Re: [PATCH 06/10] parse_integer: convert mm/

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 06/10] parse_integer: convert mm/
Date: Mon, 04 May 2015 16:33:12 +0200	[thread overview]
Message-ID: <878ud4if9z.fsf@rasmusvillemoes.dk> (raw)
In-Reply-To: <20150502005535.GF21655@p183.telecom.by> (Alexey Dobriyan's message of "Sat, 2 May 2015 03:55:35 +0300")

On Sat, May 02 2015, Alexey Dobriyan <adobriyan@gmail.com> wrote:

> Convert mm/ directory away from deprecated simple_strto*() interface.
>
> One thing to note about parse_integer() and seemingly useless casts --
> range of accepted values depends on result type.
>
> 	int val;
> 	parse_integer(s, 0, &val);
>
> will accept negative integers, while
>
> 	int val;
> 	parse_integer(s, 0, (unsigned int *)&val);
>
> will accept only 0 and positive integers.

... and then silently write a negative value to val if the parsed
integer happens to be larger than INT_MAX.

Again, I think passing cast expressions to parse_integer should be
verboten.

In these particular cases:

* memtest_pattern should just be unsigned int - it's only ever used as
  such anyway, and it represents a count.

* hashdist should be a boolean, but even in its current form, there's no
  reason to not just use parse_integer as-is. If people like to set it
  by passing -42 just let them.

Rasmus