbard.
>-v3:
> Rewrite patch version info. Don't show this in commit log.
>-v4:
> Get rid of var near completely as well.
>---
> mm/mmap.c | 36 ++++++++++++++++--------------------
> 1 file changed, 16 insertions(+), 20 deletions(-)
>
>diff --git a/mm/mmap.c b/mm/mmap.c
>index 91d5e097a4ed..4d93bda30eac 100644
>--- a/mm/mmap.c
>+++ b/mm/mmap.c
>@@ -1273,26 +1273,22 @@ static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_
> */
> struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
> {
>- struct anon_vma *anon_vma;
>- struct vm_area_struct *near;
>-
>- near = vma->vm_next;
>- if (!near)
>- goto try_prev;
>-
>- anon_vma = reusable_anon_vma(near, vma, near);
>- if (anon_vma)
>- return anon_vma;
>-try_prev:
>- near = vma->vm_prev;
>- if (!near)
>- goto none;
>-
>- anon_vma = reusable_anon_vma(near, near, vma);
>- if (anon_vma)
>- return anon_vma;
>-none:
>+ struct anon_vma *anon_vma = NULL;
>+
>+ /* Try next first. */
>+ if (vma->vm_next) {
>+ anon_vma = reusable_anon_vma(vma->vm_next, vma, vma->vm_next);
>+ if (anon_vma)
>+ return anon_vma;
>+ }
>+
>+ /* Try prev next. */
>+ if (vma->vm_prev)
>+ anon_vma = reusable_anon_vma(vma->vm_prev, vma->vm_prev, vma);
>+
> /*
>+ * We might reach here with anon_vma == NULL if we can't find
>+ * any reusable anon_vma.
> * There's no absolute need to look only at touching neighbours:
> * we could search further afield for "compatible" anon_vmas.
> * But it would probably just be a waste of time searching,
>@@ -1300,7 +1296,7 @@ struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
> * We're trying to allow mprotect remerging later on,
> * not trying to minimize memory used for anon_vmas.
> */
>- return NULL;
>+ return anon_vma;
> }
>
> /*
>--
>2.21.GIT
--
Wei Yang
Help you, Help me
