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    SubjectRe: [Drbd-dev] [PATCH 13/13] DRBD: Fix comparison always false warning due to long/long long compare
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    On Thu, Oct 13, 2011 at 10:25, Philipp Reisner
    <philipp.reisner@linbit.com> wrote:
    > Am Mittwoch, 12. Oktober 2011, 15:35:28 schrieb Geert Uytterhoeven:
    >> On Wed, Oct 12, 2011 at 14:27, Philipp Reisner
    >> <philipp.reisner@linbit.com> wrote:
    >> > From: David Howells <dhowells@redhat.com>
    >> >
    >> > 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??
    >
    > As the commit message says, David's intention was to silence a compiler
    > warning, not to change anything.

    Sure, but
    1) Is the comparison a bug on 32-bit?
    2) I don't see a reason why (a different version of) gcc won't give
    a warning for the
    new comparison always being false.

    Gr{oetje,eeting}s,

                            Geert

    --
    Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

    In personal conversations with technical people, I call myself a hacker. But
    when I'm talking to journalists I just say "programmer" or something like that.
                                    -- Linus Torvalds
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