From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [PATCH] net: Revert "fib_trie: use seq_file_net rather than seq->private" Date: Wed, 04 Jun 2014 16:11:46 -0600 Message-ID: <538F99A2.2090102@gmail.com> References: <1401919352-32263-1-git-send-email-sasha.levin@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Sasha Levin , davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net Return-path: In-Reply-To: <1401919352-32263-1-git-send-email-sasha.levin@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 6/4/14, 4:02 PM, Sasha Levin wrote: > This reverts commit 30f38d2fdd79f13fc929489f7e6e517b4a4bfe63. > > fib_triestat is surrounded by a big lie: while it claims that it's a > seq_file (fib_triestat_seq_open, fib_triestat_seq_show), it isn't: > > static const struct file_operations fib_triestat_fops = { > .owner = THIS_MODULE, > .open = fib_triestat_seq_open, > .read = seq_read, > .llseek = seq_lseek, > .release = single_release_net, > }; > > Yes, fib_triestat is just a regular file. > > A small detail (assuming CONFIG_NET_NS=y) is that while for seq_files > you could do seq_file_net() to get the net ptr, doing so for a regular > file would be wrong and would dereference an invalid pointer. > > The fib_triestat lie claimed a victim, and trying to show the file would > be bad for the kernel. This patch just reverts the issue and fixes > fib_triestat, which still needs a rewrite to either be a seq_file or > stop claiming it is. It worked fine for me. fib_triestat_seq_open() is a wrapper to single_open_net() which sets the namespace as the private element (returned by get_proc_net). If CONFIG_NETNS is not set: - single_open_net essentially sets file->private to init_net which is also what is returned by seq_file_net If CONFIG_NETNS is set, all is fine. What am I missing? David