linux-kernel - Re: [PATCH 5/7] omfs: add bitmap routines

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Date:	Sat, 29 Mar 2008 23:27:10 -0400
From:	Bob Copeland <me@...copeland.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 5/7] omfs: add bitmap routines

On Fri, Mar 28, 2008 at 04:51:10AM +0100, Arnd Bergmann wrote:
> On Thursday 27 March 2008, Bob Copeland wrote:
> 
> > +unsigned long omfs_count_free(struct super_block *sb)
> 
> I think it would be helpful to express this using hweight64.

Here's a version with hweight64:

+unsigned long omfs_count_free(struct super_block *sb)
+{
+	unsigned int i, j;
+	u64 *map;
+	unsigned long sum = 0;
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+
+	for (i = 0; i < sbi->s_imap_size; i++) {
+		map = (u64 *) sbi->s_imap[i];
+		for (j = 0; j < sb->s_blocksize / 8; j++)
+			sum += hweight64(~map[j]);
+	}
+	return sum;
+}

-- 
Bob Copeland %% www.bobcopeland.com 

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