1 files changed, 43 insertions, 34 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 0e6866fe0f96..daeb8f766971 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2496,45 +2496,26 @@ static int tiocgwinsz(struct tty_struct *tty, struct winsize __user *arg)
 }
 
 /**
- *      tiocswinsz              -       implement window size set ioctl
- *      @tty; tty
- *      @arg: user buffer for result
+ *      tty_do_resize           -       resize event
+ *      @tty: tty being resized
+ *      @real_tty: real tty (not the same as tty if using a pty/tty pair)
+ *      @rows: rows (character)
+ *      @cols: cols (character)
  *
- *      Copies the user idea of the window size to the kernel. Traditionally
- *      this is just advisory information but for the Linux console it
- *      actually has driver level meaning and triggers a VC resize.
- *
- *      Locking:
- *              Called function use the console_sem is used to ensure we do
- *      not try and resize the console twice at once.
- *              The tty->termios_mutex is used to ensure we don't double
- *      resize and get confused. Lock order - tty->termios_mutex before
- *      console sem
+ *      Update the termios variables and send the neccessary signals to
+ *      peform a terminal resize correctly
  */
 
-static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
-        struct winsize __user *arg)
+int tty_do_resize(struct tty_struct *tty, struct tty_struct *real_tty,
+                                        struct winsize *ws)
 {
-        struct winsize tmp_ws;
         struct pid *pgrp, *rpgrp;
         unsigned long flags;
 
-        if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
-                return -EFAULT;
-
-        mutex_lock(&tty->termios_mutex);
-        if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg)))
+        /* For a PTY we need to lock the tty side */
+        mutex_lock(&real_tty->termios_mutex);
+        if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
                 goto done;
-
-#ifdef CONFIG_VT
-        if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) {
-                if (vc_lock_resize(tty->driver_data, tmp_ws.ws_col,
-                                        tmp_ws.ws_row)) {
-                        mutex_unlock(&tty->termios_mutex);
-                        return -ENXIO;
-                }
-        }
-#endif
         /* Get the PID values and reference them so we can
            avoid holding the tty ctrl lock while sending signals */
         spin_lock_irqsave(&tty->ctrl_lock, flags);
@@ -2550,14 +2531,42 @@ static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
         put_pid(pgrp);
         put_pid(rpgrp);
 
-        tty->winsize = tmp_ws;
-        real_tty->winsize = tmp_ws;
+        tty->winsize = *ws;
+        real_tty->winsize = *ws;
 done:
-        mutex_unlock(&tty->termios_mutex);
+        mutex_unlock(&real_tty->termios_mutex);
         return 0;
 }
 
 /**
+ *      tiocswinsz              -       implement window size set ioctl
+ *      @tty; tty
+ *      @arg: user buffer for result
+ *
+ *      Copies the user idea of the window size to the kernel. Traditionally
+ *      this is just advisory information but for the Linux console it
+ *      actually has driver level meaning and triggers a VC resize.
+ *
+ *      Locking:
+ *              Driver dependant. The default do_resize method takes the
+ *      tty termios mutex and ctrl_lock. The console takes its own lock
+ *      then calls into the default method.
+ */
+
+static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty,
+        struct winsize __user *arg)
+{
+        struct winsize tmp_ws;
+        if (copy_from_user(&tmp_ws, arg, sizeof(*arg)))
+                return -EFAULT;
+
+        if (tty->ops->resize)
+                return tty->ops->resize(tty, real_tty, &tmp_ws);
+        else
+                return tty_do_resize(tty, real_tty, &tmp_ws);
+}
+
+/**
  *      tioccons        -       allow admin to move logical console
  *      @file: the file to become console
  *