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References: <20211119113644.1600-1-alx.manpages@gmail.com> <20211120130104.185699-1-alx.manpages@gmail.com>
 <20211120130104.185699-17-alx.manpages@gmail.com>
In-Reply-To: <20211120130104.185699-17-alx.manpages@gmail.com>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Sun, 21 Nov 2021 14:25:48 +0100
Message-ID: <CAK8P3a1svD_pog3-ZKnQAv=Li3=U9kB_ApXQOkzH-UCLtaQMEQ@mail.gmail.com>
Subject: Re: [PATCH v2 15/20] linux/compiler.h: Implement __must_be_array() in
 terms of __must_be()
To:     Alejandro Colomar <alx.manpages@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Kees Cook <keescook@chromium.org>,
        Joe Perches <joe@perches.com>
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Precedence: bulk

On Sat, Nov 20, 2021 at 2:00 PM Alejandro Colomar
<alx.manpages@gmail.com> wrote:

> @@ -255,7 +255,7 @@ static inline void *offset_to_ptr(const int *off)
>  #endif /* __ASSEMBLY__ */
>
>  /* &a[0] degrades to a pointer: a different type from an array */
> -#define __must_be_array(a)     BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
> +#define __must_be_array(a)  __must_be(!__same_type((a), &(a)[0]))

Please go the other way here and change all users of __must_be() to use
BUILD_BUG_ON_ZERO() or BUILD_BUG_ON() for consistency.

        Arnd