From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F2D0C433F5 for ; Mon, 27 Aug 2018 20:55:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B669C20880 for ; Mon, 27 Aug 2018 20:55:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B669C20880 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727309AbeH1Anf (ORCPT ); Mon, 27 Aug 2018 20:43:35 -0400 Received: from mail.bootlin.com ([62.4.15.54]:52357 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726958AbeH1Anf (ORCPT ); Mon, 27 Aug 2018 20:43:35 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id CA34A2079D; Mon, 27 Aug 2018 22:55:18 +0200 (CEST) Received: from localhost (unknown [88.191.26.124]) by mail.bootlin.com (Postfix) with ESMTPSA id 9E1A520719; Mon, 27 Aug 2018 22:55:18 +0200 (CEST) Date: Mon, 27 Aug 2018 22:55:17 +0200 From: Alexandre Belloni To: Jia-Ju Bai , johan@kernel.org, j-keerthy@ti.com Cc: a.zummo@towertech.it, linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] rtc: rtc-omap: Replace mdelay() with msleep() in omap_rtc_power_off() Message-ID: <20180827205517.GD24549@piout.net> References: <20180730135314.9336-1-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180730135314.9336-1-baijiaju1990@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 30/07/2018 21:53:14+0800, Jia-Ju Bai wrote: > omap_rtc_power_off() is never called in atomic context. > It calls mdelay() to busily wait, which is not necessary. > mdelay() can be replaced with msleep(). > > This is found by a static analysis tool named DCNS written by myself. > > Signed-off-by: Jia-Ju Bai > --- > drivers/rtc/rtc-omap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c > index 39086398833e..ef3d09525d0f 100644 > --- a/drivers/rtc/rtc-omap.c > +++ b/drivers/rtc/rtc-omap.c > @@ -476,7 +476,7 @@ static void omap_rtc_power_off(void) > * power off the system. Add a 500 ms margin for external latencies > * (e.g. debounce circuits). > */ > - mdelay(2500); > + msleep(2500); I'm not sure about that one because this is a poweroff function so it doesn't really make sense to sleep versus busy waiting (all the drivers in power/reset use mdelay()) -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com