linux-kernel - Re: [PATCH] overflow: Add __must_check attribute to check

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Message-ID: <20200813112327.GF17456@casper.infradead.org>
Date:   Thu, 13 Aug 2020 12:23:27 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     Kees Cook <keescook@...omium.org>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Leon Romanovsky <leon@...nel.org>,
        linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com
Subject: Re: [PATCH] overflow: Add __must_check attribute to check_*() helpers

On Wed, Aug 12, 2020 at 02:51:52PM -0700, Kees Cook wrote:
> +/*
> + * Allows to effectively us apply __must_check to a macro so we can have
> + * both the type-agnostic benefits of the macros while also being able to
> + * enforce that the return value is, in fact, checked.
> + */
> +static inline bool __must_check __must_check_bool(bool condition)
> +{
> +	return unlikely(condition);
> +}

I'm fine with the concept, but this is a weirdly-generically-named
function that has a very specific unlikely() in it.  So I'd call
this __must_check_overflow() and then it's obvious that overflow is
unlikely(), whereas it's not obvious that __must_check_bool() is going
to be unlikely().