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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 B476BC432C0 for ; Sun, 24 Nov 2019 18:41:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9881120748 for ; Sun, 24 Nov 2019 18:41:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726962AbfKXSlF (ORCPT ); Sun, 24 Nov 2019 13:41:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:60504 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726851AbfKXSlF (ORCPT ); Sun, 24 Nov 2019 13:41:05 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 24BA1B2AA; Sun, 24 Nov 2019 18:41:02 +0000 (UTC) Date: Sun, 24 Nov 2019 19:40:59 +0100 From: Michal =?iso-8859-1?Q?Such=E1nek?= To: Sourabh Jain Cc: linux-doc@vger.kernel.org, mahesh@linux.vnet.ibm.com, corbet@lwn.net, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, hbathini@linux.ibm.com Subject: Re: [PATCH v3 2/4] powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files Message-ID: <20191124184059.GP11661@kitsune.suse.cz> References: <20191109122339.20484-1-sourabhjain@linux.ibm.com> <20191109122339.20484-3-sourabhjain@linux.ibm.com> <20191109125933.GF1384@kitsune.suse.cz> <8c1ec297-0c34-12de-2528-be436697215a@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8c1ec297-0c34-12de-2528-be436697215a@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 16, 2019 at 08:07:29PM +0530, Sourabh Jain wrote: > > > On 11/9/19 6:29 PM, Michal Suchánek wrote: > > On Sat, Nov 09, 2019 at 05:53:37PM +0530, Sourabh Jain wrote: > >> As the number of FADump sysfs files increases it is hard to manage all of > >> them inside /sys/kernel directory. It's better to have all the FADump > >> related sysfs files in a dedicated directory /sys/kernel/fadump. But in > >> order to maintain the backward compatibility the /sys/kernel/fadump_* > >> sysfs files are replicated inside /sys/kernel/fadump/ and eventually get > >> removed in future. > >> > >> As the FADump sysfs files are now part of dedicated directory there is no > >> need to prefix their name with fadump_, hence sysfs file names are also > >> updated. For example fadump_enabled sysfs file is now referred as enabled. > >> > >> Also consolidate ABI documentation for all the FADump sysfs files in a > >> single file Documentation/ABI/testing/sysfs-kernel-fadump. > >> > >> Signed-off-by: Sourabh Jain > >> --- > >> Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++ > >> arch/powerpc/kernel/fadump.c | 38 +++++++++++++++++ > >> arch/powerpc/platforms/powernv/opal-core.c | 10 +++-- > >> 3 files changed, 86 insertions(+), 3 deletions(-) > >> create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump > >> > >> diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump > >> new file mode 100644 > >> index 000000000000..a77f1a5ba389 > >> --- /dev/null > >> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump > >> @@ -0,0 +1,41 @@ > >> +What: /sys/kernel/fadump/* > >> +Date: Nov 2019 > >> +Contact: linuxppc-dev@lists.ozlabs.org > >> +Description: > >> + The /sys/kernel/fadump/* is a collection of FADump sysfs > >> + file provide information about the configuration status > >> + of Firmware Assisted Dump (FADump). > >> + > >> +What: /sys/kernel/fadump/enabled > >> +Date: Nov 2019 > >> +Contact: linuxppc-dev@lists.ozlabs.org > >> +Description: read only > >> + Primarily used to identify whether the FADump is enabled in > >> + the kernel or not. > >> +User: Kdump service > >> + > >> +What: /sys/kernel/fadump/registered > >> +Date: Nov 2019 > >> +Contact: linuxppc-dev@lists.ozlabs.org > >> +Description: read/write > >> + Helps to control the dump collect feature from userspace. > >> + Setting 1 to this file enables the system to collect the > >> + dump and 0 to disable it. > >> +User: Kdump service > >> + > >> +What: /sys/kernel/fadump/release_mem > >> +Date: Nov 2019 > >> +Contact: linuxppc-dev@lists.ozlabs.org > >> +Description: write only > >> + This is a special sysfs file and only available when > >> + the system is booted to capture the vmcore using FADump. > >> + It is used to release the memory reserved by FADump to > >> + save the crash dump. > >> + > >> +What: /sys/kernel/fadump/release_opalcore > >> +Date: Nov 2019 > >> +Contact: linuxppc-dev@lists.ozlabs.org > >> +Description: write only > >> + The sysfs file is available when the system is booted to > >> + collect the dump on OPAL based machine. It used to release > >> + the memory used to collect the opalcore. > >> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c > >> index ed59855430b9..a9591def0c84 100644 > >> --- a/arch/powerpc/kernel/fadump.c > >> +++ b/arch/powerpc/kernel/fadump.c > >> @@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private) > >> return 0; > >> } > >> > >> +struct kobject *fadump_kobj; > >> +EXPORT_SYMBOL_GPL(fadump_kobj); > >> + > >> static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem, > >> 0200, NULL, > >> fadump_release_memory_store); > >> @@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered, > >> 0644, fadump_register_show, > >> fadump_register_store); > >> > >> +static struct kobj_attribute release_attr = __ATTR(release_mem, > >> + 0200, NULL, > >> + fadump_release_memory_store); > >> +static struct kobj_attribute enable_attr = __ATTR(enabled, > >> + 0444, fadump_enabled_show, > >> + NULL); > >> +static struct kobj_attribute register_attr = __ATTR(registered, > >> + 0644, fadump_register_show, > >> + fadump_register_store); > >> + > >> DEFINE_SHOW_ATTRIBUTE(fadump_region); > >> > >> static void fadump_init_files(void) > >> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void) > >> struct dentry *debugfs_file; > >> int rc = 0; > >> > >> + fadump_kobj = kobject_create_and_add("fadump", kernel_kobj); > >> + if (!fadump_kobj) { > >> + pr_err("failed to create fadump kobject\n"); > >> + return; > >> + } > >> rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr); > >> if (rc) > >> printk(KERN_ERR "fadump: unable to create sysfs file" > >> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void) > >> printk(KERN_ERR "fadump: unable to create sysfs file" > >> " fadump_release_mem (%d)\n", rc); > >> } > >> + /* Replicating the following sysfs attributes under FADump kobject. > >> + * > >> + * - fadump_enabled -> enabled > >> + * - fadump_registered -> registered > >> + * - fadump_release_mem -> release_mem > >> + */ > >> + rc = sysfs_create_file(fadump_kobj, &enable_attr.attr); > >> + if (rc) > >> + pr_err("unable to create enabled sysfs file (%d)\n", > >> + rc); > >> + rc = sysfs_create_file(fadump_kobj, ®ister_attr.attr); > >> + if (rc) > >> + pr_err("unable to create registered sysfs file (%d)\n", > >> + rc); > >> + if (fw_dump.dump_active) { > >> + rc = sysfs_create_file(fadump_kobj, &release_attr.attr); > >> + if (rc) > >> + pr_err("unable to create release_mem sysfs file (%d)\n", > >> + rc); > >> + } > >> return; > >> } > > Hello, > > > > I’m so sorry for taking this long to write you back. > > > wouldn't it make more sense to create the files in the new location and > > add a symlink at the old location? > > There are APIs which allow to create a symlink for an entire kobject but > I did not find a way to create symlink of an individual sysfs file. > > Do you have any approach in mind to achieve the same? There is at least one example of plain symlink: find /sys -type l -xtype f /sys/kernel/security/evm If there is no interface to do one sanely duplicationg the files is better than nothing. Thanks Michal