From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id 89989280442 for ; Wed, 6 Sep 2017 12:05:18 -0400 (EDT) Received: by mail-oi0-f71.google.com with SMTP id f138so10115646oih.1 for ; Wed, 06 Sep 2017 09:05:18 -0700 (PDT) Received: from sender-pp-091.zoho.com (sender-pp-091.zoho.com. [135.84.80.236]) by mx.google.com with ESMTPS id o62si88792oif.352.2017.09.06.09.05.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Sep 2017 09:05:17 -0700 (PDT) Subject: Re: [PATCH 1/1] workqueue: use type int instead of bool to index array References: <59AF6CB6.4090609@zoho.com> <20170906143320.GK1774378@devbig577.frc2.facebook.com> From: zijun_hu Message-ID: Date: Thu, 7 Sep 2017 00:04:59 +0800 MIME-Version: 1.0 In-Reply-To: <20170906143320.GK1774378@devbig577.frc2.facebook.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: zijun_hu@htc.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , jiangshanlai@gmail.com On 2017/9/6 22:33, Tejun Heo wrote: > Hello, > > On Wed, Sep 06, 2017 at 11:34:14AM +0800, zijun_hu wrote: >> From: zijun_hu >> >> type bool is used to index three arrays in alloc_and_link_pwqs() >> it doesn't look like conventional. >> >> it is fixed by using type int to index the relevant arrays. > > bool is a uint type which can be either 0 or 1. I don't see what the > benefit of this patch is.q > bool is NOT a uint type now, it is a new type introduced by gcc, it is rather different with "typedef int bool" historically see following code segments for more info about type bool bool v = 0x10; printf("v = %d\n", v); the output is v = 1. it maybe cause a invalid array index if bool is represented as uint bool highpri = wq->flags & WQ_HIGHPRI; WQ_HIGHPRI = 1 << 4, @highpri maybe 16, but the number of array elements is 2. bool is a logic value, the valid value is true or false. indexing array by type bool is not a good program custom it is more extendable to use type int, type bool maybe is improper if the number of array elements is extended to more than 2 in future besides, the relevant array is indexed by type int in many other places of the same source file. this patch can keep consistency > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org