1 files changed, 29 insertions, 2 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 77e8cad3b17a..511cc4549f58 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1514,8 +1514,35 @@ extern struct task_struct init_task;
 
 extern struct   mm_struct init_mm;
 
-#define find_task_by_pid(nr)    find_task_by_pid_type(PIDTYPE_PID, nr)
-extern struct task_struct *find_task_by_pid_type(int type, int pid);
+extern struct pid_namespace init_pid_ns;
+
+/*
+ * find a task by one of its numerical ids
+ *
+ * find_task_by_pid_type_ns():
+ *      it is the most generic call - it finds a task by all id,
+ *      type and namespace specified
+ * find_task_by_pid_ns():
+ *      finds a task by its pid in the specified namespace
+ * find_task_by_pid_type():
+ *      finds a task by its global id with the specified type, e.g.
+ *      by global session id
+ * find_task_by_pid():
+ *      finds a task by its global pid
+ *
+ * see also find_pid() etc in include/linux/pid.h
+ */
+
+extern struct task_struct *find_task_by_pid_type_ns(int type, int pid,
+                struct pid_namespace *ns);
+
+#define find_task_by_pid_ns(nr, ns)     \
+                find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns)
+#define find_task_by_pid_type(type, nr) \
+                find_task_by_pid_type_ns(type, nr, &init_pid_ns)
+#define find_task_by_pid(nr)            \
+                find_task_by_pid_type(PIDTYPE_PID, nr)
+
 extern void __set_special_pids(pid_t session, pid_t pgrp);
 
 /* per-UID process charging. */