v4.19.13 snapshot.
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
new file mode 100644
index 0000000..49538b1
--- /dev/null
+++ b/include/linux/pid_namespace.h
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PID_NS_H
+#define _LINUX_PID_NS_H
+
+#include <linux/sched.h>
+#include <linux/bug.h>
+#include <linux/mm.h>
+#include <linux/workqueue.h>
+#include <linux/threads.h>
+#include <linux/nsproxy.h>
+#include <linux/kref.h>
+#include <linux/ns_common.h>
+#include <linux/idr.h>
+
+
+struct fs_pin;
+
+enum { /* definitions for pid_namespace's hide_pid field */
+ HIDEPID_OFF = 0,
+ HIDEPID_NO_ACCESS = 1,
+ HIDEPID_INVISIBLE = 2,
+};
+
+struct pid_namespace {
+ struct kref kref;
+ struct idr idr;
+ struct rcu_head rcu;
+ unsigned int pid_allocated;
+ struct task_struct *child_reaper;
+ struct kmem_cache *pid_cachep;
+ unsigned int level;
+ struct pid_namespace *parent;
+#ifdef CONFIG_PROC_FS
+ struct vfsmount *proc_mnt;
+ struct dentry *proc_self;
+ struct dentry *proc_thread_self;
+#endif
+#ifdef CONFIG_BSD_PROCESS_ACCT
+ struct fs_pin *bacct;
+#endif
+ struct user_namespace *user_ns;
+ struct ucounts *ucounts;
+ struct work_struct proc_work;
+ kgid_t pid_gid;
+ int hide_pid;
+ int reboot; /* group exit code if this pidns was rebooted */
+ struct ns_common ns;
+} __randomize_layout;
+
+extern struct pid_namespace init_pid_ns;
+
+#define PIDNS_ADDING (1U << 31)
+
+#ifdef CONFIG_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;
+}
+
+extern struct pid_namespace *copy_pid_ns(unsigned long flags,
+ struct user_namespace *user_ns, struct pid_namespace *ns);
+extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
+extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
+extern void put_pid_ns(struct pid_namespace *ns);
+
+#else /* !CONFIG_PID_NS */
+#include <linux/err.h>
+
+static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
+{
+ return ns;
+}
+
+static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
+ struct user_namespace *user_ns, struct pid_namespace *ns)
+{
+ if (flags & CLONE_NEWPID)
+ ns = ERR_PTR(-EINVAL);
+ return ns;
+}
+
+static inline void put_pid_ns(struct pid_namespace *ns)
+{
+}
+
+static inline void zap_pid_ns_processes(struct pid_namespace *ns)
+{
+ BUG();
+}
+
+static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
+{
+ return 0;
+}
+#endif /* CONFIG_PID_NS */
+
+extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
+void pidhash_init(void);
+void pid_idr_init(void);
+
+#endif /* _LINUX_PID_NS_H */