The patch titled
pid: implement ns_of_pid
has been removed from the -mm tree. Its filename was
pid-implement-ns_of_pid.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: pid: implement ns_of_pid
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
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 <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Bastian Blank <bastian@xxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Nadia Derbey <Nadia.Derbey@xxxxxxxx>
Acked-by: Serge Hallyn <serue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pid.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff -puN include/linux/pid.h~pid-implement-ns_of_pid include/linux/pid.h
--- a/include/linux/pid.h~pid-implement-ns_of_pid
+++ a/include/linux/pid.h
@@ -123,6 +123,24 @@ extern struct pid *alloc_pid(struct pid_
extern void free_pid(struct pid *pid);
/*
+ * ns_of_pid() returns the pid namespace in which the specified pid was
+ * allocated.
+ *
+ * NOTE:
+ * ns_of_pid() is expected to be called for a process (task) that has
+ * an attached 'struct pid' (see attach_pid(), detach_pid()) i.e @pid
+ * is expected to be non-NULL. If @pid is NULL, caller should handle
+ * the resulting NULL pid-ns.
+ */
+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
*
* pid_nr() : global id, i.e. the id seen from the init namespace;
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
origin.patch
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