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From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Michael Büsch" <m@bues.ch>
Cc: linux-wireless@vger.kernel.org, b43-dev@lists.infradead.org
Subject: (bug report) b43: impossible conditions in debugfs
Date: Thu, 26 Nov 2015 16:00:34 +0300	[thread overview]
Message-ID: <20151126130033.GG7289@mwanda> (raw)
In-Reply-To: <20151126133241.5bc5a793@wiggum>

On Thu, Nov 26, 2015 at 01:32:41PM +0100, Michael B?sch wrote:
> > See also:
> > drivers/net/wireless/broadcom/b43/debugfs.c:346 mmio32write__write_file() warn: impossible condition '(mask > 4294967295) => (0-u32max > u32max)'
> > drivers/net/wireless/broadcom/b43/debugfs.c:346 mmio32write__write_file() warn: impossible condition '(set > 4294967295) => (0-u32max > u32max)'
> 
> 
> 
> Sure. These are intentional.
> The compiler will optimize this out.

Hm...  We try to ignore when people do intentional comparisons with zero
like this:

	if (unsigned_var < 0 || unsigned_var >= 10)
		return -EINVAL;

Because they are obviously harmless and they don't hurt readability.
Also Linus doesn't like removing these.

But what's the point of this?  I have seen these before when I was
checking ide_set_disk_chs() for underflows.  I also reported another one
recently that was exactly the same as this and the guy changed it from
if (x > UINT_MAX) to if (!(x < UINT_MAX))...  I don't get it.

regards,
dan carpenter

  reply	other threads:[~2015-11-26 13:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-26 11:59 (bug report) b43: impossible conditions in debugfs Dan Carpenter
2015-11-26 12:32 ` Michael Büsch
2015-11-26 13:00   ` Dan Carpenter [this message]
2015-11-26 13:34     ` Michael Büsch

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