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tty_port: add "tty_port_open" helper

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For the moment this just moves the USB logic over and fixes the 'what if
we open and hangup at the same time' race noticed by Oliver Neukum.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox
2009-10-06 16:06:11 +01:00
committed by Greg Kroah-Hartman
parent 894cb91770
commit 64bc397914
3 changed files with 65 additions and 32 deletions
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51
drivers/usb/serial/usb-serial.c
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@@ -247,43 +247,33 @@ 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_activate(struct tty_port *tport, struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
struct usb_serial_port *port =
container_of(tport, struct usb_serial_port, port);
struct usb_serial *serial = port->serial;
int retval;
dbg("%s - port %d", __func__, port->number);
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);
/* 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);
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);
}
/* Now do the correct tty layer semantics */
retval = tty_port_block_til_ready(&port->port, tty, filp);
if (mutex_lock_interruptible(&port->mutex))
return -ERESTARTSYS;
mutex_lock(&serial->disc_mutex);
if (serial->disconnected)
retval = -ENODEV;
else
retval = port->serial->type->open(tty, port);
mutex_unlock(&serial->disc_mutex);
mutex_unlock(&port->mutex);
return retval;
}
static int serial_open(struct tty_struct *tty, struct file *filp)
{
struct usb_serial_port *port = tty->driver_data;
dbg("%s - port %d", __func__, port->number);
return tty_port_open(&port->port, tty, filp);
}
/**
* serial_down - shut down hardware
* @port: port to shut down
@@ -725,6 +715,7 @@ static void serial_dtr_rts(struct tty_port *port, int on)
static const struct tty_port_operations serial_port_ops = {
.carrier_raised = serial_carrier_raised,
.dtr_rts = serial_dtr_rts,
.activate = serial_activate,
};
int usb_serial_probe(struct usb_interface *interface,