linux-kernel - Re: [PATCH] bitmap: simplify GENMASK(size

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Date:   Tue, 26 Oct 2021 18:10:55 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Qian Cai <quic_qiancai@...cinc.com>
Cc:     Yury Norov <yury.norov@...il.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] bitmap: simplify GENMASK(size - 1, 0) lines

On Tue, Oct 26, 2021 at 10:41:08AM -0400, Qian Cai wrote:
> Since "size" is an "unsigned int", the rvalue "size - 1" will still be
> "unsigned int" according to the C standard (3.2.1.5 Usual arithmetic
> conversions). Therefore, GENMASK(size - 1, 0) will always return 0UL.

Huh?!

Have you run test_bitmap et al., btw?

-- 
With Best Regards,
Andy Shevchenko