Re: [PATCH 1/3] s390/mm: Drop all pxdp_get()

[Heiko Carstens <hca@linux.ibm.com>]

On Wed, Sep 23, 2026 at 10:02:20AM +0530, Anshuman Khandual wrote:
> Current platform specific pxdp_get() helpers are exact same as the default
> ones defined in the generic MM header (include/linux/pgtable.h) thus making
> them redundant. Just add required forward declarations.
> 
> Cc: Alexander Gordeev <agordeev@linux.ibm.com>
> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
> Cc: linux-s390@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-mm@kvack.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  arch/s390/include/asm/pgtable.h | 35 +++++----------------------------
>  1 file changed, 5 insertions(+), 30 deletions(-)
> 
> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
> index e882663a58e77..0a0b0ec42b624 100644
> --- a/arch/s390/include/asm/pgtable.h
> +++ b/arch/s390/include/asm/pgtable.h
> @@ -25,6 +25,11 @@
>  #include <asm/page.h>
>  #include <asm/uv.h>
>  
> +static inline pte_t ptep_get(const pte_t *ptep);
> +static inline pud_t pudp_get(const pud_t *pudp);
> +static inline p4d_t p4dp_get(const p4d_t *p4dp);
> +static inline pgd_t pgdp_get(const pgd_t *pgdp);
> +
>  extern pgd_t swapper_pg_dir[];
>  extern pgd_t invalid_pg_dir[];
>  extern void paging_init(void);
> @@ -985,36 +990,6 @@ static inline void set_pte(pte_t *ptep, pte_t pte)
>  	WRITE_ONCE(*ptep, pte);
>  }
>  
> -#define ptep_get ptep_get
> -static inline pte_t ptep_get(pte_t *ptep)
> -{
> -	return READ_ONCE(*ptep);
> -}

As reported by Sashiko, this results in a compile error due to conflicting
types; but I don't see too much value with this patch if a forward declaration
of the common code implementation needs to be added instead. Looks like s390
would be the only architecture which would have that.

Besides that the s390 implementation of ptep_get() will be filled with
more content "soon", when Alexander's lazy mmu work will be merged.