46 struct pid init_struct_pid = {
103 void put_pid(struct pid *pid)  in put_pid()  argument
107 	if (!pid)  in put_pid()
110 	ns = pid->numbers[pid->level].ns;  in put_pid()
111 	if (refcount_dec_and_test(&pid->count)) {  in put_pid()
112 		kmem_cache_free(ns->pid_cachep, pid);  in put_pid()
120 	struct pid *pid = container_of(rhp, struct pid, rcu);  in delayed_put_pid()  local
121 	put_pid(pid);  in delayed_put_pid()
124 void free_pid(struct pid *pid)  in free_pid()  argument
131 	for (i = 0; i <= pid->level; i++) {  in free_pid()
132 		struct upid *upid = pid->numbers + i;  in free_pid()
157 	call_rcu(&pid->rcu, delayed_put_pid);  in free_pid()
160 struct pid *alloc_pid(struct pid_namespace *ns)  in alloc_pid()
162 	struct pid *pid;  in alloc_pid()  local
169 	pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);  in alloc_pid()
170 	if (!pid)  in alloc_pid()
174 	pid->level = ns->level;  in alloc_pid()
203 		pid->numbers[i].nr = nr;  in alloc_pid()
204 		pid->numbers[i].ns = tmp;  in alloc_pid()
208 	if (unlikely(is_child_reaper(pid))) {  in alloc_pid()
214 	refcount_set(&pid->count, 1);  in alloc_pid()
216 		INIT_HLIST_HEAD(&pid->tasks[type]);  in alloc_pid()
218 	init_waitqueue_head(&pid->wait_pidfd);  in alloc_pid()
220 	upid = pid->numbers + ns->level;  in alloc_pid()
224 	for ( ; upid >= pid->numbers; --upid) {  in alloc_pid()
226 		idr_replace(&upid->ns->idr, pid, upid->nr);  in alloc_pid()
231 	return pid;  in alloc_pid()
240 		upid = pid->numbers + i;  in alloc_pid()
250 	kmem_cache_free(ns->pid_cachep, pid);  in alloc_pid()
261 struct pid *find_pid_ns(int nr, struct pid_namespace *ns)  in find_pid_ns()
267 struct pid *find_vpid(int nr)  in find_vpid()
273 static struct pid **task_pid_ptr(struct task_struct *task, enum pid_type type)  in task_pid_ptr()
285 	struct pid *pid = *task_pid_ptr(task, type);  in attach_pid()  local
286 	hlist_add_head_rcu(&task->pid_links[type], &pid->tasks[type]);  in attach_pid()
290 			struct pid *new)  in __change_pid()
292 	struct pid **pid_ptr = task_pid_ptr(task, type);  in __change_pid()
293 	struct pid *pid;  in __change_pid()  local
296 	pid = *pid_ptr;  in __change_pid()
302 		if (!hlist_empty(&pid->tasks[tmp]))  in __change_pid()
305 	free_pid(pid);  in __change_pid()
314 		struct pid *pid)  in change_pid()  argument
316 	__change_pid(task, type, pid);  in change_pid()
329 struct task_struct *pid_task(struct pid *pid, enum pid_type type)  in pid_task()  argument
332 	if (pid) {  in pid_task()
334 		first = rcu_dereference_check(hlist_first_rcu(&pid->tasks[type]),  in pid_task()
371 struct pid *get_task_pid(struct task_struct *task, enum pid_type type)  in get_task_pid()
373 	struct pid *pid;  in get_task_pid()  local
375 	pid = get_pid(rcu_dereference(*task_pid_ptr(task, type)));  in get_task_pid()
377 	return pid;  in get_task_pid()
381 struct task_struct *get_pid_task(struct pid *pid, enum pid_type type)  in get_pid_task()  argument
385 	result = pid_task(pid, type);  in get_pid_task()
393 struct pid *find_get_pid(pid_t nr)  in find_get_pid()
395 	struct pid *pid;  in find_get_pid()  local
398 	pid = get_pid(find_vpid(nr));  in find_get_pid()
401 	return pid;  in find_get_pid()
405 pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)  in pid_nr_ns()  argument
410 	if (pid && ns->level <= pid->level) {  in pid_nr_ns()
411 		upid = &pid->numbers[ns->level];  in pid_nr_ns()
419 pid_t pid_vnr(struct pid *pid)  in pid_vnr()  argument
421 	return pid_nr_ns(pid, task_active_pid_ns(current));  in pid_vnr()
452 struct pid *find_ge_pid(int nr, struct pid_namespace *ns)  in find_ge_pid()
470 static int pidfd_create(struct pid *pid)  in pidfd_create()  argument
474 	fd = anon_inode_getfd("[pidfd]", &pidfd_fops, get_pid(pid),  in pidfd_create()
477 		put_pid(pid);  in pidfd_create()
498 SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int, flags)  in SYSCALL_DEFINE2()  argument
501 	struct pid *p;  in SYSCALL_DEFINE2()
506 	if (pid <= 0)  in SYSCALL_DEFINE2()
509 	p = find_get_pid(pid);  in SYSCALL_DEFINE2()
538 	init_pid_ns.pid_cachep = KMEM_CACHE(pid,  in pid_idr_init()