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Date: Wed, 7 Oct 2015 07:53:20 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Michael Cree <mcree@orcon.net.nz>, Matt Turner <mattst88@gmail.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Borislav Petkov <bp@alien8.de>, linux-alpha@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 2/3] word-at-a-time.h: support zero_bytemask() on
 alpha and tile
Message-ID: <20151007055320.GA27737@gmail.com>
References: <1444159429-4788-1-git-send-email-cmetcalf@ezchip.com>
 <1444159429-4788-3-git-send-email-cmetcalf@ezchip.com>
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* Chris Metcalf <cmetcalf@ezchip.com> wrote:

> Both alpha and tile needed implementations of zero_bytemask.
> 
> The alpha version is untested.
> 
> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
> ---
>  arch/alpha/include/asm/word-at-a-time.h | 2 ++
>  arch/tile/include/asm/word-at-a-time.h  | 8 +++++++-
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/alpha/include/asm/word-at-a-time.h b/arch/alpha/include/asm/word-at-a-time.h
> index 6b340d0f1521..902e6ab00a06 100644
> --- a/arch/alpha/include/asm/word-at-a-time.h
> +++ b/arch/alpha/include/asm/word-at-a-time.h
> @@ -52,4 +52,6 @@ static inline unsigned long find_zero(unsigned long bits)
>  #endif
>  }
>  
> +#define zero_bytemask(mask) ((2ul << (find_zero(mask) * 8)) - 1)

Small nit: please use a proper C inline function instead of CPP, as for example 
the PowerPC zero_bytemask() function is.

> -/* Generate 0x01 byte values for non-zero bytes using a SIMD instruction. */
> +/* Generate 0x01 byte values for zero bytes using a SIMD instruction. */
>  static inline unsigned long has_zero(unsigned long val, unsigned long *data,
>  				     const struct word_at_a_time *c)
>  {
> @@ -33,4 +33,10 @@ static inline long find_zero(unsigned long mask)
>  #endif
>  }
>  
> +#ifdef __BIG_ENDIAN
> +#define zero_bytemask(mask) (~1ul << (63 - __builtin_clzl(mask)))
> +#else
> +#define zero_bytemask(mask) ((2ul << __builtin_ctzl(mask)) - 1)
> +#endif

Ditto.

Other than that, for the whole series:

  Reviewed-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo