From: Jeremy Fitzhardinge <jeremy@goop.org>
To: ohyama_sec@ariel-networks.com
Cc: linux-kernel@vger.kernel.org, the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [PATCH] x86 : omit duplicate processing at pte_pgprot()
Date: Sat, 15 Aug 2009 00:10:35 -0700 [thread overview]
Message-ID: <4A865F6B.20208@goop.org> (raw)
In-Reply-To: <20090809154312.62D1A378124@ns.ariel-networks.com>
On 08/09/09 08:43, ohyama_sec@ariel-networks.com wrote:
> I suggest following PATCH that omit duplicate processing of mask.
>
> pte_pgprot() macro [arch/x86/include/asm/pgtable.h] call pte_flags() [arch/x86/include/asm/pgtable_types.h] that return value is masked by PTE_FLAGS_MASK in pte_flags() function, and this macro also masks the returned value by PTE_FLAGS_MASK.
>
It probably won't make any difference in practice, because gcc will do a
common subexpression elimination for the "& PTE_FLAGS_MASK" between the
inline function and its caller. But it does tidy things up a bit.
> I guess that we don't have to do the mask processing at pte_pgprot() macro because it has already been masked at pte_flags().
> So, how about the following PATCH ?
>
> <Hiroyasu OHYAMA>
>
Please add a proper Signed-off-by: line.
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
J
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 3cc06e3..a0b454c 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -265,7 +265,7 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
> return __pgprot(preservebits | addbits);
> }
>
> -#define pte_pgprot(x) __pgprot(pte_flags(x) & PTE_FLAGS_MASK)
> +#define pte_pgprot(x) __pgprot(pte_flags(x))
>
> #define canon_pgprot(p) __pgprot(massage_pgprot(p))
> --
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>
next prev parent reply other threads:[~2009-08-15 7:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-09 15:43 [PATCH] x86 : omit duplicate processing at pte_pgprot() ohyama_sec
2009-08-15 7:10 ` Jeremy Fitzhardinge [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-08-15 18:46 ohyama_sec
2009-08-16 2:00 ohyama_sec
2009-08-16 2:01 ohyama_sec
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