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Commit b461cc03 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

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: default avatarPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 07543f5c

include/linux/pid_namespace.h

+6 −4
Original line number Diff line number Diff line
@@ -4,7 +4,6 @@ 
#include <linux/sched.h>

#include <linux/mm.h>

#include <linux/threads.h>

#include <linux/pid.h>

#include <linux/nsproxy.h>

#include <linux/kref.h>
@@ -32,6 +31,7 @@ extern struct pid_namespace init_pid_ns; 


static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)

{

	if (ns != &init_pid_ns)

		kref_get(&ns->kref);

	return ns;

}
@@ -41,6 +41,7 @@ extern void free_pid_ns(struct kref *kref); 


static inline void put_pid_ns(struct pid_namespace *ns)

{

	if (ns != &init_pid_ns)

		kref_put(&ns->kref, free_pid_ns);

}
@@ -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 */

include/linux/sched.h

+5 −7
Original line number Diff line number Diff line
@@ -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;

kernel/pid.c

+14 −7
Original line number Diff line number Diff line
@@ -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
@@ -192,7 +202,6 @@ 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);

	}

}
@@ -244,9 +253,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) 
		tmp = tmp->parent;

	}



	if (ns != &init_pid_ns)

	get_pid_ns(ns);



	pid->level = ns->level;

	pid->nr = pid->numbers[0].nr;

	atomic_set(&pid->count, 1);