Re: [Drbd-dev] [PATCH 13/13] DRBD: Fix comparison always false warning due to long/long long compare

From: Philipp Reisner
Date: Thu Oct 13 2011 - 04:25:45 EST


Am Mittwoch, 12. Oktober 2011, 15:35:28 schrieb Geert Uytterhoeven:
> On Wed, Oct 12, 2011 at 14:27, Philipp Reisner
>
> <philipp.reisner@xxxxxxxxxx> wrote:
> > From: David Howells <dhowells@xxxxxxxxxx>
> >
> > Fix warnings of the following nature in the drbd header:
> >
> > In file included from drivers/block/drbd/drbd_bitmap.c:32:
> > drivers/block/drbd/drbd_int.h: In function 'drbd_get_syncer_progress':
> > drivers/block/drbd/drbd_int.h:2234: warning: comparison is always false
> > due to limited range of data
> >
> > where mdev->rs_total (an unsigned long) is being compared to 1ULL << 32,
> > which is always false on a 32-bit machine.
>
> But on 32-bit, unsigned long is never larger than UINT_MAX neither, so
> it doesn't
> really change anything??
>

Hi Geert,

As the commit message says, David's intention was to silence a compiler
warning, not to change anything.

Best,
Phil
--
: Dipl-Ing Philipp Reisner
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