Re: [PATCH] overflow: Add __must_check attribute to check_*() helpers

From: Matthew Wilcox <willy@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Jason Gunthorpe <jgg@ziepe.ca>, Leon Romanovsky <leon@kernel.org>,
	linux-kernel@vger.kernel.org,
	kernel-hardening@lists.openwall.com
Subject: Re: [PATCH] overflow: Add __must_check attribute to check_*() helpers
Date: Thu, 13 Aug 2020 12:23:27 +0100	[thread overview]
Message-ID: <20200813112327.GF17456@casper.infradead.org> (raw)
In-Reply-To: <202008121450.405E4A3@keescook>

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().