From patchwork Tue Feb 19 11:11:49 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 2162581 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 97E31DF24C for ; Tue, 19 Feb 2013 11:12:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932468Ab3BSLMl (ORCPT ); Tue, 19 Feb 2013 06:12:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57807 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932354Ab3BSLMk (ORCPT ); Tue, 19 Feb 2013 06:12:40 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r1JBCEFn008390 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 19 Feb 2013 06:12:14 -0500 Received: from localhost.localdomain (vpn1-4-162.gru2.redhat.com [10.97.4.162]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r1JBC8Dg017234 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Tue, 19 Feb 2013 06:12:10 -0500 Date: Tue, 19 Feb 2013 08:11:49 -0300 From: Mauro Carvalho Chehab To: Cc: Borislav Petkov , Greg KH , Linux Kernel Mailing List , Steven Rostedt , Frederic Weisbecker , Ingo Molnar , , , , , Doug Thompson , , , Subject: Re: SYSFS "errors" Message-ID: <20130219081149.46972f56@redhat.com> In-Reply-To: <20130219101121.GJ23197@arwen.pp.htv.fi> References: <20130218174916.GA2070@kroah.com> <20130218184633.GC10755@arwen.pp.htv.fi> <20130218164638.7cb53baa@redhat.com> <20130218200542.GB20137@arwen.pp.htv.fi> <20130218184742.5a4c3c06@redhat.com> <20130218215434.GB16794@kroah.com> <20130218221306.GA21493@pd.tnic> <20130218222618.GA21818@kroah.com> <20130218224405.GB21493@pd.tnic> <20130219070310.2cadad7a@redhat.com> <20130219101121.GJ23197@arwen.pp.htv.fi> Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Em Tue, 19 Feb 2013 12:11:21 +0200 Felipe Balbi escreveu: > Hi, > > On Tue, Feb 19, 2013 at 07:03:10AM -0300, Mauro Carvalho Chehab wrote: > > > But my gut feeling says to stay concervative and not touch this code - > > > we don't know what uses it and how much we would break by "fixing" it. > > > The current situation is not that big of a deal IMVHO and I'd be willing > > > to accept the small inconcistency versus possibly breaking userspace. > > > > I remember I saw some discussions about it in the past at bluesmoke ML, > > saying that -ENODEV is the expected behavior when this is not supported. > > > > Changing from -ENODEV to "N/A" will break anything that would be relying > > on the previous behavior. So, I think that such change will for sure break > > userspace. > > > > If we're willing to change it, not creating the "sdram_scrub_rate" sysfs > > node is less likely to affect userspace. > > yeah, I agree with this. Guess we shouldn't be creating files which > aren't supported by the underlying HW and having a read() return -ENODEV > is quite weird IMO since that's actually 'breaking' read() interface > although that's up to interpretations. The enclosed (untested) patch will likely do the trick. It needs to be tested with one of the drivers that support scrub setting (amd64_edac.c, cpc925_edac.c, e752x_edac.c, i5100_edac.c or i7core_edac.c). Regards, Mauro - [PATCH] edac: only create sdram_scrub_rate where supported Currently, sdram_scrub_rate sysfs node is created even if the device doesn't support get/set the scub rate. Change the logic to only create this device node when the operation is supported. Reported-by: Felipe Balbi Signed-off-by: Mauro Carvalho Chehab diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c index 9c58da6..937975b 100644 --- a/drivers/edac/edac_mc_sysfs.c +++ b/drivers/edac/edac_mc_sysfs.c @@ -7,7 +7,7 @@ * * Written Doug Thompson www.softwarebitmaker.com * - * (c) 2012 - Mauro Carvalho Chehab + * (c) 2012-2013 - Mauro Carvalho Chehab * The entire API were re-written, and ported to use struct device * */ @@ -681,9 +681,6 @@ static ssize_t mci_sdram_scrub_rate_store(struct device *dev, unsigned long bandwidth = 0; int new_bw = 0; - if (!mci->set_sdram_scrub_rate) - return -ENODEV; - if (strict_strtoul(data, 10, &bandwidth) < 0) return -EINVAL; @@ -707,9 +704,6 @@ static ssize_t mci_sdram_scrub_rate_show(struct device *dev, struct mem_ctl_info *mci = to_mci(dev); int bandwidth = 0; - if (!mci->get_sdram_scrub_rate) - return -ENODEV; - bandwidth = mci->get_sdram_scrub_rate(mci); if (bandwidth < 0) { edac_printk(KERN_DEBUG, EDAC_MC, "Error reading scrub rate\n"); @@ -882,7 +876,6 @@ static struct attribute *mci_attrs[] = { &dev_attr_ce_noinfo_count.attr, &dev_attr_ue_count.attr, &dev_attr_ce_count.attr, - &dev_attr_sdram_scrub_rate.attr, &dev_attr_max_location.attr, NULL }; @@ -1017,6 +1010,14 @@ int edac_create_sysfs_mci_device(struct mem_ctl_info *mci) return err; } + if (mci->set_sdram_scrub_rate && mci->get_sdram_scrub_rate) { + err = device_create_file(&mci->dev, + &dev_attr_sdram_scrub_rate); + if (err) { + edac_dbg(1, "failure: create sdram_scrub_rate\n"); + goto fail2; + } + } /* * Create the dimm/rank devices */ @@ -1061,6 +1062,7 @@ fail: continue; device_unregister(&dimm->dev); } +fail2: device_unregister(&mci->dev); bus_unregister(&mci->bus); kfree(mci->bus.name);