linux-kernel - Re: [PATCH v2 1/4] kernel.h: Implement DIV_ROUND_CLOSEST

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Message-ID: <20150324142926.GF17049@unpythonic.net>
Date:	Tue, 24 Mar 2015 09:29:27 -0500
From:	Jeff Epler <jepler@...ythonic.net>
To:	Javi Merino <javi.merino@....com>
Cc:	akpm@...ux-foundation.org, intel-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	emil.l.velikov@...il.com, daniel@...ll.ch,
	Jani Nikula <jani.nikula@...ux.intel.com>,
	David Airlie <airlied@...ux.ie>,
	Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH v2 1/4] kernel.h: Implement DIV_ROUND_CLOSEST_ULL

[for just patch 1/4; I didn't look as closely at the others]
Reviewed-by: Jeff Epler <jepler@...ythonic.net>

...with one half of a caveat (rounded up?): Like most or all of the
originals, and like DIV_ROUND_CLOSEST just above it in kernel.h, the new
code gives an incorrect answer if the temporary overflows at
+	unsigned long long _tmp = (x) + (__d) / 2;

As a doc improvement a remark could be added to a number of these
functions, but there's little reason for that to be part of this series.

Jeff
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