linux-kernel - Re: [PATCH] async_tx: use memchr

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Date:	Mon, 29 Oct 2012 10:23:43 +0530
From:	Vinod Koul <vkoul@...radead.org>
To:	Akinobu Mita <akinobu.mita@...il.com>
Cc:	vinod.koul@...el.com, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org, Dan Williams <djbw@...com>
Subject: Re: [PATCH] async_tx: use memchr_inv

On Sun, 2012-10-28 at 00:49 +0900, Akinobu Mita wrote:
> Use memchr_inv() to check the specified page is filled with zero.
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
> Cc: Vinod Koul <vinod.koul@...el.com>
> Cc: Dan Williams <djbw@...com>
> ---
Looks fine to me, need Dan;s ack before applying

>  crypto/async_tx/async_xor.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
> index 154cc84..8ade0a0 100644
> --- a/crypto/async_tx/async_xor.c
> +++ b/crypto/async_tx/async_xor.c
> @@ -230,9 +230,7 @@ EXPORT_SYMBOL_GPL(async_xor);
>  
>  static int page_is_zero(struct page *p, unsigned int offset, size_t len)
>  {
> -	char *a = page_address(p) + offset;
> -	return ((*(u32 *) a) == 0 &&
> -		memcmp(a, a + 4, len - 4) == 0);
> +	return !memchr_inv(page_address(p) + offset, 0, len);
>  }
>  
>  static inline struct dma_chan *


-- 
Vinod Koul
Intel Corp.

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