From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sukadev Bhattiprolu Subject: Re: [RFC][PATCH] Implement ns_of_pid() Date: Tue, 11 Nov 2008 22:53:07 -0800 Message-ID: <20081112065307.GD27806@us.ibm.com> References: <20081112064139.GA27806@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20081112064139.GA27806-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Oleg Nesterov , "Eric W. Biederman" Cc: Containers , Pavel Emelyanov List-Id: containers.vger.kernel.org Oops, the subject should say [PATCH 1/3] I forward ported these patches from Eric's patchset and touch tested them again. I think we were in agreement on this set. Should we push these 3 patches upstream (after some more testing). Sukadev Sukadev Bhattiprolu [sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org] wrote: | | From: Sukadev Bhattiprolu | Date: Mon, 10 Nov 2008 19:03:56 -0800 | Subject: [PATCH 1/3] 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 |