[PATCH] tty: update the tty layer to work with struct pid

Of kernel subsystems that work with pids the tty layer is probably the largest
consumer.  But it has the nice virtue that the assiation with a session only
lasts until the session leader exits.  Which means that no reference counting
is required.  So using struct pid winds up being a simple optimization to
avoid hash table lookups.

In the long term the use of pid_nr also ensures that when we have multiple pid
spaces mixed everything will work correctly.

Signed-off-by: Eric W. Biederman <eric@maxwell.lnxi.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>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c
index c035c2f1f462..6ac3ca4c723c 100644
--- a/drivers/char/n_tty.c
+++ b/drivers/char/n_tty.c
@@ -579,8 +579,8 @@ static void eraser(unsigned char c, struct tty_struct *tty)
  
 static inline void isig(int sig, struct tty_struct *tty, int flush)
 {
-        if (tty->pgrp > 0)
-                kill_pg(tty->pgrp, sig, 1);
+        if (tty->pgrp)
+                kill_pgrp(tty->pgrp, sig, 1);
         if (flush || !L_NOFLSH(tty)) {
                 n_tty_flush_buffer(tty);
                 if (tty->driver->flush_buffer)
@@ -1184,13 +1184,13 @@ static int job_control(struct tty_struct *tty, struct file *file)
         /* don't stop on /dev/console */
         if (file->f_op->write != redirected_tty_write &&
             current->signal->tty == tty) {
-                if (tty->pgrp <= 0)
-                        printk("read_chan: tty->pgrp <= 0!\n");
-                else if (process_group(current) != tty->pgrp) {
+                if (!tty->pgrp)
+                        printk("read_chan: no tty->pgrp!\n");
+                else if (task_pgrp(current) != tty->pgrp) {
                         if (is_ignored(SIGTTIN) ||
                             is_current_pgrp_orphaned())
                                 return -EIO;
-                        kill_pg(process_group(current), SIGTTIN, 1);
+                        kill_pgrp(task_pgrp(current), SIGTTIN, 1);
                         return -ERESTARTSYS;
                 }
         }