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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 50093ECDE3D for ; Thu, 18 Oct 2018 01:45:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E52821470 for ; Thu, 18 Oct 2018 01:45:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E52821470 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=perches.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 S1727425AbeJRJoN (ORCPT ); Thu, 18 Oct 2018 05:44:13 -0400 Received: from smtprelay0054.hostedemail.com ([216.40.44.54]:59321 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727082AbeJRJoM (ORCPT ); Thu, 18 Oct 2018 05:44:12 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay05.hostedemail.com (Postfix) with ESMTP id B09C718029586; Thu, 18 Oct 2018 01:45:41 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: laugh19_143359c92415c X-Filterd-Recvd-Size: 4292 Received: from XPS-9350 (unknown [172.58.22.135]) (Authenticated sender: joe@perches.com) by omf04.hostedemail.com (Postfix) with ESMTPA; Thu, 18 Oct 2018 01:45:38 +0000 (UTC) Message-ID: Subject: Re: [PATCH 1/3] driver core: add probe_err log helper From: Joe Perches To: Russell King - ARM Linux , Andy Shevchenko Cc: Andrzej Hajda , "Rafael J. Wysocki" , Greg Kroah-Hartman , Bartlomiej Zolnierkiewicz , Linux Kernel Mailing List , Javier Martinez Canillas , Mark Brown , linux-arm Mailing List , Marek Szyprowski Date: Wed, 17 Oct 2018 18:45:36 -0700 In-Reply-To: <20181017112914.GH30658@n2100.armlinux.org.uk> References: <20181016072244.1216-1-a.hajda@samsung.com> <20181016072244.1216-2-a.hajda@samsung.com> <605bd00e-ed0d-4259-bdc3-1784b2b3b16a@samsung.com> <20181016125543eucas1p1f23b3482179a9cd465f509e0abf782c1~eGAecmAv93038330383eucas1p1j@eucas1p1.samsung.com> <20181017112914.GH30658@n2100.armlinux.org.uk> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.1-1build1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2018-10-17 at 12:29 +0100, Russell King - ARM Linux wrote: > On Tue, Oct 16, 2018 at 04:55:00PM +0300, Andy Shevchenko wrote: > > On Tue, Oct 16, 2018 at 3:55 PM Andrzej Hajda wrote: > > > On 16.10.2018 13:29, Andrzej Hajda wrote: > > > > On 16.10.2018 13:01, Andy Shevchenko wrote: > > > > > On Tue, Oct 16, 2018 at 10:22 AM Andrzej Hajda wrote: > > > > > > During probe every time driver gets resource it should usually check for error > > > > > > printk some message if it is not -EPROBE_DEFER and return the error. This > > > > > > pattern is simple but requires adding few lines after any resource acquisition > > > > > > code, as a result it is often omited or implemented only partially. > > > > > > probe_err helps to replace such code seqences with simple call, so code: > > > > > > if (err != -EPROBE_DEFER) > > > > > > dev_err(dev, ...); > > > > > > return err; > > > > > > becomes: > > > > > > return probe_err(dev, err, ...); > > > > > > + va_start(args, fmt); > > > > > > + > > > > > > + vaf.fmt = fmt; > > > > > > + vaf.va = &args; > > > > > > + > > > > > > + __dev_printk(KERN_ERR, dev, &vaf); > > > > > It would be nice to print an error code as well, wouldn't it? > > > > Hmm, on probe fail error is printed anyway (with exception of > > > > EPROBE_DEFER, ENODEV and ENXIO): > > > > "probe of %s failed with error %d\n" > > > > On the other side currently some drivers prints the error code anyway > > > > via dev_err or similar, so I guess during conversion to probe_err it > > > > should be removed then. > > > > > > > > If we add error code to probe_err is it OK to report it this way? > > > > dev_err(dev, "%V, %d\n", &vaf, err); > > > > > > Ups, I forgot that message passed to probe_err will contain already > > > newline character. > > > > You may consider not to pass it. > > It's normal to pass the '\n', so by doing this, we create the situation > where this function becomes the exception to the norm. That's not a > good idea - we will see people forget that appending '\n' should not > be done for this particular function. > > While we could add a checkpatch rule, that's hassle (extra rework). It would not be a simple checkpatch rule with high confidence because of pr_cont uses that may not be in the patch context. > In I think the message would be much better formatted if we did: > > dev_err(dev, "error %d: %V", err, &vaf); s/%V/%pV/