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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 22 Aug 2022 11:45:39 -0700
Message-ID: <CAHk-=wjqkWEr0MRO5hWuBoTDgNUj4qQK8V_Y36et=61mdPztJw@mail.gmail.com>
Subject: Re: [for-linus][PATCH 01/10] tracing: Suppress sparse warnings
 triggered by is_signed_type()
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
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On Mon, Aug 22, 2022 at 11:20 AM Bart Van Assche <bvanassche@acm.org> wrote:
>
> I agree that it's better that sparse sees the same code as what is used to
> build the kernel. However, I do not agree that the patch above is a solution.
> Sparse reports a warning for the suggested definition above of is_signed_type()
> because the new definition tries to use the less-than (<) operator to compare
> two __bitwise types.

Argh. I forgot that part. It wasn't just the cast that warned, it was
the compare too.

But we did have a sparse fix for it, didn't we? That fix required that
the '< (type)1' cast be changed to '<= (type)0' iirc, and a patch to
sparse, but it at least avoided the problem.

          Linus