Uninline find_task_by_xxx set of functions

The find_task_by_something is a set of macros are used to find task by pid
depending on what kind of pid is proposed - global or virtual one.  All of
them are wrappers above the most generic one - find_task_by_pid_type_ns() -
and just substitute some args for it.

It turned out, that dereferencing the current->nsproxy->pid_ns construction
and pushing one more argument on the stack inline cause kernel text size to
grow.

This patch moves all this stuff out-of-line into kernel/pid.c.  Together
with the next patch it saves a bit less than 400 bytes from the .text
section.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1301c08..f4d969e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1523,9 +1523,8 @@
  *      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_vpid():
+ *      finds a task by its virtual pid
  * find_task_by_pid():
  *      finds a task by its global pid
  *
@@ -1535,12 +1534,10 @@
 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 struct task_struct *find_task_by_pid(pid_t nr);
+extern struct task_struct *find_task_by_vpid(pid_t nr);
+extern struct task_struct *find_task_by_pid_ns(pid_t nr,
+		struct pid_namespace *ns);
 
 extern void __set_special_pids(pid_t session, pid_t pgrp);