Commit 74bd59bb authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

namespaces: cleanup the code managed with PID_NS option 



Just like with the user namespaces, move the namespace management code into
the separate .c file and mark the (already existing) PID_NS option as "depend
on NAMESPACES"

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aee16ce7

include/linux/pid.h

+1 −1
Original line number Diff line number Diff line
@@ -118,10 +118,10 @@ extern struct pid *find_pid(int nr); 
 */

extern struct pid *find_get_pid(int nr);

extern struct pid *find_ge_pid(int nr, struct pid_namespace *);

int next_pidmap(struct pid_namespace *pid_ns, int last);



extern struct pid *alloc_pid(struct pid_namespace *ns);

extern void FASTCALL(free_pid(struct pid *pid));

extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);



/*

 * the helpers to get the pid's id seen from different namespaces

include/linux/pid_namespace.h

+6 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) 


extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *ns);

extern void free_pid_ns(struct kref *kref);

extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);



static inline void put_pid_ns(struct pid_namespace *ns)

{
@@ -66,6 +67,11 @@ static inline void put_pid_ns(struct pid_namespace *ns) 
{

}





static inline void zap_pid_ns_processes(struct pid_namespace *ns)

{

	BUG();

}

#endif /* CONFIG_PID_NS */



static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)

init/Kconfig

+12 −12
Original line number Diff line number Diff line
@@ -214,18 +214,6 @@ config TASK_IO_ACCOUNTING 


	  Say N if unsure.



config PID_NS

	bool "PID Namespaces (EXPERIMENTAL)"

	default n

	depends on EXPERIMENTAL

	help

	  Suport process id namespaces.  This allows having multiple

	  process with the same pid as long as they are in different

	  pid namespaces.  This is a building block of containers.



	  Unless you want to work with an experimental feature

	  say N here.



config AUDIT

	bool "Auditing support"

	depends on NET
@@ -442,6 +430,18 @@ config USER_NS 
	  to provide different user info for different servers.

	  If unsure, say N.



config PID_NS

	bool "PID Namespaces (EXPERIMENTAL)"

	default n

	depends on NAMESPACES && EXPERIMENTAL

	help

	  Suport process id namespaces.  This allows having multiple

	  process with the same pid as long as they are in different

	  pid namespaces.  This is a building block of containers.



	  Unless you want to work with an experimental feature

	  say N here.



config BLK_DEV_INITRD

	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"

	depends on BROKEN || !FRV

kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ obj-$(CONFIG_CPUSETS) += cpuset.o 
obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o

obj-$(CONFIG_UTS_NS) += utsname.o

obj-$(CONFIG_USER_NS) += user_namespace.o

obj-$(CONFIG_PID_NS) += pid_namespace.o

obj-$(CONFIG_IKCONFIG) += configs.o

obj-$(CONFIG_RESOURCE_COUNTERS) += res_counter.o

obj-$(CONFIG_STOP_MACHINE) += stop_machine.o

kernel/pid.c

+3 −181
Original line number Diff line number Diff line
@@ -41,7 +41,6 @@ 
static struct hlist_head *pid_hash;

static int pidhash_shift;

struct pid init_struct_pid = INIT_STRUCT_PID;

static struct kmem_cache *pid_ns_cachep;



int pid_max = PID_MAX_DEFAULT;
@@ -181,7 +180,7 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) 
	return -1;

}



static int next_pidmap(struct pid_namespace *pid_ns, int last)

int next_pidmap(struct pid_namespace *pid_ns, int last)

{

	int offset;

	struct pidmap *map, *end;
@@ -488,180 +487,6 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns) 
}

EXPORT_SYMBOL_GPL(find_get_pid);



struct pid_cache {

	int nr_ids;

	char name[16];

	struct kmem_cache *cachep;

	struct list_head list;

};



static LIST_HEAD(pid_caches_lh);

static DEFINE_MUTEX(pid_caches_mutex);



/*

 * creates the kmem cache to allocate pids from.

