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

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Message-ID: <4afd7242-a8f9-6d41-e1a8-e6cfbe3cea6e@quicinc.com>
Date:   Wed, 27 Oct 2021 11:06:53 -0400
From:   Qian Cai <quic_qiancai@...cinc.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
CC:     Yury Norov <yury.norov@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] bitmap: simplify GENMASK(size - 1, 0) lines



On 10/27/21 5:44 AM, Andy Shevchenko wrote:
> Agree, but you see a problem here, W=2, for example, is high due to
> a lot of non-sense (or very little sense) noise. The warning you got
> is hidden on purpose. On top of that, the code has not been thought
> through at all, despite missed test run. This is easy to catch.
> 
> What I expect from "a stranger" who is in doubt (obviously) how this
> code works to ask and then decide how to act.
> 
> And on top of all these, we used to have UMN case which makes me
> first think of bad experiments on the community (I really haven't
> believed that this patch was sent consciously).
> 
> So, please be careful next time and better ask first before acting,
> if in doubt.

Yes, I am an idiot. My brain was short-circled for a moment to be
totally mistaken with "GENMASK() == 0" instead GENMASK_INPUT_CHECK(). I
am not sure how to avoid those short-circles again in the future though
apart from thinking about going to an office in the near future, so kids
at home would drive my less crazy. Of course, I knew the trick for
lib_test.c now which should help me in this subsystem in the future.
Thanks for your time, Andy.