Subject: Define/use task_active_pid_ns() wrapper
From: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
A process is visible in one or more pid namespaces, as it is known by
some pid_t in every ancestor pid namespace. Every time the process
forks, the child process also gets a pid_t in every ancestor pid
namespace.
While a process is visible in >=1 pid namespaces, it can see pid_t's
in only one pid namespace. We call this pid namespace it's "active
pid namespace", and it is always the youngest pid namespace in which
the process is known.
This patch defines/uses a wrapper to find the active pid namespace of a
process. The implementation of the wrapper will be changed in subsequent
patches when support for multiple pid namespaces are added.
Changelog:
2.6.21-rc6-mm1:
- Rename task_pid_ns() to task_active_pid_ns() to reflect that
a process can have multiple pid namespaces.
Signed-off-by: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
---
fs/exec.c | 2 +-
fs/proc/proc_misc.c | 3 ++-
include/linux/pid_namespace.h | 7 ++++++-
kernel/exit.c | 5 +++--
kernel/pid.c | 4 ++--
5 files changed, 14 insertions(+), 7 deletions(-)
Index: lx26-21-mm2/include/linux/pid_namespace.h
===================================================================
--- lx26-21-mm2.orig/include/linux/pid_namespace.h 2007-05-22
16:59:29.000000000 -0700
+++ lx26-21-mm2/include/linux/pid_namespace.h 2007-05-22 17:49:52.000000000
-0700
@@ -37,9 +37,14 @@ static inline void put_pid_ns(struct pid
kref_put(&ns->kref, free_pid_ns);
}
+static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
+{
+ return tsk->nsproxy->pid_ns;
+}
+
static inline struct task_struct *child_reaper(struct task_struct *tsk)
{
- return init_pid_ns.child_reaper;
+ return task_active_pid_ns(tsk)->child_reaper;
}
#endif /* _LINUX_PID_NS_H */
Index: lx26-21-mm2/fs/exec.c
===================================================================
--- lx26-21-mm2.orig/fs/exec.c 2007-05-22 16:59:29.000000000 -0700
+++ lx26-21-mm2/fs/exec.c 2007-05-22 17:49:52.000000000 -0700
@@ -629,7 +629,7 @@ static int de_thread(struct task_struct
* so it is safe to do it under read_lock.
*/
if (unlikely(tsk->group_leader == child_reaper(tsk)))
- tsk->nsproxy->pid_ns->child_reaper = tsk;
+ task_active_pid_ns(tsk)->child_reaper = tsk;
zap_other_threads(tsk);
read_unlock(&tasklist_lock);
Index: lx26-21-mm2/fs/proc/proc_misc.c
===================================================================
--- lx26-21-mm2.orig/fs/proc/proc_misc.c 2007-05-22 16:59:29.000000000
-0700
+++ lx26-21-mm2/fs/proc/proc_misc.c 2007-05-22 16:59:34.000000000 -0700
@@ -94,7 +94,8 @@ static int loadavg_read_proc(char *page,
LOAD_INT(a), LOAD_FRAC(a),
LOAD_INT(b), LOAD_FRAC(b),
LOAD_INT(c), LOAD_FRAC(c),
- nr_running(), nr_threads, current->nsproxy->pid_ns->last_pid);
+ nr_running(), nr_threads,
+ task_active_pid_ns(current)->last_pid);
return proc_calc_metrics(page, start, off, count, eof, len);
}
Index: lx26-21-mm2/kernel/exit.c
===================================================================
--- lx26-21-mm2.orig/kernel/exit.c 2007-05-22 16:59:29.000000000 -0700
+++ lx26-21-mm2/kernel/exit.c 2007-05-22 17:49:52.000000000 -0700
@@ -876,8 +876,9 @@ fastcall NORET_TYPE void do_exit(long co
if (unlikely(!tsk->pid))
panic("Attempted to kill the idle task!");
if (unlikely(tsk == child_reaper(tsk))) {
- if (tsk->nsproxy->pid_ns != &init_pid_ns)
- tsk->nsproxy->pid_ns->child_reaper =
init_pid_ns.child_reaper;
+ if (task_active_pid_ns(tsk) != &init_pid_ns)
+ task_active_pid_ns(tsk)->child_reaper =
+ init_pid_ns.child_reaper;
else
panic("Attempted to kill init!");
}
Index: lx26-21-mm2/kernel/pid.c
===================================================================
--- lx26-21-mm2.orig/kernel/pid.c 2007-05-22 16:59:29.000000000 -0700
+++ lx26-21-mm2/kernel/pid.c 2007-05-22 17:49:52.000000000 -0700
@@ -213,7 +213,7 @@ struct pid *alloc_pid(void)
if (!pid)
goto out;
- nr = alloc_pidmap(current->nsproxy->pid_ns);
+ nr = alloc_pidmap(task_active_pid_ns(current));
if (nr < 0)
goto out_free;
@@ -358,7 +358,7 @@ struct pid *find_ge_pid(int nr)
pid = find_pid(nr);
if (pid)
break;
- nr = next_pidmap(current->nsproxy->pid_ns, nr);
+ nr = next_pidmap(task_active_pid_ns(current), nr);
} while (nr > 0);
return pid;
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