Commit 8c356be9 authored by Alan Cox's avatar Alan Cox Committed by Greg Kroah-Hartman

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

commit 4455e344 upstream.
Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 08f30ff9
...@@ -316,16 +316,19 @@ static void serial_do_down(struct usb_serial_port *port) ...@@ -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 * Do the resource freeing and refcount dropping for the port. We must
* be careful about ordering and we must avoid freeing up the console. * 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 usb_serial *serial;
struct module *owner; struct module *owner;
/* The console is magical, do not hang up the console hardware /* The console is magical, do not hang up the console hardware
or there will be tears */ or there will be tears */
if (port->console) if (port == NULL || port->console)
return; return;
serial = port->serial; serial = port->serial;
...@@ -350,30 +353,12 @@ static void serial_close(struct tty_struct *tty, struct file *filp) ...@@ -350,30 +353,12 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
dbg("%s - port %d", __func__, port->number); 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) if (tty_port_close_start(&port->port, tty, filp) == 0)
return; return;
serial_do_down(port); serial_do_down(port);
tty_port_close_end(&port->port, tty); tty_port_close_end(&port->port, tty);
tty_port_tty_set(&port->port, NULL); tty_port_tty_set(&port->port, NULL);
serial_do_free(port);
} }
static void serial_hangup(struct tty_struct *tty) static void serial_hangup(struct tty_struct *tty)
...@@ -1243,6 +1228,7 @@ static const struct tty_operations serial_ops = { ...@@ -1243,6 +1228,7 @@ static const struct tty_operations serial_ops = {
.chars_in_buffer = serial_chars_in_buffer, .chars_in_buffer = serial_chars_in_buffer,
.tiocmget = serial_tiocmget, .tiocmget = serial_tiocmget,
.tiocmset = serial_tiocmset, .tiocmset = serial_tiocmset,
.shutdown = serial_do_free,
.proc_fops = &serial_proc_fops, .proc_fops = &serial_proc_fops,
}; };
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment