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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 1D88EC47082 for ; Thu, 3 Jun 2021 23:23:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECF12613AE for ; Thu, 3 Jun 2021 23:23:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229726AbhFCXZV (ORCPT ); Thu, 3 Jun 2021 19:25:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:53932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229675AbhFCXZV (ORCPT ); Thu, 3 Jun 2021 19:25:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 908D4613F9; Thu, 3 Jun 2021 23:23:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622762615; bh=vZ1xmVnHuzsQKfrQixTnvBSOe+G6brZcsOPAUugAzF8=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=UuONi5HOZd+gb0KU7ZxRmjOA/EtTPa5LxazaHT+y8wrMkIdeUEqK1yh3aVIoLOtt0 i5fZTB701rPVDzhkTiobN+PgqzOaDKWTTdd6cI5cDgLAnnIxhyf/Ad7w7R34jYhn0C mz2zX1LhaDt298fNmpadaa9KPYxLOGH6YdJeRT10lKbwOxmiNTujr95AI51ff8gWtY 1dZUC1h78tDlvAOw8A8Fs9CQVCO2ont4npY+oMlBIxMAY3akj4VuHM/aLl3+jr/kSg ToR/ecHFH8NPOzhcQ6j/JZMDBQvxmBOq01YXvZDEfz9MGhqE6Yj1Vb2CrvdUjearGx PygfauH3TLNpA== Date: Thu, 3 Jun 2021 18:23:34 -0500 From: Bjorn Helgaas To: Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= Cc: Bjorn Helgaas , Logan Gunthorpe , Joe Perches , Oliver O'Halloran , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Tyrel Datwyler , Russell Currey , Kurt Schwemmer , Vidya Sagar , Xiongfeng Wang , linux-pci@vger.kernel.org, Alex Williamson Subject: Re: [PATCH v6 5/6] PCI/sysfs: Only show value when driver_override is not NULL Message-ID: <20210603232334.GA2153375@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210603000112.703037-6-kw@linux.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+cc Alex, FYI] On Thu, Jun 03, 2021 at 12:01:11AM +0000, Krzysztof Wilczyński wrote: > Only expose the value of the "driver_override" variable through the > corresponding sysfs object when a value is actually set. This changes the attribute contents from "(null)" to an empty (zero-length) file when no driver override has been set. There are a few other driver_override_show() functions. Most don't check the pointer so they'll show "(null)". One (spi.c) checks and shows an empty string ("", file containing a single NULL character) instead of an empty (zero-length) file. > Signed-off-by: Krzysztof Wilczyński > Reviewed-by: Logan Gunthorpe > --- > drivers/pci/pci-sysfs.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 5d63df7c1820..4e9f582ca10f 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -580,10 +580,11 @@ static ssize_t driver_override_show(struct device *dev, > struct device_attribute *attr, char *buf) > { > struct pci_dev *pdev = to_pci_dev(dev); > - ssize_t len; > + ssize_t len = 0; > > device_lock(dev); > - len = sysfs_emit(buf, "%s\n", pdev->driver_override); > + if (pdev->driver_override) > + len = sysfs_emit(buf, "%s\n", pdev->driver_override); > device_unlock(dev); > return len; > } > -- > 2.31.1 >