On 11/17/19 7:22 PM, 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.
> -v2:
> Fix commit descriptions and further simplify the code
> as suggested by David Hildenbrand and John Hubbard.
Admin point: the above three lines will end up in the commit log,
which is probably not what you intended. If, instead, you put them
below the "---" line, then they will act as comments about
the patch, and won't show up in the commit log.
thanks,
--
John Hubbard
NVIDIA
>
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/mmap.c | 27 +++++++++++++--------------
> 1 file changed, 13 insertions(+), 14 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 4d4db76a07da..ff02c23fd375 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1276,26 +1276,25 @@ 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 anon_vma *anon_vma = NULL;
> struct vm_area_struct *near;
>
> + /* Try next first. */
> near = vma->vm_next;
> - if (!near)
> - goto try_prev;
> + if (near) {
> + anon_vma = reusable_anon_vma(near, vma, near);
> + if (anon_vma)
> + return anon_vma;
> + }
>
> - anon_vma = reusable_anon_vma(near, vma, near);
> - if (anon_vma)
> - return anon_vma;
> -try_prev:
> + /* Try prev next. */
> near = vma->vm_prev;
> - if (!near)
> - goto none;
> + if (near)
> + anon_vma = reusable_anon_vma(near, near, vma);
>
> - anon_vma = reusable_anon_vma(near, near, vma);
> - if (anon_vma)
> - return anon_vma;
> -none:
> /*
> + * 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,
> @@ -1303,7 +1302,7 @@ 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;
> }
>
> /*
>
