Re: [PATCH 33/38] mm/memblock.c: remove invalid check

From: Andrew Morton
Date: Mon Sep 21 2015 - 17:31:09 EST


On Mon, 21 Sep 2015 15:34:05 +0200 Andrzej Hajda <a.hajda@xxxxxxxxxxx> wrote:

> Unsigned value cannot be lesser than zero.
>
> The problem has been detected using proposed semantic patch
> scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].
>
> [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576
>
> ...
>
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -837,7 +837,7 @@ void __init_memblock __next_reserved_mem_region(u64 *idx,
> {
> struct memblock_type *type = &memblock.reserved;
>
> - if (*idx >= 0 && *idx < type->cnt) {
> + if (*idx < type->cnt) {

Linus has in the past expressed a preference for retaining checks such
as this. iirc he finds it clearer. And perhaps safer if the type
should change in the future.


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