Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754105AbYKZDpI (ORCPT ); Tue, 25 Nov 2008 22:45:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753073AbYKZDo5 (ORCPT ); Tue, 25 Nov 2008 22:44:57 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:36475 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956AbYKZDo4 (ORCPT ); Tue, 25 Nov 2008 22:44:56 -0500 Date: Tue, 25 Nov 2008 19:44:42 -0800 From: Sukadev Bhattiprolu To: oleg@redhat.com, ebiederm@xmission.com, roland@redhat.com Cc: daniel@hozac.com, xemul@openvz.org, containers@lists.osdl.org, linux-kernel@vger.kernel.org, sukadev@us.ibm.com Subject: [RFC][PATCH 1/5] pid: Implement ns_of_pid Message-ID: <20081126034442.GA23238@us.ibm.com> References: <20081126034242.GA23120@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081126034242.GA23120@us.ibm.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1895 Lines: 56 >From f3dd53544a8a7a1c43009f686cbadec561e5a489 Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Mon, 10 Nov 2008 19:03:56 -0800 Subject: [PATCH 1/5] pid: Implement ns_of_pid A current problem with the pid namespace is that it is easy to do pid related work after exit_task_namespaces which drops the nsproxy pointer. However if we are doing pid namespace related work we are always operating on some struct pid which retains the pid_namespace pointer of the pid namespace it was allocated in. So provide ns_of_pid which allows us to find the pid namespace a pid was allocated in. Using this we have the needed infrastructure to do pid namespace related work at anytime we have a struct pid, removing the chance of accidentally having a NULL pointer dereference when accessing current->nsproxy. Signed-off-by: Eric W. Biederman --- include/linux/pid.h | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/include/linux/pid.h b/include/linux/pid.h index d7e98ff..e9aec85 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -122,6 +122,17 @@ int next_pidmap(struct pid_namespace *pid_ns, int last); extern struct pid *alloc_pid(struct pid_namespace *ns); extern void free_pid(struct pid *pid); +/* ns_of_pid returns the pid namespace in which the specified + * pid was allocated. + */ +static inline struct pid_namespace *ns_of_pid(struct pid *pid) +{ + struct pid_namespace *ns = NULL; + if (pid) + ns = pid->numbers[pid->level].ns; + return ns; +} + /* * the helpers to get the pid's id seen from different namespaces * -- 1.5.2.5 -- 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/