linux-kernel - Re: [PATCHv2] remove unnecessary cache flush on v6 copypage

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Date:	Fri, 8 Jul 2011 10:35:42 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Heechul Yun <heechul@...inois.edu>
Cc:	Catalin Marinas <catalin.marinas@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	saeed.bishara@...il.com
Subject: Re: [PATCHv2] remove unnecessary cache flush on v6 copypage

On Thu, Jul 07, 2011 at 09:30:19AM -0500, Heechul Yun wrote:
> 
> ARM: mm: remove unnecessary cache flush on v6 copypage
> 
> Originally introduced to maintain coherency between icache and dcache
> in v6 nonaliasing mode. This is now handled by __sync_icache_dcache since
> c0177800, therefore unneceary in this function.  
> 
> Signed-off-by: Heechul Yun <heechul@...inois.edu>
> Acked-by: Catalin Marinas <catalin.marinas@....com>
> --
> arch/arm/mm/copypage-v6.c |    1 -
>  1 files changed, 0 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mm/copypage-v6.c b/arch/arm/mm/copypage-v6.c
> index bdba6c6..63cca00 100644
> --- a/arch/arm/mm/copypage-v6.c
> +++ b/arch/arm/mm/copypage-v6.c
> @@ -41,7 +41,6 @@ static void v6_copy_user_highpage_nonaliasing(struct page *to,
>  	kfrom = kmap_atomic(from, KM_USER0);
>  	kto = kmap_atomic(to, KM_USER1);
>  	copy_page(kto, kfrom);
> -	__cpuc_flush_dcache_area(kto, PAGE_SIZE);
>  	kunmap_atomic(kto, KM_USER1);
>  	kunmap_atomic(kfrom, KM_USER0);
>  }

The above patch is fine (it has tabs preserved) but the version in the
patch system has spaces instead (each space character has been replaced
with a '.') and so doesn't apply:

$ pdb getpatch 6995/1 |tr ' ' '.'
Patch:.6995/1:.mm:.remove.unnecessary.cache.flush.on.v6.copypage
From:.Heechul.Yun
-------------------------------------------------------------------------------
.arch/arm/mm/copypage-v6.c.|....1.-
.1.file.changed,.1.deletion(-)
-------------------------------------------------------------------------------
diff.--git.a/arch/arm/mm/copypage-v6.c.b/arch/arm/mm/copypage-v6.c
index.bdba6c6..63cca00.100644
---.a/arch/arm/mm/copypage-v6.c
+++.b/arch/arm/mm/copypage-v6.c
@@.-41,7.+41,6.@@.static.void.v6_copy_user_highpage_nonaliasing(struct.page.*to,........kfrom.=.kmap_atomic(from,.KM_USER0);
........kto.=.kmap_atomic(to,.KM_USER1);
........copy_page(kto,.kfrom);
-.......__cpuc_flush_dcache_area(kto,.PAGE_SIZE);
........kunmap_atomic(kto,.KM_USER1);
........kunmap_atomic(kfrom,.KM_USER0);
.}

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