Date: Thu, 23 Jun 2011 14:13:17 -0400
From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>,
        Maarten Lankhorst <m.b.lankhorst@gmail.com>,
        Alex Elder <aelder@sgi.com>, xfs-masters@oss.sgi.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        xfs@oss.sgi.com
Subject: Re: [PATCH v2] xfs: Silence bounds checking compiler warning
Message-ID: <20110623181317.GA26945@infradead.org>
References: <4E037001.8090306__42924.0493024283$1308849791$gmane$org@gmail.com>
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 <20110623175533.GK11521@ZenIV.linux.org.uk>
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On Thu, Jun 23, 2011 at 06:55:33PM +0100, Al Viro wrote:
> ... and even better is to write in real C and have u8 name[]; in the
> end of your structure.  That's the standard C99 for this kind of thing
> (see 6.7.2.1p2, p16).  Zero-sized array is a gccism predating standard
> flexible array members and since the standard syntax is accepted by
> any gcc version that might be recent enough to build the kernel...

The situation is even more nasty - the one sized fake flex-array
actually is in the middle of the structure.  Besides sizeof-expressions
taking the one member array into account only members before the
variable sized array are used.  I've started a series cleaning up the
few structures that were done that way (for whatever reason), but it's
pretty intrusive.  I don't think papering over these warnings at this
point is a good idea.

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