tty: The big operations rework

- Operations are now a shared const function block as with most other Linux
  objects

- Introduce wrappers for some optional functions to get consistent behaviour

- Wrap put_char which used to be patched by the tty layer

- Document which functions are needed/optional

- Make put_char report success/fail

- Cache the driver->ops pointer in the tty as tty->ops

- Remove various surplus lock calls we no longer need

- Remove proc_write method as noted by Alexey Dobriyan

- Introduce some missing sanity checks where certain driver/ldisc
  combinations would oops as they didn't check needed methods were present

[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 27 insertions, 68 deletions

diff --git a/drivers/net/irda/irtty-sir.c b/drivers/net/irda/irtty-sir.c
index fc753d7f674e..e6f40b7f9041 100644
--- a/drivers/net/irda/irtty-sir.c
+++ b/drivers/net/irda/irtty-sir.c
@@ -64,7 +64,7 @@ static int irtty_chars_in_buffer(struct sir_dev *dev)
         IRDA_ASSERT(priv != NULL, return -1;);
         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
 
-        return priv->tty->driver->chars_in_buffer(priv->tty);
+        return tty_chars_in_buffer(priv->tty);
 }
 
 /* Wait (sleep) until underlaying hardware finished transmission
@@ -93,10 +93,8 @@ static void irtty_wait_until_sent(struct sir_dev *dev)
         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
 
         tty = priv->tty;
-        if (tty->driver->wait_until_sent) {
-                lock_kernel();
-                tty->driver->wait_until_sent(tty, msecs_to_jiffies(100));
-                unlock_kernel();
+        if (tty->ops->wait_until_sent) {
+                tty->ops->wait_until_sent(tty, msecs_to_jiffies(100));
         }
         else {
                 msleep(USBSERIAL_TX_DONE_DELAY);
@@ -125,48 +123,14 @@ static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
 
         tty = priv->tty;
 
-        lock_kernel();
+        mutex_lock(&tty->termios_mutex);
         old_termios = *(tty->termios);
         cflag = tty->termios->c_cflag;
-
-        cflag &= ~CBAUD;
-
-        IRDA_DEBUG(2, "%s(), Setting speed to %d\n", __FUNCTION__, speed);
-
-        switch (speed) {
-        case 1200:
-                cflag |= B1200;
-                break;
-        case 2400:
-                cflag |= B2400;
-                break;
-        case 4800:
-                cflag |= B4800;
-                break;
-        case 19200:
-                cflag |= B19200;
-                break;
-        case 38400:
-                cflag |= B38400;
-                break;
-        case 57600:
-                cflag |= B57600;
-                break;
-        case 115200:
-                cflag |= B115200;
-                break;
-        case 9600:
-        default:
-                cflag |= B9600;
-                break;
-        }       
-
-        tty->termios->c_cflag = cflag;
-        if (tty->driver->set_termios)
-                tty->driver->set_termios(tty, &old_termios);
-        unlock_kernel();
-
+        tty_encode_baud_rate(tty, speed, speed);
+        if (tty->ops->set_termios)
+                tty->ops->set_termios(tty, &old_termios);
         priv->io.speed = speed;
+        mutex_unlock(&tty->termios_mutex);
 
         return 0;
 }
@@ -202,8 +166,8 @@ static int irtty_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
          * This function is not yet defined for all tty driver, so
          * let's be careful... Jean II
          */
-        IRDA_ASSERT(priv->tty->driver->tiocmset != NULL, return -1;);
-        priv->tty->driver->tiocmset(priv->tty, NULL, set, clear);
+        IRDA_ASSERT(priv->tty->ops->tiocmset != NULL, return -1;);
+        priv->tty->ops->tiocmset(priv->tty, NULL, set, clear);
 
         return 0;
 }
@@ -225,17 +189,13 @@ static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t
         IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
 
         tty = priv->tty;
-        if (!tty->driver->write)
+        if (!tty->ops->write)
                 return 0;
         tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
-        if (tty->driver->write_room) {
-                writelen = tty->driver->write_room(tty);
-                if (writelen > len)
-                        writelen = len;
-        }
-        else
+        writelen = tty_write_room(tty);
+        if (writelen > len)
                 writelen = len;
-        return tty->driver->write(tty, ptr, writelen);
+        return tty->ops->write(tty, ptr, writelen);
 }
 
 /* ------------------------------------------------------- */
@@ -321,7 +281,7 @@ static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
         struct ktermios old_termios;
         int cflag;
 
-        lock_kernel();
+        mutex_lock(&tty->termios_mutex);
         old_termios = *(tty->termios);
         cflag = tty->termios->c_cflag;
         
@@ -331,9 +291,9 @@ static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
                 cflag |= CREAD;
 
         tty->termios->c_cflag = cflag;
-        if (tty->driver->set_termios)
-                tty->driver->set_termios(tty, &old_termios);
-        unlock_kernel();
+        if (tty->ops->set_termios)
+                tty->ops->set_termios(tty, &old_termios);
+        mutex_unlock(&tty->termios_mutex);
 }
 
 /*****************************************************************/
@@ -359,8 +319,8 @@ static int irtty_start_dev(struct sir_dev *dev)
 
         tty = priv->tty;
 
-        if (tty->driver->start)
-                tty->driver->start(tty);
+        if (tty->ops->start)
+                tty->ops->start(tty);
         /* Make sure we can receive more data */
         irtty_stop_receiver(tty, FALSE);
 
@@ -388,8 +348,8 @@ static int irtty_stop_dev(struct sir_dev *dev)
 
         /* Make sure we don't receive more data */
         irtty_stop_receiver(tty, TRUE);
-        if (tty->driver->stop)
-                tty->driver->stop(tty);
+        if (tty->ops->stop)
+                tty->ops->stop(tty);
 
         mutex_unlock(&irtty_mutex);
 
@@ -483,11 +443,10 @@ static int irtty_open(struct tty_struct *tty)
 
         /* stop the underlying  driver */
         irtty_stop_receiver(tty, TRUE);
-        if (tty->driver->stop)
-                tty->driver->stop(tty);
+        if (tty->ops->stop)
+                tty->ops->stop(tty);
 
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        tty_driver_flush_buffer(tty);
         
         /* apply mtt override */
         sir_tty_drv.qos_mtt_bits = qos_mtt_bits;
@@ -564,8 +523,8 @@ static void irtty_close(struct tty_struct *tty)
         /* Stop tty */
         irtty_stop_receiver(tty, TRUE);
         tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
-        if (tty->driver->stop)
-                tty->driver->stop(tty);
+        if (tty->ops->stop)
+                tty->ops->stop(tty);
 
         kfree(priv);