From b461cc03828c743aed6b3855b9ab0d39a9d54ec5 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 18 Oct 2007 23:40:09 -0700 Subject: [PATCH] pid namespaces: miscellaneous preparations for pid namespaces * remove pid.h from pid_namespaces.h; * rework is_(cgroup|global)_init; * optimize (get|put)_pid_ns for init_pid_ns; * declare task_child_reaper to return actual reaper. Signed-off-by: Pavel Emelyanov Cc: Oleg Nesterov Cc: Sukadev Bhattiprolu Cc: Paul Menage Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pid_namespace.h | 10 ++++++---- include/linux/sched.h | 12 +++++------- kernel/pid.c | 21 ++++++++++++++------- 3 files changed, 25 insertions(+), 18 deletions(-) diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index 416d4e4ce94..0135c76c76c 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -4,7 +4,6 @@ #include #include #include -#include #include #include @@ -32,7 +31,8 @@ extern struct pid_namespace init_pid_ns; static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) { - kref_get(&ns->kref); + if (ns != &init_pid_ns) + kref_get(&ns->kref); return ns; } @@ -41,7 +41,8 @@ extern void free_pid_ns(struct kref *kref); static inline void put_pid_ns(struct pid_namespace *ns) { - kref_put(&ns->kref, free_pid_ns); + if (ns != &init_pid_ns) + kref_put(&ns->kref, free_pid_ns); } static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk) @@ -51,7 +52,8 @@ static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk) static inline struct task_struct *task_child_reaper(struct task_struct *tsk) { - return init_pid_ns.child_reaper; + BUG_ON(tsk != current); + return tsk->nsproxy->pid_ns->child_reaper; } #endif /* _LINUX_PID_NS_H */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 511cc4549f5..b0bf326143a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1329,19 +1329,17 @@ static inline int pid_alive(struct task_struct *p) * @tsk: Task structure to be checked. * * Check if a task structure is the first user space task the kernel created. - * - * TODO: We should inline this function after some cleanups in pid_namespace.h */ -extern int is_global_init(struct task_struct *tsk); +static inline int is_global_init(struct task_struct *tsk) +{ + return tsk->pid == 1; +} /* * is_container_init: * check whether in the task is init in its own pid namespace. */ -static inline int is_container_init(struct task_struct *tsk) -{ - return tsk->pid == 1; -} +extern int is_container_init(struct task_struct *tsk); extern struct pid *cad_pid; diff --git a/kernel/pid.c b/kernel/pid.c index a2b4cbbdd63..4b17acdb862 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -73,10 +73,20 @@ struct pid_namespace init_pid_ns = { }; EXPORT_SYMBOL_GPL(init_pid_ns); -int is_global_init(struct task_struct *tsk) +int is_container_init(struct task_struct *tsk) { - return tsk == init_pid_ns.child_reaper; + int ret = 0; + struct pid *pid; + + rcu_read_lock(); + pid = task_pid(tsk); + if (pid != NULL && pid->numbers[pid->level].nr == 1) + ret = 1; + rcu_read_unlock(); + + return ret; } +EXPORT_SYMBOL(is_container_init); /* * Note: disable interrupts while the pidmap_lock is held as an @@ -192,8 +202,7 @@ fastcall void put_pid(struct pid *pid) if ((atomic_read(&pid->count) == 1) || atomic_dec_and_test(&pid->count)) { kmem_cache_free(ns->pid_cachep, pid); - if (ns != &init_pid_ns) - put_pid_ns(ns); + put_pid_ns(ns); } } EXPORT_SYMBOL_GPL(put_pid); @@ -244,9 +253,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) tmp = tmp->parent; } - if (ns != &init_pid_ns) - get_pid_ns(ns); - + get_pid_ns(ns); pid->level = ns->level; pid->nr = pid->numbers[0].nr; atomic_set(&pid->count, 1); -- 2.20.1