diff options
| author | Alan Cox <alan@linux.intel.com> | 2009-09-19 13:13:24 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-10-05 09:32:36 -0700 |
| commit | 8c356be946801075b40ac8c234d5b34e9dd06c55 (patch) | |
| tree | c503f2f94507850e06457c41fd50f12ccf106b9e | |
| parent | 08f30ff9811e59c08d1cee043ce55b2e862efe58 (diff) | |
tty: USB can now use the shutdown method for kref based freeing of ports
commit 4455e344959a217ffc28de2ab1af87541322b343 upstream.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/serial/usb-serial.c | 28 |
1 files changed, 7 insertions, 21 deletions
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 21dd72a5a715..31c7a0939b98 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -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, }; |