Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <bd7487c725e15b0c20612a44ecf301637a60c157.camel@perches.com>
Subject: Re: [PATCH] docs: deprecated.rst: Clarify open-coded arithmetic
 with literals
From:   Joe Perches <joe@perches.com>
To:     Len Baker <len.baker@gmx.com>, Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>
Cc:     "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
Date:   Fri, 27 Aug 2021 12:06:18 -0700
In-Reply-To: <20210827171226.2938-1-len.baker@gmx.com>
References: <20210827171226.2938-1-len.baker@gmx.com>
Content-Type: text/plain; charset="ISO-8859-1"
User-Agent: Evolution 3.40.0-1 
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

On Fri, 2021-08-27 at 19:12 +0200, Len Baker wrote:
> Although using literals for size calculation in allocator arguments may
> be harmless due to compiler warnings in case of overflows, it is better
> to refactor the code to avoid the use of open-coded math idiom.
> 
> So, clarify the preferred way in these cases.
[]
> diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst
[]
> @@ -60,7 +60,8 @@ smaller allocation being made than the caller was expecting. Using those
> ?allocations could lead to linear overflows of heap memory and other
> ?misbehaviors. (One exception to this is literal values where the compiler
> ?can warn if they might overflow. Though using literals for arguments as
> -suggested below is also harmless.)
> +suggested below is also harmless. So, the preferred way in these cases is
> +to refactor the code to keep the open-coded math idiom out.)

wordsmithing trivia:

'keep <foo> out' is difficult to parse as 'keep' is generally a positive
word but its meaning is later reversed with out.

'avoid <foo>' maybe be better phrasing.