On Thu, Jul 04, 2024 at 02:27:04PM GMT, Liam R. Howlett wrote:
> Extract clean up of failed munmap() operations from
> do_vmi_align_munmap(). This simplifies later patches in the series.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> ---
> mm/mmap.c | 25 ++++++++++++++++++++-----
> 1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 28a46d9ddde0..d572e1ff8255 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -2586,6 +2586,25 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
> vma->vm_userfaultfd_ctx, anon_vma_name(vma));
> }
>
> +/*
> + * abort_munmap_vmas - Undo any munmap work and free resources
> + *
> + * Reattach detached vmas, free up maple tree used to track the vmas.
> + */
> +static inline void abort_munmap_vmas(struct ma_state *mas_detach)
> +{
> + struct vm_area_struct *vma;
> + int limit;
> +
> + limit = mas_detach->index;
This feels like a change to existing behaviour actually, I mean a sensible
one - as you are not just walking the tree start-to-end but rather only
walking up to the point that it has been populated (assuming I'm not
missing anything, looks to me like mas_for_each is _inclusive_ on max).
Maybe worth mentioning in commit msg?
> + mas_set(mas_detach, 0);
> + /* Re-attach any detached VMAs */
> + mas_for_each(mas_detach, vma, limit)
> + vma_mark_detached(vma, false);
> +
> + __mt_destroy(mas_detach->tree);
> +}
> +
> /*
> * do_vmi_align_munmap() - munmap the aligned region from @start to @end.
> * @vmi: The vma iterator
> @@ -2740,11 +2759,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
> userfaultfd_error:
> munmap_gather_failed:
> end_split_failed:
> - mas_set(&mas_detach, 0);
> - mas_for_each(&mas_detach, next, end)
> - vma_mark_detached(next, false);
> -
> - __mt_destroy(&mt_detach);
> + abort_munmap_vmas(&mas_detach);
> start_split_failed:
> map_count_exceeded:
> validate_mm(mm);
> --
> 2.43.0
>
This looks fine though, feel free to add:
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
