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tty: USB can now use the shutdown method for kref based freeing of ports 

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Cox 2009-09-19 13:13:24 -07:00 committed by Live-CD User
parent 9a68e39d4a
commit 4455e34495
1 changed files with 7 additions and 21 deletions
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28
drivers/usb/serial/usb-serial.c
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@ -316,16 +316,19 @@ static void serial_do_down(struct usb_serial_port *port)
*
* Do the resource freeing and refcount dropping for the port. We must
* be careful about ordering and we must avoid freeing up the console.
*
* Called when the last tty kref is dropped.
*/
static void serial_do_free(struct usb_serial_port *port)
static void serial_do_free(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
struct usb_serial *serial;
struct module *owner;
/* The console is magical, do not hang up the console hardware
or there will be tears */
if (port->console)
if (port == NULL || port->console)
return;
serial = port->serial;
@ -350,30 +353,12 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
dbg("%s - port %d", __func__, port->number);
/* FIXME:
This leaves a very narrow race. Really we should do the
serial_do_free() on tty->shutdown(), but tty->shutdown can
be called from IRQ context and serial_do_free can sleep.
The right fix is probably to make the tty free (which is rare)
and thus tty->shutdown() occur via a work queue and simplify all
the drivers that use it.
*/
if (tty_hung_up_p(filp)) {
/* serial_hangup already called serial_down at this point.
Another user may have already reopened the port but
serial_do_free is refcounted */
serial_do_free(port);
return;
}
if (tty_port_close_start(&port->port, tty, filp) == 0)
return;
serial_do_down(port);
tty_port_close_end(&port->port, tty);
tty_port_tty_set(&port->port, NULL);
serial_do_free(port);
}
static void serial_hangup(struct tty_struct *tty)
@ -1243,6 +1228,7 @@ static const struct tty_operations serial_ops = {
.chars_in_buffer = serial_chars_in_buffer,
.tiocmget = serial_tiocmget,
.tiocmset = serial_tiocmset,
.shutdown = serial_do_free,
.proc_fops = &serial_proc_fops,
};