From 320348c8d5c9b591282633ddb8959b42f7fc7a1c Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 1 Sep 2009 11:39:59 -0400 Subject: [PATCH] usb-serial: straighten out serial_open This patch (as1291) removes a bunch of code from serial_open(), things that were rendered unnecessary by earlier patches. A missing spinlock is added to protect port->port.count, which needs to be incremented even if the open fails but not if the tty has gotten a hangup. The test for whether the hardware has been initialized, based on the use count, is replaced by a more transparent test of the ASYNCB_INITIALIZED bit in the port flags. Signed-off-by: Alan Stern Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/usb-serial.c | 59 +++++++++++++++-------------------------- 1 file changed, 22 insertions(+), 37 deletions(-) diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 9a32580..9d7ca48 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -245,55 +245,40 @@ static int serial_install(struct tty_driver *driver, struct tty_struct *tty) return retval; } -static int serial_open (struct tty_struct *tty, struct file *filp) +static int serial_open(struct tty_struct *tty, struct file *filp) { - struct usb_serial *serial; - struct usb_serial_port *port; - int retval = 0; - int first = 0; - - port = tty->driver_data; - serial = port->serial; + struct usb_serial_port *port = tty->driver_data; + struct usb_serial *serial = port->serial; + int retval; dbg("%s - port %d", __func__, port->number); - if (mutex_lock_interruptible(&port->mutex)) - return -ERESTARTSYS; - - ++port->port.count; + spin_lock_irq(&port->port.lock); + if (!tty_hung_up_p(filp)) + ++port->port.count; + spin_unlock_irq(&port->port.lock); tty_port_tty_set(&port->port, tty); - /* If the console is attached, the device is already open */ - if (port->port.count == 1 && !port->console) { - first = 1; + /* Do the device-specific open only if the hardware isn't + * already initialized. + */ + if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) { + if (mutex_lock_interruptible(&port->mutex)) + return -ERESTARTSYS; mutex_lock(&serial->disc_mutex); - - /* only call the device specific open if this - * is the first time the port is opened */ - retval = serial->type->open(tty, port); - if (retval) - goto bailout_module_put; + if (serial->disconnected) + retval = -ENODEV; + else + retval = port->serial->type->open(tty, port); mutex_unlock(&serial->disc_mutex); + mutex_unlock(&port->mutex); + if (retval) + return retval; set_bit(ASYNCB_INITIALIZED, &port->port.flags); } - mutex_unlock(&port->mutex); + /* Now do the correct tty layer semantics */ retval = tty_port_block_til_ready(&port->port, tty, filp); - if (retval == 0) { - if (!first) - usb_serial_put(serial); - return 0; - } - mutex_lock(&port->mutex); - if (first == 0) - goto bailout_mutex_unlock; - /* Undo the initial port actions */ - mutex_lock(&serial->disc_mutex); -bailout_module_put: - mutex_unlock(&serial->disc_mutex); -bailout_mutex_unlock: - port->port.count = 0; - mutex_unlock(&port->mutex); return retval; } -- 2.7.4