 * @nr_ids: the number of numerical ids this pid will have to carry

 */



static struct kmem_cache *create_pid_cachep(int nr_ids)

{

	struct pid_cache *pcache;

	struct kmem_cache *cachep;



	mutex_lock(&pid_caches_mutex);

	list_for_each_entry (pcache, &pid_caches_lh, list)

		if (pcache->nr_ids == nr_ids)

			goto out;



	pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL);

	if (pcache == NULL)

		goto err_alloc;



	snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids);

	cachep = kmem_cache_create(pcache->name,

			sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid),

			0, SLAB_HWCACHE_ALIGN, NULL);

	if (cachep == NULL)

		goto err_cachep;



	pcache->nr_ids = nr_ids;

	pcache->cachep = cachep;

	list_add(&pcache->list, &pid_caches_lh);

out:

	mutex_unlock(&pid_caches_mutex);

	return pcache->cachep;



err_cachep:

	kfree(pcache);

err_alloc:

	mutex_unlock(&pid_caches_mutex);

	return NULL;

}



#ifdef CONFIG_PID_NS

static struct pid_namespace *create_pid_namespace(int level)

{

	struct pid_namespace *ns;

	int i;



	ns = kmem_cache_alloc(pid_ns_cachep, GFP_KERNEL);

	if (ns == NULL)

		goto out;



	ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);

	if (!ns->pidmap[0].page)

		goto out_free;



	ns->pid_cachep = create_pid_cachep(level + 1);

	if (ns->pid_cachep == NULL)

		goto out_free_map;



	kref_init(&ns->kref);

	ns->last_pid = 0;

	ns->child_reaper = NULL;

	ns->level = level;



	set_bit(0, ns->pidmap[0].page);

	atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);



	for (i = 1; i < PIDMAP_ENTRIES; i++) {

		ns->pidmap[i].page = 0;

		atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);

	}



	return ns;



out_free_map:

	kfree(ns->pidmap[0].page);

out_free:

	kmem_cache_free(pid_ns_cachep, ns);

out:

	return ERR_PTR(-ENOMEM);

}



static void destroy_pid_namespace(struct pid_namespace *ns)

{

	int i;



	for (i = 0; i < PIDMAP_ENTRIES; i++)

		kfree(ns->pidmap[i].page);

	kmem_cache_free(pid_ns_cachep, ns);

}



struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)

{

	struct pid_namespace *new_ns;



	BUG_ON(!old_ns);

	new_ns = get_pid_ns(old_ns);

	if (!(flags & CLONE_NEWPID))

		goto out;



	new_ns = ERR_PTR(-EINVAL);

	if (flags & CLONE_THREAD)

		goto out_put;



	new_ns = create_pid_namespace(old_ns->level + 1);

	if (!IS_ERR(new_ns))

		new_ns->parent = get_pid_ns(old_ns);



out_put:

	put_pid_ns(old_ns);

out:

	return new_ns;

}



void free_pid_ns(struct kref *kref)

{

	struct pid_namespace *ns, *parent;



	ns = container_of(kref, struct pid_namespace, kref);



	parent = ns->parent;

	destroy_pid_namespace(ns);



	if (parent != NULL)

		put_pid_ns(parent);

}

#endif /* CONFIG_PID_NS */



void zap_pid_ns_processes(struct pid_namespace *pid_ns)

{

	int nr;

	int rc;



	/*

	 * The last thread in the cgroup-init thread group is terminating.

	 * Find remaining pid_ts in the namespace, signal and wait for them

	 * to exit.

	 *

	 * Note:  This signals each threads in the namespace - even those that

	 * 	  belong to the same thread group, To avoid this, we would have

	 * 	  to walk the entire tasklist looking a processes in this

	 * 	  namespace, but that could be unnecessarily expensive if the

	 * 	  pid namespace has just a few processes. Or we need to

	 * 	  maintain a tasklist for each pid namespace.

	 *

	 */

	read_lock(&tasklist_lock);

	nr = next_pidmap(pid_ns, 1);

	while (nr > 0) {

		kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);

		nr = next_pidmap(pid_ns, nr);

	}

	read_unlock(&tasklist_lock);



	do {

		clear_thread_flag(TIF_SIGPENDING);

		rc = sys_wait4(-1, NULL, __WALL, NULL);

	} while (rc != -ECHILD);





	/* Child reaper for the pid namespace is going away */

	pid_ns->child_reaper = NULL;

	return;

}



/*

 * The pid hash table is scaled according to the amount of memory in the

 * machine.  From a minimum of 16 slots up to 4096 slots at one gigabyte or
@@ -694,9 +519,6 @@ void __init pidmap_init(void) 
	set_bit(0, init_pid_ns.pidmap[0].page);

	atomic_dec(&init_pid_ns.pidmap[0].nr_free);



	init_pid_ns.pid_cachep = create_pid_cachep(1);

	if (init_pid_ns.pid_cachep == NULL)

		panic("Can't create pid_1 cachep\n");



	pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);

	init_pid_ns.pid_cachep = KMEM_CACHE(pid,

			SLAB_HWCACHE_ALIGN | SLAB_PANIC);

}

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