Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751369AbdFETvS (ORCPT ); Mon, 5 Jun 2017 15:51:18 -0400 Received: from mga14.intel.com ([192.55.52.115]:17445 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209AbdFETvQ (ORCPT ); Mon, 5 Jun 2017 15:51:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,302,1493708400"; d="scan'208";a="111173745" From: Ross Zwisler To: linux-kernel@vger.kernel.org Cc: Ross Zwisler , "Anaczkowski, Lukasz" , "Box, David E" , "Kogut, Jaroslaw" , "Lahtinen, Joonas" , "Moore, Robert" , "Nachimuthu, Murugasamy" , "Odzioba, Lukasz" , "Rafael J. Wysocki" , "Rafael J. Wysocki" , "Schmauss, Erik" , "Verma, Vishal L" , "Zheng, Lv" , Dan Williams , Dave Hansen , Greg Kroah-Hartman , Len Brown , Tim Chen , devel@acpica.org, linux-acpi@vger.kernel.org, linux-nvdimm@lists.01.org Subject: [resend RFC 5/6] sysfs: add sysfs_add_group_link() Date: Mon, 5 Jun 2017 13:50:56 -0600 Message-Id: <20170605195057.31492-6-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 2.9.4 In-Reply-To: <20170605195057.31492-1-ross.zwisler@linux.intel.com> References: <20170602205956.28351-1-ross.zwisler@linux.intel.com> <20170605195057.31492-1-ross.zwisler@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4392 Lines: 115 The current __compat_only_sysfs_link_entry_to_kobj() code allows us to create symbolic links in sysfs to groups or attributes. Something like: /sys/.../entry1/groupA -> /sys/.../entry2/groupA This patch extends this functionality with a new sysfs_add_group_link() call that allows the link to have a different name than the group or attribute, so: /sys/.../entry1/link_name -> /sys/.../entry2/groupA __compat_only_sysfs_link_entry_to_kobj() now just calls sysfs_add_group_link(), passing in the same name for both the group/attribute and for the link name. This is needed by the ACPI HMAT enabling work because we want to have a group of performance attributes that live in a memory target. This group represents the performance between the (initiator,target) pair, and in the target the attribute group is named "via_mem_initX" to represent this pairing: # tree mem_tgt2/via_mem_init0/ mem_tgt2/via_mem_init0/ ├── mem_init0 -> ../../mem_init0 ├── mem_tgt2 -> ../../mem_tgt2 ├── read_bw_MBps ├── read_lat_nsec ├── write_bw_MBps └── write_lat_nsec We then want to link to this attribute group from the initiator, but change the name to "via_mem_tgtX" since we're now looking at it from the initiator's perspective: # ls -l mem_init0/via_mem_tgt2 lrwxrwxrwx. 1 root root 0 Jun 1 10:00 mem_init0/via_mem_tgt2 -> ../mem_tgt2/via_mem_init0 Signed-off-by: Ross Zwisler --- fs/sysfs/group.c | 30 +++++++++++++++++++++++------- include/linux/sysfs.h | 2 ++ 2 files changed, 25 insertions(+), 7 deletions(-) diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index ac2de0e..19db57c8 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -367,15 +367,15 @@ void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name, EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group); /** - * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing - * to a group or an attribute + * sysfs_add_group_link - add a symlink to a kobject pointing to a group or + * an attribute * @kobj: The kobject containing the group. * @target_kobj: The target kobject. * @target_name: The name of the target group or attribute. + * @link_name: The name of the link to the target group or attribute. */ -int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, - struct kobject *target_kobj, - const char *target_name) +int sysfs_add_group_link(struct kobject *kobj, struct kobject *target_kobj, + const char *target_name, const char *link_name) { struct kernfs_node *target; struct kernfs_node *entry; @@ -400,12 +400,28 @@ int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, return -ENOENT; } - link = kernfs_create_link(kobj->sd, target_name, entry); + link = kernfs_create_link(kobj->sd, link_name, entry); if (IS_ERR(link) && PTR_ERR(link) == -EEXIST) - sysfs_warn_dup(kobj->sd, target_name); + sysfs_warn_dup(kobj->sd, link_name); kernfs_put(entry); kernfs_put(target); return IS_ERR(link) ? PTR_ERR(link) : 0; } +EXPORT_SYMBOL_GPL(sysfs_add_group_link); + +/** + * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing + * to a group or an attribute + * @kobj: The kobject containing the group. + * @target_kobj: The target kobject. + * @target_name: The name of the target group or attribute. + */ +int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, + struct kobject *target_kobj, + const char *target_name) +{ + return sysfs_add_group_link(kobj, target_kobj, target_name, + target_name); +} EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index c6f0f0d..865f499 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -278,6 +278,8 @@ int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name, struct kobject *target, const char *link_name); void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name, const char *link_name); +int sysfs_add_group_link(struct kobject *kobj, struct kobject *target_kobj, + const char *target_name, const char *link_name); int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, struct kobject *target_kobj, const char *target_name); -- 2.9.4