tty_port: handle the nonblocking open of a dead port corner case
[linux-2.6.git] / drivers / char / tty_port.c
index 4e862a7..c63f3d3 100644 (file)
@@ -23,6 +23,7 @@ void tty_port_init(struct tty_port *port)
        memset(port, 0, sizeof(*port));
        init_waitqueue_head(&port->open_wait);
        init_waitqueue_head(&port->close_wait);
+       init_waitqueue_head(&port->delta_msr_wait);
        mutex_init(&port->mutex);
        spin_lock_init(&port->lock);
        port->close_delay = (50 * HZ) / 100;
@@ -96,6 +97,14 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_port_tty_set);
 
+static void tty_port_shutdown(struct tty_port *port)
+{
+       if (port->ops->shutdown &&
+               test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
+                       port->ops->shutdown(port);
+
+}
+
 /**
  *     tty_port_hangup         -       hangup helper
  *     @port: tty port
@@ -116,6 +125,8 @@ void tty_port_hangup(struct tty_port *port)
        port->tty = NULL;
        spin_unlock_irqrestore(&port->lock, flags);
        wake_up_interruptible(&port->open_wait);
+       wake_up_interruptible(&port->delta_msr_wait);
+       tty_port_shutdown(port);
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
@@ -208,8 +219,14 @@ int tty_port_block_til_ready(struct tty_port *port,
 
        /* if non-blocking mode is set we can pass directly to open unless
           the port has just hung up or is in another error state */
-       if ((filp->f_flags & O_NONBLOCK) ||
-                       (tty->flags & (1 << TTY_IO_ERROR))) {
+       if (tty->flags & (1 << TTY_IO_ERROR)) {
+               port->flags |= ASYNC_NORMAL_ACTIVE;
+               return 0;
+       }
+       if (filp->f_flags & O_NONBLOCK) {
+               /* Indicate we are open */
+               if (tty->termios->c_cflag & CBAUD)
+                       tty_port_raise_dtr_rts(port);
                port->flags |= ASYNC_NORMAL_ACTIVE;
                return 0;
        }
@@ -267,7 +284,7 @@ int tty_port_block_til_ready(struct tty_port *port,
        if (retval == 0)
                port->flags |= ASYNC_NORMAL_ACTIVE;
        spin_unlock_irqrestore(&port->lock, flags);
-       return 0;
+       return retval;
        
 }
 EXPORT_SYMBOL(tty_port_block_til_ready);
@@ -296,15 +313,17 @@ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct f
 
        if (port->count) {
                spin_unlock_irqrestore(&port->lock, flags);
+               if (port->ops->drop)
+                       port->ops->drop(port);
                return 0;
        }
-       port->flags |= ASYNC_CLOSING;
+       set_bit(ASYNCB_CLOSING, &port->flags);
        tty->closing = 1;
        spin_unlock_irqrestore(&port->lock, flags);
        /* Don't block on a stalled port, just pull the chain */
        if (tty->flow_stopped)
                tty_driver_flush_buffer(tty);
-       if (port->flags & ASYNC_INITIALIZED &&
+       if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
                        port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, port->closing_wait);
        if (port->drain_delay) {
@@ -318,6 +337,9 @@ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct f
                        timeout = 2 * HZ;
                schedule_timeout_interruptible(timeout);
        }
+       /* Don't call port->drop for the last reference. Callers will want
+          to drop the last active reference in ->shutdown() or the tty
+          shutdown path */
        return 1;
 }
 EXPORT_SYMBOL(tty_port_close_start);
@@ -348,3 +370,14 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
        spin_unlock_irqrestore(&port->lock, flags);
 }
 EXPORT_SYMBOL(tty_port_close_end);
+
+void tty_port_close(struct tty_port *port, struct tty_struct *tty,
+                                                       struct file *filp)
+{
+       if (tty_port_close_start(port, tty, filp) == 0)
+               return;
+       tty_port_shutdown(port);
+       tty_port_close_end(port, tty);
+       tty_port_tty_set(port, NULL);
+}
+EXPORT_SYMBOL(tty_port_close);