pidns: Use task_active_pid_ns where appropriate
The expressions tsk->nsproxy->pid_ns and task_active_pid_ns
aka ns_of_pid(task_pid(tsk)) should have the same number of
cache line misses with the practical difference that
ns_of_pid(task_pid(tsk)) is released later in a processes life.
Furthermore by using task_active_pid_ns it becomes trivial
to write an unshare implementation for the the pid namespace.
So I have used task_active_pid_ns everywhere I can.
In fork since the pid has not yet been attached to the
process I use ns_of_pid, to achieve the same effect.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/kernel/pid.c b/kernel/pid.c
index 2a624f1..3a5f238 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -345,7 +345,7 @@
struct pid *find_vpid(int nr)
{
- return find_pid_ns(nr, current->nsproxy->pid_ns);
+ return find_pid_ns(nr, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(find_vpid);
@@ -429,7 +429,7 @@
struct task_struct *find_task_by_vpid(pid_t vnr)
{
- return find_task_by_pid_ns(vnr, current->nsproxy->pid_ns);
+ return find_task_by_pid_ns(vnr, task_active_pid_ns(current));
}
struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
@@ -484,7 +484,7 @@
pid_t pid_vnr(struct pid *pid)
{
- return pid_nr_ns(pid, current->nsproxy->pid_ns);
+ return pid_nr_ns(pid, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(pid_vnr);
@@ -495,7 +495,7 @@
rcu_read_lock();
if (!ns)
- ns = current->nsproxy->pid_ns;
+ ns = task_active_pid_ns(current);
if (likely(pid_alive(task))) {
if (type != PIDTYPE_PID)
task = task->group_leader;