From: Andi Kleen <ak@suse.de>
To: David Chinner <dgc@sgi.com>
Cc: xfs@oss.sgi.com, cattelan@thebarn.com
Subject: Re: [PATCH] Replace XFS bit functions with Linux functions
Date: Tue, 2 Oct 2007 15:35:14 +0200 [thread overview]
Message-ID: <200710021535.14973.ak@suse.de> (raw)
In-Reply-To: <20071002125923.GH995458@sgi.com>
> One thing that is notable here is that the XFS code returns
> -1 if no bits are set. fls/fls64 return 0 in the same case, so
> the magic "- 1" will make them behave the same. however, it
> appears that find_first_bit() will return the number of bits
> searched. That might leave us with som nasty, non-obvious error
> cases....
See the changelog:
The semantics of the Linux functions differ a little, but i checked
all call sites that they can deal with that.
>
> Also, I don't really like the fact it requires sprinkling magic "-
> 1" adjustments to the return value of the replacement functions. If
> that is the way the functions work and relate to the XFS bitmaps,
Not all callers use them as bitmap indexes, some also use them as true log2s.
I also eliminated some + 1s.
Whatever you do it's not the same for all.
-Andi
next prev parent reply other threads:[~2007-10-02 13:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-02 8:10 [PATCH] Replace XFS bit functions with Linux functions Andi Kleen
2007-10-02 9:55 ` Christoph Hellwig
2007-10-02 10:11 ` Andi Kleen
2007-10-02 12:59 ` David Chinner
2007-10-02 13:35 ` Andi Kleen [this message]
2007-10-02 16:37 ` Russell Cattelan
2007-10-03 17:58 ` Andi Kleen
2007-10-03 18:20 ` Russell Cattelan
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