usb-serial: add missing tests and debug lines

This patch (as1290) adds some missing tests.  serial_down() isn't
supposed to do anything if the hardware hasn't been initialized, and
serial_close() isn't supposed to do anything if the tty has gotten a
hangup (because serial_hangup() takes care of shutting down the
hardware).

The patch also updates and adds a few debugging lines.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 28125de..9a32580 100644 (file)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -200,6 +200,8 @@ static int serial_install(struct tty_driver *driver, struct tty_struct *tty)
        struct usb_serial_port *port;
        int retval = -ENODEV;
 
+       dbg("%s", __func__);
+
        serial = usb_serial_get_by_index(idx);
        if (!serial)
                return retval;
@@ -250,11 +252,11 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
        int retval = 0;
        int first = 0;
 
-       dbg("%s", __func__);
-
        port = tty->driver_data;
        serial = port->serial;
 
+       dbg("%s - port %d", __func__, port->number);
+
        if (mutex_lock_interruptible(&port->mutex))
                return -ERESTARTSYS;
 
@@ -315,6 +317,12 @@ static void serial_down(struct usb_serial_port *port)
        if (port->console)
                return;
 
+       /* Don't call the close method if the hardware hasn't been
+        * initialized.
+        */
+       if (!test_and_clear_bit(ASYNCB_INITIALIZED, &port->port.flags))
+               return;
+
        mutex_lock(&port->mutex);
        serial = port->serial;
        owner = serial->type->driver.owner;
@@ -328,10 +336,11 @@ static void serial_down(struct usb_serial_port *port)
 static void serial_hangup(struct tty_struct *tty)
 {
        struct usb_serial_port *port = tty->driver_data;
+
+       dbg("%s - port %d", __func__, port->number);
+
        serial_down(port);
        tty_port_hangup(&port->port);
-       /* We must not free port yet - the USB serial layer depends on it's
-          continued existence */
 }
 
 static void serial_close(struct tty_struct *tty, struct file *filp)
@@ -340,6 +349,8 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 
        dbg("%s - port %d", __func__, port->number);
 
+       if (tty_hung_up_p(filp))
+               return;
        if (tty_port_close_start(&port->port, tty, filp) == 0)
                return;
        serial_down(port);
@@ -368,6 +379,8 @@ static void serial_release(struct tty_struct *tty)
        if (port->console)
                return;
 
+       dbg("%s - port %d", __func__, port->number);
+
        /* Standard shutdown processing */
        tty_shutdown(tty);