Re: [PATCH v2 3/6] mm/powerpc/8xx: constify ptep_get() argument

Pedro Falcato <[email protected]> Tue, 4 Aug 2026 13:38:52 +0100
Newsgroups gmane.linux.ports.ppc.embedded
Message-ID <anHc4aUbwxWx9YJF__34955.320767925$1785847161$gmane$org@pedro-suse>
On Tue, Aug 04, 2026 at 12:13:13PM +0100, Lorenzo Stoakes (ARM) wrote:
> On Mon, Aug 03, 2026 at 05:43:57PM +0100, Pedro Falcato wrote:
> > There is no need for write access to the PTE.
> >
> > Signed-off-by: Pedro Falcato <[email protected]>
> 
> With below addressed LGTM so:
> 
> Reviewed-by: Lorenzo Stoakes (ARM) <[email protected]>
> 
> > ---
> >  arch/powerpc/include/asm/nohash/32/pte-8xx.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
> > index e2ea8ba9f8ca..f2bab31040c7 100644
> > --- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h
> > +++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h
> > @@ -226,7 +226,7 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p
> >
> >  #ifdef CONFIG_PPC_16K_PAGES
> >  #define ptep_get ptep_get
> > -static inline pte_t ptep_get(pte_t *ptep)
> > +static inline pte_t ptep_get(const pte_t *ptep)
> >  {
> >  	pte_basic_t val = READ_ONCE(ptep->pte);
> >  	pte_t pte = {val, val, val, val};
> 
> Worth making these const too (that {val, val, val, val} horrifies me btw :)?

This is PPC code, so I don't know if they have any particular opinion here,
but I could definitely do this.

(FWIW, it seems we're more aggressive in MM in doing this than other places
in the kernel?)

-- 
Pedro