From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751639AbbARMNi (ORCPT ); Sun, 18 Jan 2015 07:13:38 -0500 Received: from mail-gw2-out.broadcom.com ([216.31.210.63]:60903 "EHLO mail-gw2-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751143AbbARMNg (ORCPT ); Sun, 18 Jan 2015 07:13:36 -0500 X-IronPort-AV: E=Sophos;i="5.09,420,1418112000"; d="scan'208";a="55046981" Message-ID: <54BBA36A.10608@broadcom.com> Date: Sun, 18 Jan 2015 13:13:30 +0100 From: Arend van Spriel User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.24) Gecko/20111103 Lightning/1.0b2 Thunderbird/3.1.16 MIME-Version: 1.0 To: =?ISO-8859-1?Q?Uwe_Kleine-K=F6nig?= CC: Mark Rutland , , "Ian Campbell" , Florian Fainelli , Russell King , Pawel Moll , Scott Branden , Wolfram Sang , Ray Jui , Christian Daudt , , Matt Porter , Rob Herring , , , "Kumar Gala" , Grant Likely , Subject: Re: [PATCH v5 2/3] i2c: iproc: Add Broadcom iProc I2C Driver References: <1421451737-7107-1-git-send-email-rjui@broadcom.com> <1421451737-7107-3-git-send-email-rjui@broadcom.com> <54BB795C.6040402@broadcom.com> <20150118094741.GE22880@pengutronix.de> <20150118110658.GA1113@katana> <20150118111759.GG22880@pengutronix.de> <54BB9D2B.20408@broadcom.com> <20150118115650.GH22880@pengutronix.de> In-Reply-To: <20150118115650.GH22880@pengutronix.de> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/18/15 12:56, Uwe Kleine-König wrote: > Hello, > > On Sun, Jan 18, 2015 at 12:46:51PM +0100, Arend van Spriel wrote: >> On 01/18/15 12:17, Uwe Kleine-König wrote: >>> Hello Wolfram, >>> >>> On Sun, Jan 18, 2015 at 12:06:58PM +0100, Wolfram Sang wrote: >>>> On Sun, Jan 18, 2015 at 10:47:41AM +0100, Uwe Kleine-König wrote: >>>>> On Sun, Jan 18, 2015 at 10:14:04AM +0100, Arend van Spriel wrote: >>>>>> On 01/17/15 00:42, Ray Jui wrote: >>>>>>> + complete_all(&iproc_i2c->done); >>>>>> >>>>>> Looking over this code it seems to me there is always a single >>>>>> process waiting for iproc_i2c->done to complete. So using complete() >>>>>> here would suffice. >>>>> Yeah, there is always only a single thread waiting. That means both >>>>> complete and complete_all are suitable. AFAIK there is no reason to pick >>>>> one over the other in this case. >>>> >>>> Clarity? >>> And which do you consider more clear? complete_all might result in the >>> question: "Is there>1 waiter?" and complete might yield to "What about >>> the other waiters?". If you already know there is only one, both are on >>> par on clarity. Might only be me?! I don't care much. >> >> Maybe it is me, but it is not about questions but it is about >> implicit statements that the code makes (or reader derives from it). >> When using complete_all you indicate to the reader "there can be >> more than one waiter". When using complete it indicates "there is >> only one waiter". If those statements are not true that is a code > No, complete works just fine in the presence of>1 waiter. It just wakes > a single waiter and all others continue to wait. Yes. Agree. > That is, for single-waiter situations there is no semantic difference > between complete and complete_all. But there is a difference for > multi-waiter queues. Indeed. > I think this is just a matter of your POV in the single-waiter > situation: complete might be intuitive because you just completed a > single task and complete_all might be intuitive because it signals > "I'm completely done, there is noone waiting for me any more.". Ok. Let's leave it to the author's intuition or to say it differently "sorry for the noise" ;-) Regards, Arend > Best regards > Uwe >