Re: [PATCH v3 29/40] mm: drop some redundant checks around hugetlb VMAs

[Zi Yan]

On Thu Sep 17, 2026 at 12:22 PM EDT, Lorenzo Stoakes (ARM) wrote:
> Adjust code which inadvertently perform redundant checks on hugetlb VMAs
> and clean them up:
>
> * hugetlb VMAs have VMA_DONTEXPAND_BIT set so a VMA_SPECIAL_FLAGS check
>   suffices. (migrate_vma_setup() regains an explicit hugetlb test later in
>   the series, once VMA_SPECIAL_FLAGS is removed.)
>
> * hugetlb VMAs unconditionally set vma->vm_ops, so they are never
>   anonymous.
>
> * hugetlb VMAs do not set VMA_PFNMAP_BIT so checking for this is redundant.
>
> While we're here also drop a VM_BUG_ON() which the simplified check above
> makes unreachable, and use the new VMA flag API.
>
> No functional change intended.
>
> Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
> ---
>  arch/arm64/kvm/mmu.c         | 4 +---
>  drivers/gpu/drm/drm_gpusvm.c | 3 +--
>  mm/migrate_device.c          | 4 ++--
>  3 files changed, 4 insertions(+), 7 deletions(-)
>
Makes sense.

Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>


-- 
Best Regards,
Yan, Zi