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>

1 files changed, 17 insertions, 4 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 28125de7d902..9a3258046c8c 100644
--- 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);