[PATCH] tty: make __proc_set_tty static

The aim of this patch set is to start wrapping up the struct pid conversions.
As such this patchset culminates with the removal of kill_pg, kill_pg_info,
__kill_pg_info, do_each_task_pid, and while_each_task_pid.

kill_proc, daemonize, and kernel_thread are still in my sights but there is
still work to get to them.

The first three are basic cleanups around disassociate_ctty, while working on
converting it I found several issues.  tty_old_pgrp can be a tricky concept to
wrap your head around.

 1 tty: Make __proc_set_tty static.
 2 tty: Clarify disassociate_ctty
 3 tty: Fix the locking for signal->session in disassociate_ctty

These just stop using the old helper functions.

 4 signal: Use kill_pgrp not kill_pg in the sunos compatibility code.
 5 signal: Rewrite kill_something_info so it uses newer helpers.

Then the grind to convert the tty layer and all of it's helper functions to
struct pid.

 6 pid: Make session_of_pgrp use struct pid instead of pid_t.
 7 pid: Use struct pid for talking about process groups in exit.c
 8 pid: Replace is_orphaned_pgrp with is_current_pgrp_orphaned
 9 tty: Update the tty layer to work with struct pid.

A final helper function update.

10 pid: Replace do/while_each_task_pid with do/while_each_pid_task

And the removal of the functions that are now unused.
11 pid: Remove now unused do_each_task_pid and while_each_task_pid
12 pid: Remove the now unused kill_pg kill_pg_info and __kill_pg_info

All of these should be fairly simple and to the point.

This patch:

Currently all users of __proc_set_tty are in tty_io.c so make the function
static.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/tty_io.c

@@ -155,6 +155,7 @@ int tty_ioctl(struct inode * inode, struct file * file,
 	      unsigned int cmd, unsigned long arg);
 static int tty_fasync(int fd, struct file * filp, int on);
 static void release_tty(struct tty_struct *tty, int idx);
+static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
 
 /**
  *	alloc_tty_struct	-	allocate a tty object
@@ -3791,7 +3792,7 @@ void proc_clear_tty(struct task_struct *p)
 }
 EXPORT_SYMBOL(proc_clear_tty);
 
-void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
+static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
 {
 	if (tty) {
 		tty->session = process_session(tsk);

include/linux/tty.h

@@ -333,7 +333,6 @@ extern int tty_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 
 extern dev_t tty_devnum(struct tty_struct *tty);
 extern void proc_clear_tty(struct task_struct *p);
-extern void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
 extern void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
 extern struct tty_struct *get_current_tty(void);