linux-kernel - Re: [PATCH v2 02/10] minixfs: use memweight()

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Message-ID: <20120604102623.GE7670@quack.suse.cz>
Date:	Mon, 4 Jun 2012 12:26:23 +0200
From:	Jan Kara <jack@...e.cz>
To:	Akinobu Mita <akinobu.mita@...il.com>
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v2 02/10] minixfs: use memweight()

On Sat 02-06-12 22:40:08, Akinobu Mita wrote:
> Use memweight() to count the total number of bits clear in memory area.
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
> Cc: linux-fsdevel@...r.kernel.org
> ---
> 
> No changes from v1
> 
>  fs/minix/bitmap.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c
> index 4bc50da..564f1a5 100644
> --- a/fs/minix/bitmap.c
> +++ b/fs/minix/bitmap.c
> @@ -29,10 +29,8 @@ static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 num
>  	unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
>  
>  	while (blocks--) {
> -		unsigned words = blocksize / 2;
> -		__u16 *p = (__u16 *)(*map++)->b_data;
> -		while (words--)
> -			sum += 16 - hweight16(*p++);
> +		sum += blocksize * BITS_PER_BYTE -
> +			memweight((*map++)->b_data, blocksize);
  Hmm, just using bitmap_weight() should be fine here as well AFAICS...

								Honza
-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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