Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751739AbdFTBjU (ORCPT ); Mon, 19 Jun 2017 21:39:20 -0400 Received: from mail-pg0-f43.google.com ([74.125.83.43]:35500 "EHLO mail-pg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751058AbdFTBjS (ORCPT ); Mon, 19 Jun 2017 21:39:18 -0400 MIME-Version: 1.0 In-Reply-To: <87y3snajd2.fsf@rasmusvillemoes.dk> References: <20170619135418.8580-1-haolee.swjtu@gmail.com> <87y3snajd2.fsf@rasmusvillemoes.dk> From: Hao Lee Date: Tue, 20 Jun 2017 09:39:17 +0800 Message-ID: Subject: Re: [PATCH] mm: remove a redundant condition in the for loop To: Rasmus Villemoes Cc: Vlastimil Babka , akpm@linux-foundation.org, mgorman@techsingularity.net, mhocko@suse.com, Johannes Weiner , iamjoonsoo.kim@lge.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 725 Lines: 20 On Tue, Jun 20, 2017 at 3:05 AM, Rasmus Villemoes wrote: > On Mon, Jun 19 2017, Vlastimil Babka wrote: > >> On 06/19/2017 03:54 PM, Hao Lee wrote: >>> The variable current_order decreases from MAX_ORDER-1 to order, so the >>> condition current_order <= MAX_ORDER-1 is always true. >>> >>> Signed-off-by: Hao Lee >> >> Sounds right. >> >> Acked-by: Vlastimil Babka > > current_order and order are both unsigned, and if order==0, > current_order >= order is always true, and we may decrement > current_order past 0 making it UINT_MAX... A comment would be in order, > though. Thanks, I didn't notice unsigned subtraction. Sorry about that.