diff options
| -rw-r--r-- | drivers/usb/serial/usb-serial.c | 111 |
1 files changed, 47 insertions, 64 deletions
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 87802ea8bbc..7d207d91a6a 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -187,100 +187,92 @@ void usb_serial_put(struct usb_serial *serial) * Create the termios objects for this tty. We use the default * USB serial settings but permit them to be overridden by * serial->type->init_termios. + * + * This is the first place a new tty gets used. Hence this is where we + * acquire references to the usb_serial structure and the driver module, + * where we store a pointer to the port, and where we do an autoresume. + * All these actions are reversed in serial_do_free(). */ static int serial_install(struct tty_driver *driver, struct tty_struct *tty) { int idx = tty->index; struct usb_serial *serial; - int retval; + struct usb_serial_port *port; + int retval = -ENODEV; + + serial = usb_serial_get_by_index(idx); + if (!serial) + return retval; + + port = serial->port[idx - serial->minor]; + if (!port) + goto error_no_port; + if (!try_module_get(serial->type->driver.owner)) + goto error_module_get; + + retval = usb_autopm_get_interface(serial->interface); + if (retval) + goto error_get_interface; /* If the termios setup has yet to be done */ if (tty->driver->termios[idx] == NULL) { /* perform the standard setup */ retval = tty_init_termios(tty); if (retval) - return retval; + goto error_init_termios; /* allow the driver to update it */ - serial = usb_serial_get_by_index(tty->index); - if (serial) { - if (serial->type->init_termios) - serial->type->init_termios(tty); - usb_serial_put(serial); - mutex_unlock(&serial->disc_mutex); - } + if (serial->type->init_termios) + serial->type->init_termios(tty); } + mutex_unlock(&serial->disc_mutex); + + tty->driver_data = port; + /* Final install (we use the default method) */ tty_driver_kref_get(driver); tty->count++; driver->ttys[idx] = tty; - return 0; + return retval; + + error_init_termios: + usb_autopm_put_interface(serial->interface); + error_get_interface: + module_put(serial->type->driver.owner); + error_module_get: + error_no_port: + usb_serial_put(serial); + mutex_unlock(&serial->disc_mutex); + return retval; } static int serial_open (struct tty_struct *tty, struct file *filp) { struct usb_serial *serial; struct usb_serial_port *port; - unsigned int portNumber; int retval = 0; int first = 0; dbg("%s", __func__); - /* get the serial object associated with this tty pointer */ - serial = usb_serial_get_by_index(tty->index); - if (!serial) { - tty->driver_data = NULL; - return -ENODEV; - } - - portNumber = tty->index - serial->minor; - port = serial->port[portNumber]; - if (!port || serial->disconnected) - retval = -ENODEV; - /* - * Note: Our locking order requirement does not allow port->mutex - * to be acquired while serial->disc_mutex is held. - */ - mutex_unlock(&serial->disc_mutex); - if (retval) - goto bailout_serial_put; + port = tty->driver_data; + serial = port->serial; - if (mutex_lock_interruptible(&port->mutex)) { - retval = -ERESTARTSYS; - goto bailout_serial_put; - } + if (mutex_lock_interruptible(&port->mutex)) + return -ERESTARTSYS; ++port->port.count; - - /* set up our port structure making the tty driver - * remember our port object, and us it */ - tty->driver_data = port; 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; - /* lock this module before we call it - * this may fail, which means we must bail out, - * safe because we are called with BKL held */ - if (!try_module_get(serial->type->driver.owner)) { - retval = -ENODEV; - goto bailout_mutex_unlock; - } - mutex_lock(&serial->disc_mutex); - if (serial->disconnected) - retval = -ENODEV; - else - retval = usb_autopm_get_interface(serial->interface); - if (retval) - goto bailout_module_put; /* 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_interface_put; + goto bailout_module_put; mutex_unlock(&serial->disc_mutex); set_bit(ASYNCB_INITIALIZED, &port->port.flags); } @@ -297,18 +289,11 @@ static int serial_open (struct tty_struct *tty, struct file *filp) goto bailout_mutex_unlock; /* Undo the initial port actions */ mutex_lock(&serial->disc_mutex); -bailout_interface_put: - usb_autopm_put_interface(serial->interface); bailout_module_put: mutex_unlock(&serial->disc_mutex); - module_put(serial->type->driver.owner); bailout_mutex_unlock: port->port.count = 0; - tty->driver_data = NULL; - tty_port_tty_set(&port->port, NULL); mutex_unlock(&port->mutex); -bailout_serial_put: - usb_serial_put(serial); return retval; } @@ -355,9 +340,6 @@ static void serial_close(struct tty_struct *tty, struct file *filp) { struct usb_serial_port *port = tty->driver_data; - if (!port) - return; - dbg("%s - port %d", __func__, port->number); if (tty_port_close_start(&port->port, tty, filp) == 0) @@ -365,7 +347,6 @@ static void serial_close(struct tty_struct *tty, struct file *filp) serial_do_down(port); tty_port_close_end(&port->port, tty); tty_port_tty_set(&port->port, NULL); - } /** @@ -386,9 +367,11 @@ static void serial_do_free(struct tty_struct *tty) /* The console is magical. Do not hang up the console hardware * or there will be tears. */ - if (port == NULL || port->console) + if (port->console) return; + tty->driver_data = NULL; + serial = port->serial; owner = serial->type->driver.owner; |