linux-kernel - Re: [PATCH v2] powerpc/64s: Rewrite __real_pte() and __rpte_to

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Message-ID: <87ldvfvoa8.fsf@gmail.com>
Date: Mon, 13 Jan 2025 00:43:19 +0530
From: Ritesh Harjani (IBM) <ritesh.list@...il.com>
To: Christophe Leroy <christophe.leroy@...roup.eu>, Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, Naveen N Rao <naveen@...nel.org>, Madhavan Srinivasan <maddy@...ux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>, linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v2] powerpc/64s: Rewrite __real_pte() and __rpte_to_hidx() as static inline

Christophe Leroy <christophe.leroy@...roup.eu> writes:

> Rewrite __real_pte() and __rpte_to_hidx() as static inline in order to
> avoid following warnings/errors when building with 4k page size:
>
> 	  CC      arch/powerpc/mm/book3s64/hash_tlb.o
> 	arch/powerpc/mm/book3s64/hash_tlb.c: In function 'hpte_need_flush':
> 	arch/powerpc/mm/book3s64/hash_tlb.c:49:16: error: variable 'offset' set but not used [-Werror=unused-but-set-variable]
> 	   49 |         int i, offset;
> 	      |                ^~~~~~
>
> 	  CC      arch/powerpc/mm/book3s64/hash_native.o
> 	arch/powerpc/mm/book3s64/hash_native.c: In function 'native_flush_hash_range':
> 	arch/powerpc/mm/book3s64/hash_native.c:782:29: error: variable 'index' set but not used [-Werror=unused-but-set-variable]
> 	  782 |         unsigned long hash, index, hidx, shift, slot;
> 	      |                             ^~~~~
>
> Reported-by: kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202501081741.AYFwybsq-lkp@intel.com/
> Fixes: ff31e105464d ("powerpc/mm/hash64: Store the slot information at the right offset for hugetlb")
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> ---
> v2: Also inline __rpte_to_hidx() for the same reason

Thanks for addressing the other warning too in v2. I also tested the
changes on my system and this fixes both the reported warnings.

The changes looks good to me. Please feel free to add - 

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>


> ---
>  arch/powerpc/include/asm/book3s/64/hash-4k.h | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
> index c3efacab4b94..aa90a048f319 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
> @@ -77,9 +77,17 @@
>  /*
>   * With 4K page size the real_pte machinery is all nops.
>   */
> -#define __real_pte(e, p, o)		((real_pte_t){(e)})
> +static inline real_pte_t __real_pte(pte_t pte, pte_t *ptep, int offset)
> +{
> +	return (real_pte_t){pte};
> +}
> +
>  #define __rpte_to_pte(r)	((r).pte)
> -#define __rpte_to_hidx(r,index)	(pte_val(__rpte_to_pte(r)) >> H_PAGE_F_GIX_SHIFT)
> +
> +static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index)
> +{
> +	return pte_val(__rpte_to_pte(rpte)) >> H_PAGE_F_GIX_SHIFT;
> +}
>  
>  #define pte_iterate_hashed_subpages(rpte, psize, va, index, shift)       \
>  	do {							         \
> -- 
> 2.47.0