Re: [PATCH 2/4] mm/mprotect: move softleaf code out of the main function

David Hildenbrand (Arm)
2026-03-19T21:33:57Z

On 3/19/26 19:31, Pedro Falcato wrote:
> Move softleaf change_pte_range code into a separate function. This makes
> the change_pte_range() function (or where it inlines) a good bit
> smaller. Plus it lessens cognitive load when reading through the
> function.
>
> Signed-off-by: Pedro Falcato <pfalcato@suse.de>
> ---
> mm/mprotect.c | 128 +++++++++++++++++++++++++++-----------------------
> 1 file changed, 68 insertions(+), 60 deletions(-)
>
> diff --git a/mm/mprotect.c b/mm/mprotect.c
> index 1bd0d4aa07c2..8d4fa38a8a26 100644
> --- a/mm/mprotect.c
> +++ b/mm/mprotect.c
> @@ -211,6 +211,73 @@ static void set_write_prot_commit_flush_ptes(struct vm_area_struct *vma,
> commit_anon_folio_batch(vma, folio, page, addr, ptep, oldpte, ptent, nr_ptes, tlb);
> }
>
> +static noinline long change_pte_softleaf(struct vm_area_struct *vma,

Why the noinline? This sounds like something that works good on some
CPUs and bad on others, no?

I like the cleanup, but the noinline really is odd.

> + unsigned long addr, pte_t *pte, pte_t oldpte, unsigned long cp_flags)

I'd call that "change_softleaf_pte"

> +{
> + bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
> + bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;

both can be const.

> + softleaf_t entry = softleaf_from_pte(oldpte);
> + pte_t newpte;
> +

[...]

--
Cheers,

David