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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 D60EAC43387 for ; Wed, 16 Jan 2019 17:30:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 994EB20675 for ; Wed, 16 Jan 2019 17:30:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linaro.org header.i=@linaro.org header.b="Myq5jeuQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727218AbfAPRa3 (ORCPT ); Wed, 16 Jan 2019 12:30:29 -0500 Received: from mail-it1-f196.google.com ([209.85.166.196]:38223 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727068AbfAPRa2 (ORCPT ); Wed, 16 Jan 2019 12:30:28 -0500 Received: by mail-it1-f196.google.com with SMTP id h65so3812651ith.3 for ; Wed, 16 Jan 2019 09:30:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Ljv1GR361GBRKYIkB7jsE2in05byxJjM9Of4H3Lyf7A=; b=Myq5jeuQiJRYN2ReKgBqC+F4WGXNyGRFDymPLmULSfQs2QRfD5K5Ahb63Z4mhTyh17 MpMjhQcqZG6hctg9oIL/rLUg29Xp1ba+aUzYzHmQv1/+g7orOEOrG19xW6nYHMEgpPEm J9EtBEv+x9wwEmBh8HQLRPHDaOeuSgyXrNhJs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Ljv1GR361GBRKYIkB7jsE2in05byxJjM9Of4H3Lyf7A=; b=KJ1wApqhU5+7XnPnsXgoxByzw25J0MY1jfI5HnqZZ5TzsgCB539HFovYtAjt2w05uh /r9NH1edsKbrnQp7vBhhiunDODfgFWJAReo5x2Z4pBoeJvDzugLESFWLmWoBhNrf4hCz wx6RMz3oH+JJe1VDnvHgbd3FW2WAplR4up9v3oWWFEJ0X7/0Seafu9PhT7ErtXOLisjW /9vuxjZ0ghIcVLnNgtpNZLXLYfbZRsNhXL6IBNp49QFzpyC720SvjDYiD7z8Gim15WKv dTkQP0V5JdUisi3r9pY5XwEppanDSs8ETEl2pLX00nSQayMN8G0Ks3Ni4M6WJE5QuV6C 1UpQ== X-Gm-Message-State: AJcUukck/dORv4+cZd0lDsymSoQjkmHNPBs3Oc61fFLeqSp+smkhIgJa wilQrJWaxjMXawqtNE4hbgk+EidZ88srU8aZEdIMdQ== X-Google-Smtp-Source: ALg8bN5ovBywmS2CY3P6+MGnjtlKbf7GdYn/0jnI7YCqLKMeYq51k91Eh0XXDHFIbC9usy4KjWsgWtsp6K1xpI+fWbM= X-Received: by 2002:a02:1b1d:: with SMTP id l29mr5818176jad.98.1547659826972; Wed, 16 Jan 2019 09:30:26 -0800 (PST) MIME-Version: 1.0 References: <20190115230742.13730-1-mathieu.poirier@linaro.org> <20190115230742.13730-3-mathieu.poirier@linaro.org> <20190116153948.GC871@kroah.com> <20190116163314.GB5446@kroah.com> <20190116171259.GB10164@kroah.com> In-Reply-To: <20190116171259.GB10164@kroah.com> From: Mathieu Poirier Date: Wed, 16 Jan 2019 10:30:16 -0700 Message-ID: Subject: Re: [PATCH 2/7] coresight: perf: Add "sinks" group to PMU directory To: Greg KH Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Alexander Shishkin , schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, Will Deacon , Mark Rutland , Jiri Olsa , Namhyung Kim , Adrian Hunter , ast@kernel.org, "H. Peter Anvin" , "Suzuki K. Poulose" , linux-s390@vger.kernel.org, Linux Kernel Mailing List , linux-arm-kernel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 16 Jan 2019 at 10:13, Greg KH wrote: > > On Wed, Jan 16, 2019 at 09:38:09AM -0700, Mathieu Poirier wrote: > > On Wed, 16 Jan 2019 at 09:33, Greg KH wrote: > > > > > > On Wed, Jan 16, 2019 at 09:14:33AM -0700, Mathieu Poirier wrote: > > > > On Wed, 16 Jan 2019 at 08:39, Greg KH wrote: > > > > > > > > > > On Tue, Jan 15, 2019 at 04:07:37PM -0700, Mathieu Poirier wrote: > > > > > > Add a "sinks" directory entry so that users can see all the sinks > > > > > > available in the system in a single place. Individual sink are added > > > > > > as they are registered with the coresight bus. > > > > > > > > > > > > Signed-off-by: Mathieu Poirier > > > > > > --- > > > > > > .../hwtracing/coresight/coresight-etm-perf.c | 43 +++++++++++++++++++ > > > > > > .../hwtracing/coresight/coresight-etm-perf.h | 1 + > > > > > > drivers/hwtracing/coresight/coresight.c | 17 ++++++++ > > > > > > 3 files changed, 61 insertions(+) > > > > > > > > > > > > diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c > > > > > > index f21eb28b6782..292bd409a68c 100644 > > > > > > --- a/drivers/hwtracing/coresight/coresight-etm-perf.c > > > > > > +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c > > > > > > @@ -14,6 +14,7 @@ > > > > > > #include > > > > > > #include > > > > > > #include > > > > > > +#include > > > > > > #include > > > > > > #include > > > > > > > > > > > > @@ -43,8 +44,18 @@ static const struct attribute_group etm_pmu_format_group = { > > > > > > .attrs = etm_config_formats_attr, > > > > > > }; > > > > > > > > > > > > +static struct attribute *etm_config_sinks_attr[] = { > > > > > > + NULL, > > > > > > +}; > > > > > > + > > > > > > +static const struct attribute_group etm_pmu_sinks_group = { > > > > > > + .name = "sinks", > > > > > > + .attrs = etm_config_sinks_attr, > > > > > > +}; > > > > > > + > > > > > > static const struct attribute_group *etm_pmu_attr_groups[] = { > > > > > > &etm_pmu_format_group, > > > > > > + &etm_pmu_sinks_group, > > > > > > NULL, > > > > > > }; > > > > > > > > > > > > @@ -479,6 +490,38 @@ int etm_perf_symlink(struct coresight_device *csdev, bool link) > > > > > > return 0; > > > > > > } > > > > > > > > > > > > +static ssize_t etm_perf_sink_name_show(struct device *dev, > > > > > > + struct device_attribute *dattr, > > > > > > + char *buf) > > > > > > +{ > > > > > > + /* See function coresight_sink_by_id() to know where this is used */ > > > > > > + u32 hash = hashlen_hash(hashlen_string(NULL, dattr->attr.name)); > > > > > > + > > > > > > + return scnprintf(buf, PAGE_SIZE, "%x\n", hash); > > > > > > +} > > > > > > + > > > > > > +int etm_perf_symlink_sink(struct coresight_device *csdev) > > > > > > +{ > > > > > > + struct device *pmu_dev = etm_pmu.dev; > > > > > > + struct device *pdev = csdev->dev.parent; > > > > > > + struct device_attribute *dev_attr; > > > > > > + > > > > > > + if (csdev->type != CORESIGHT_DEV_TYPE_SINK && > > > > > > + csdev->type != CORESIGHT_DEV_TYPE_LINKSINK) > > > > > > + return -EINVAL; > > > > > > + > > > > > > + if (!etm_perf_up) > > > > > > + return -EPROBE_DEFER; > > > > > > + > > > > > > + dev_attr = kzalloc(sizeof(*dev_attr), GFP_KERNEL); > > > > > > + dev_attr->attr.name = kstrdup(dev_name(pdev), GFP_KERNEL); > > > > > > + dev_attr->attr.mode = 0444; > > > > > > + dev_attr->show = etm_perf_sink_name_show; > > > > > > + > > > > > > + return sysfs_add_file_to_group(&pmu_dev->kobj, > > > > > > + &dev_attr->attr, "sinks"); > > > > > > > > > > What is so odd about this call that you needed me to review this? > > > > > > > > As far as I can tell nobody is feeding a dynamic struct attribute to > > > > the function and I wasn't sure if it was because they were told not to > > > > or simply because it wasn't needed, hence asking for a second opinion. > > > > > > Ah. Well, again, this is a good question to answer: > > > > > > > > And what happens if this call fails, do you leak memory? > > > > That's something I will fix in the next revision. > > > > > > > > And also, what happens when you unload the device, who frees the > > > attribute's memory? > > > > If configured, coresight devices aren't removable. > > But is the driver able to be unloaded? Unbound from the device manually > through sysfs? There's lots of ways devices are "removed" that don't > involved physical removal :) All drivers are built-in and thus preventing them from being unloaded. They also have their ".suppress_bin_attrs" field set to take care of unbinding through sysfs. > > thanks, > > greg k-h