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.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 32cb4e6..ccdd506 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -1095,7 +1095,7 @@
LOAD_INT(c), LOAD_FRAC(c),
count_active_contexts(),
atomic_read(&nr_spu_contexts),
- current->nsproxy->pid_ns->last_pid);
+ task_active_pid_ns(current)->last_pid);
return 0;
}
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index c70e047..9c83ba5 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -124,7 +124,7 @@
#if 0
void mconsole_proc(struct mc_request *req)
{
- struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
+ struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
struct file *file;
int n;
char *ptr = req->request.data, *buf;
diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c
index 85c098a..1ed652d 100644
--- a/fs/hppfs/hppfs.c
+++ b/fs/hppfs/hppfs.c
@@ -713,7 +713,7 @@
struct vfsmount *proc_mnt;
int err = -ENOENT;
- proc_mnt = mntget(current->nsproxy->pid_ns->proc_mnt);
+ proc_mnt = mntget(task_active_pid_ns(current)->proc_mnt);
if (IS_ERR(proc_mnt))
goto out;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index cf4c922..163d6fc 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -46,7 +46,7 @@
if (flags & MS_KERNMOUNT)
ns = (struct pid_namespace *)data;
else
- ns = current->nsproxy->pid_ns;
+ ns = task_active_pid_ns(current);
sb = sget(fs_type, proc_test_super, proc_set_super, ns);
if (IS_ERR(sb))
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2731d11..7138ad9 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3099,7 +3099,7 @@
{
struct cgroup_pidlist *l;
/* don't need task_nsproxy() if we're looking at ourself */
- struct pid_namespace *ns = current->nsproxy->pid_ns;
+ struct pid_namespace *ns = task_active_pid_ns(current);
/*
* We can't drop the pidlist_mutex before taking the l->mutex in case
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9efe710..ef69024 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6192,7 +6192,7 @@
event->parent = parent_event;
- event->ns = get_pid_ns(current->nsproxy->pid_ns);
+ event->ns = get_pid_ns(task_active_pid_ns(current));
event->id = atomic64_inc_return(&perf_event_id);
event->state = PERF_EVENT_STATE_INACTIVE;
diff --git a/kernel/pid.c b/kernel/pid.c
index 29d34a1..5641aca 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -343,7 +343,7 @@
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);
@@ -426,7 +426,7 @@
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)
@@ -480,7 +480,7 @@
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);
@@ -491,7 +491,7 @@
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;
diff --git a/kernel/signal.c b/kernel/signal.c
index 415d85d..fd8fcdc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1535,16 +1535,15 @@
* we are under tasklist_lock here so our parent is tied to
* us and cannot exit and release its namespace.
*
- * the only it can is to switch its nsproxy with sys_unshare,
- * bu uncharing pid namespaces is not allowed, so we'll always
- * see relevant namespace
+ * The only it can is to switch its nsproxy with sys_unshare,
+ * but we use the pid_namespace for task_pid which never changes.
*
* write_lock() currently calls preempt_disable() which is the
* same as rcu_read_lock(), but according to Oleg, this is not
* correct to rely on this
*/
rcu_read_lock();
- info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(tsk->parent));
info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();
@@ -1629,7 +1628,7 @@
* see comment in do_notify_parent() about the following 4 lines
*/
rcu_read_lock();
- info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
+ info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
info.si_uid = __task_cred(tsk)->uid;
rcu_read_unlock();
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 3b8e028..20dfc21 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1344,7 +1344,7 @@
goto out_putname;
}
- mnt = current->nsproxy->pid_ns->proc_mnt;
+ mnt = task_active_pid_ns(current)->proc_mnt;
file = file_open_root(mnt->mnt_root, mnt, pathname, flags);
result = PTR_ERR(file);
if (IS_ERR(file))
