tty: Simplify tty_release() state checks

The local o_tty variable in tty_release() is now accessed only
when closing the pty master.

Set o_tty to slave pty when closing pty master, otherwise NULL;
use o_tty != NULL as replacement for pty_master.

Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index e927650a98fd46faed27788a405634d0695104a3..bd7cde3c56efa30557c623bd926c2b6b757a4d5d 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1759,8 +1759,8 @@ static int tty_release_checks(struct tty_struct *tty, int idx)
 int tty_release(struct inode *inode, struct file *filp)
 {
        struct tty_struct *tty = file_tty(filp);
-       struct tty_struct *o_tty;
-       int     pty_master, do_sleep, final;
+       struct tty_struct *o_tty = NULL;
+       int     do_sleep, final;
        int     idx;
        char    buf[64];
 
@@ -1773,10 +1773,9 @@ int tty_release(struct inode *inode, struct file *filp)
        __tty_fasync(-1, filp, 0);
 
        idx = tty->index;
-       pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
-                     tty->driver->subtype == PTY_TYPE_MASTER);
-       /* Review: parallel close */
-       o_tty = tty->link;
+       if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
+           tty->driver->subtype == PTY_TYPE_MASTER)
+               o_tty = tty->link;
 
        if (tty_release_checks(tty, idx)) {
                tty_unlock(tty);
@@ -1820,7 +1819,7 @@ int tty_release(struct inode *inode, struct file *filp)
                                do_sleep++;
                        }
                }
-               if (pty_master && o_tty->count <= 1) {
+               if (o_tty && o_tty->count <= 1) {
                        if (waitqueue_active(&o_tty->read_wait)) {
                                wake_up_poll(&o_tty->read_wait, POLLIN);
                                do_sleep++;
@@ -1838,7 +1837,7 @@ int tty_release(struct inode *inode, struct file *filp)
                schedule();
        }
 
-       if (pty_master) {
+       if (o_tty) {
                if (--o_tty->count < 0) {
                        printk(KERN_WARNING "%s: bad pty slave count (%d) for %s\n",
                                __func__, o_tty->count, tty_name(o_tty, buf));
@@ -1872,13 +1871,13 @@ int tty_release(struct inode *inode, struct file *filp)
        if (!tty->count) {
                read_lock(&tasklist_lock);
                session_clear_tty(tty->session);
-               if (pty_master)
+               if (o_tty)
                        session_clear_tty(o_tty->session);
                read_unlock(&tasklist_lock);
        }
 
        /* check whether both sides are closing ... */
-       final = !tty->count && !(pty_master && o_tty->count);
+       final = !tty->count && !(o_tty && o_tty->count);
 
        tty_unlock_pair(tty, o_tty);
        /* At this point, the tty->count == 0 should ensure a dead tty