Re: [PATCH v4 02/14] mm: Switch mm->get_unmapped_area() to a flag

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

On Mon, Mar 25, 2024 at 7:17 PM Rick Edgecombe
<rick.p.edgecombe@intel.com> wrote:
>
>
> diff --git a/mm/util.c b/mm/util.c
> index 669397235787..8619d353a1aa 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -469,17 +469,17 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
>
>         if (mmap_is_legacy(rlim_stack)) {
>                 mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
> -               mm->get_unmapped_area = arch_get_unmapped_area;
> +               clear_bit(MMF_TOPDOWN, &mm->flags);
>         } else {
>                 mm->mmap_base = mmap_base(random_factor, rlim_stack);
> -               mm->get_unmapped_area = arch_get_unmapped_area_topdown;
> +               set_bit(MMF_TOPDOWN, &mm->flags);
>         }
>  }
>  #elif defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
>  void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
>  {
>         mm->mmap_base = TASK_UNMAPPED_BASE;
> -       mm->get_unmapped_area = arch_get_unmapped_area;
> +       clear_bit(MMF_TOPDOWN, &mm->flags);
>  }
>  #endif

Makes sense to me.
Acked-by: Alexei Starovoitov <ast@kernel.org>
for the idea and for bpf bits.