Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751940AbaAODq4 (ORCPT ); Tue, 14 Jan 2014 22:46:56 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:36042 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751499AbaAODqz (ORCPT ); Tue, 14 Jan 2014 22:46:55 -0500 Message-ID: <52D604A7.9000204@huawei.com> Date: Wed, 15 Jan 2014 11:46:47 +0800 From: Ding Tianhong User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Veaceslav Falico , CC: , , Subject: Re: [RFC] sysfs_rename_link() and its usage References: <20140114171740.GB1867@redhat.com> In-Reply-To: <20140114171740.GB1867@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.22.246] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014/1/15 1:17, Veaceslav Falico wrote: > Hi, > > I'm hitting a strange issue and/or I'm completely lost in sysfs internals. > > Consider having two net_device *a, *b; which are registered normally. > Now, to create a link from /sys/class/net/a->name/linkname to b, one should > use: > > sysfs_create_link(&(a->dev.kobj), &(b->dev.kobj), linkname); > > To remove it, even simpler: > > sysfs_remove_link(&(a->dev.kobj), linkname); > > This works like a charm. However, if I want to use (obviously, with the > symlink present): > > sysfs_rename_link(&(a->dev.kobj), &(b->dev.kobj), oldname, newname); > > this fails with: > > "sysfs: ns invalid in 'a->name' for 'oldname'" > > in > > 608 struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, > ... > 615 if (!!sysfs_ns_type(parent_sd) != !!ns) { > 616 WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", > 617 sysfs_ns_type(parent_sd) ? "required" : "invalid", > 618 parent_sd->s_name, name); > 619 return NULL; > 620 } > > Code path: > warn_slowpath_fmt+0x46/0x50 > sysfs_get_dirent_ns+0x30/0x80 > sysfs_find_dirent+0x84/0x110 > sysfs_get_dirent_ns+0x3e/0x80 > sysfs_rename_link_ns+0x54/0xd0 > > I have no idea what this code means. Is there any reason for it to > fail (i.e. am I doing something wrong?) or I've hit a bug? > > I've tested the only user of it (bridge) - and it works fine, however it's > not using its own net_device's kobject but rather its own dir. > I use the sysfs_rename_link(x,x) and meet the same problem, I review the code for bridge, I found the br->ifobj was using kobject_create_and_add() to add a subdir for this, maybe it helps? Ding > Thank you! > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/