Re: [PATCH] powerpc/mm/hash: Code cleanup

[Kunwu Chan]

On 2024/1/25 21:47, Aneesh Kumar K.V wrote:
> On 1/25/24 3:16 PM, Kunwu Chan wrote:
> > This part was commented in about 17 years before.
> > If there are no plans to enable this part code in the future,
> > we can remove this dead code.
> >
> > Signed-off-by: Kunwu Chan <chentao@xxxxxxxxxx>
> > ---
> >   arch/powerpc/include/asm/book3s/64/mmu-hash.h | 22 -------------------
> >   1 file changed, 22 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> > index 1c4eebbc69c9..d39ec7134a78 100644
> > --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> > +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
> > @@ -731,26 +731,6 @@ struct hash_mm_context {
> >   #endif /* CONFIG_PPC_SUBPAGE_PROT */
> >   };
> >   
> > -#if 0
> > -/*
> > - * The code below is equivalent to this function for arguments
> > - * < 2^VSID_BITS, which is all this should ever be called
> > - * with.  However gcc is not clever enough to compute the
> > - * modulus (2^n-1) without a second multiply.
> > - */
> > -#define vsid_scramble(protovsid, size) \
> > -	((((protovsid) * VSID_MULTIPLIER_##size) % VSID_MODULUS_##size))
> > -
> > -/* simplified form avoiding mod operation */
> > -#define vsid_scramble(protovsid, size) \
> > -	({								 \
> > -		unsigned long x;					 \
> > -		x = (protovsid) * VSID_MULTIPLIER_##size;		 \
> > -		x = (x >> VSID_BITS_##size) + (x & VSID_MODULUS_##size); \
> > -		(x + ((x+1) >> VSID_BITS_##size)) & VSID_MODULUS_##size; \
> > -	})
> > -
> > -#else /* 1 */
> >   static inline unsigned long vsid_scramble(unsigned long protovsid,
> >   				  unsigned long vsid_multiplier, int vsid_bits)
> >   {
> > @@ -764,8 +744,6 @@ static inline unsigned long vsid_scramble(unsigned long protovsid,
> >   	return (vsid + ((vsid + 1) >> vsid_bits)) & vsid_modulus;
> >   }
> >   
> > -#endif /* 1 */
> > -
> >   /* Returns the segment size indicator for a user address */
> >   static inline int user_segment_size(unsigned long addr)
> >   {
>
> That was done to make sure one can follow the actual compiled code better.
Thanks for your explanation. It's my bad.
> -aneesh
--
Thanks,
  Kunwu