tty: fix unused warning when TCGETX is not defined

[pandora-kernel.git] / drivers / char / tty_ioctl.c

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 6f4c7d0..b24f6c6 100644 (file)
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -97,14 +97,19 @@ EXPORT_SYMBOL(tty_driver_flush_buffer);
  *     @tty: terminal
  *
  *     Indicate that a tty should stop transmitting data down the stack.
+ *     Takes the termios mutex to protect against parallel throttle/unthrottle
+ *     and also to ensure the driver can consistently reference its own
+ *     termios data at this point when implementing software flow control.
  */
 
 void tty_throttle(struct tty_struct *tty)
 {
+       mutex_lock(&tty->termios_mutex);
        /* check TTY_THROTTLED first so it indicates our state */
        if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
            tty->ops->throttle)
                tty->ops->throttle(tty);
+       mutex_unlock(&tty->termios_mutex);
 }
 EXPORT_SYMBOL(tty_throttle);
 
@@ -113,13 +118,21 @@ EXPORT_SYMBOL(tty_throttle);
  *     @tty: terminal
  *
  *     Indicate that a tty may continue transmitting data down the stack.
+ *     Takes the termios mutex to protect against parallel throttle/unthrottle
+ *     and also to ensure the driver can consistently reference its own
+ *     termios data at this point when implementing software flow control.
+ *
+ *     Drivers should however remember that the stack can issue a throttle,
+ *     then change flow control method, then unthrottle.
  */
 
 void tty_unthrottle(struct tty_struct *tty)
 {
+       mutex_lock(&tty->termios_mutex);
        if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
            tty->ops->unthrottle)
                tty->ops->unthrottle(tty);
+       mutex_unlock(&tty->termios_mutex);
 }
 EXPORT_SYMBOL(tty_unthrottle);
 
@@ -613,9 +626,25 @@ static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
        return 0;
 }
 
+static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
+{
+       mutex_lock(&tty->termios_mutex);
+       memcpy(kterm, tty->termios, sizeof(struct ktermios));
+       mutex_unlock(&tty->termios_mutex);
+}
+
+static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
+{
+       mutex_lock(&tty->termios_mutex);
+       memcpy(kterm, tty->termios_locked, sizeof(struct ktermios));
+       mutex_unlock(&tty->termios_mutex);
+}
+
 static int get_termio(struct tty_struct *tty, struct termio __user *termio)
 {
-       if (kernel_termios_to_user_termio(termio, tty->termios))
+       struct ktermios kterm;
+       copy_termios(tty, &kterm);
+       if (kernel_termios_to_user_termio(termio, &kterm))
                return -EFAULT;
        return 0;
 }
@@ -917,6 +946,7 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
        struct tty_struct *real_tty;
        void __user *p = (void __user *)arg;
        int ret = 0;
+       struct ktermios kterm;
 
        if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
            tty->driver->subtype == PTY_TYPE_MASTER)
@@ -952,23 +982,20 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
                return set_termios(real_tty, p, TERMIOS_OLD);
 #ifndef TCGETS2
        case TCGETS:
-               mutex_lock(&real_tty->termios_mutex);
-               if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios))
+               copy_termios(real_tty, &kterm);
+               if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
                        ret = -EFAULT;
-               mutex_unlock(&real_tty->termios_mutex);
                return ret;
 #else
        case TCGETS:
-               mutex_lock(&real_tty->termios_mutex);
-               if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios))
+               copy_termios(real_tty, &kterm);
+               if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
                        ret = -EFAULT;
-               mutex_unlock(&real_tty->termios_mutex);
                return ret;
        case TCGETS2:
-               mutex_lock(&real_tty->termios_mutex);
-               if (kernel_termios_to_user_termios((struct termios2 __user *)arg, real_tty->termios))
+               copy_termios(real_tty, &kterm);
+               if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
                        ret = -EFAULT;
-               mutex_unlock(&real_tty->termios_mutex);
                return ret;
        case TCSETSF2:
                return set_termios(real_tty, p,  TERMIOS_FLUSH | TERMIOS_WAIT);
@@ -987,46 +1014,51 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
                return set_termios(real_tty, p, TERMIOS_TERMIO);
 #ifndef TCGETS2
        case TIOCGLCKTRMIOS:
-               mutex_lock(&real_tty->termios_mutex);
-               if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked))
+               copy_termios_locked(real_tty, &kterm);
+               if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
                        ret = -EFAULT;
-               mutex_unlock(&real_tty->termios_mutex);
                return ret;
        case TIOCSLCKTRMIOS:
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
-               mutex_lock(&real_tty->termios_mutex);
-               if (user_termios_to_kernel_termios(real_tty->termios_locked,
+               copy_termios_locked(real_tty, &kterm);
+               if (user_termios_to_kernel_termios(&kterm,
                                               (struct termios __user *) arg))
-                       ret = -EFAULT;
+                       return -EFAULT;
+               mutex_lock(&real_tty->termios_mutex);
+               memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
                mutex_unlock(&real_tty->termios_mutex);
-               return ret;
+               return 0;
 #else
        case TIOCGLCKTRMIOS:
-               mutex_lock(&real_tty->termios_mutex);
-               if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios_locked))
+               copy_termios_locked(real_tty, &kterm);
+               if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
                        ret = -EFAULT;
-               mutex_unlock(&real_tty->termios_mutex);
                return ret;
        case TIOCSLCKTRMIOS:
                if (!capable(CAP_SYS_ADMIN))
-                       ret = -EPERM;
-               mutex_lock(&real_tty->termios_mutex);
-               if (user_termios_to_kernel_termios_1(real_tty->termios_locked,
+                       return -EPERM;
+               copy_termios_locked(real_tty, &kterm);
+               if (user_termios_to_kernel_termios_1(&kterm,
                                               (struct termios __user *) arg))
-                       ret = -EFAULT;
+                       return -EFAULT;
+               mutex_lock(&real_tty->termios_mutex);
+               memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
                mutex_unlock(&real_tty->termios_mutex);
                return ret;
 #endif
 #ifdef TCGETX
-       case TCGETX:
+       case TCGETX: {
+               struct termiox ktermx;
                if (real_tty->termiox == NULL)
                        return -EINVAL;
                mutex_lock(&real_tty->termios_mutex);
-               if (copy_to_user(p, real_tty->termiox, sizeof(struct termiox)))
-                       ret = -EFAULT;
+               memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
                mutex_unlock(&real_tty->termios_mutex);
+               if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
+                       ret = -EFAULT;
                return ret;
+       }
        case TCSETX:
                return set_termiox(real_tty, p, 0);
        case TCSETXW:
@@ -1035,10 +1067,9 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
                return set_termiox(real_tty, p, TERMIOS_FLUSH);
 #endif         
        case TIOCGSOFTCAR:
-               mutex_lock(&real_tty->termios_mutex);
-               ret = put_user(C_CLOCAL(real_tty) ? 1 : 0,
+               copy_termios(real_tty, &kterm);
+               ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
                                                (int __user *)arg);
-               mutex_unlock(&real_tty->termios_mutex);
                return ret;
        case TIOCSSOFTCAR:
                if (get_user(arg, (unsigned int __user *) arg))