diff options
Diffstat (limited to 'drivers/usb/serial/usb-serial.c')
| -rw-r--r-- | drivers/usb/serial/usb-serial.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index d595aa5..3c8923f 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -21,6 +21,7 @@ #include <linux/errno.h> #include <linux/init.h> #include <linux/slab.h> +#include <linux/smp_lock.h> #include <linux/tty.h> #include <linux/tty_driver.h> #include <linux/tty_flip.h> @@ -220,7 +221,8 @@ static int serial_open (struct tty_struct *tty, struct file *filp) tty->driver_data = port; tty_port_tty_set(&port->port, tty); - if (port->port.count == 1) { + /* If the console is attached, the device is already open */ + if (port->port.count == 1 && !port->console) { /* lock this module before we call it * this may fail, which means we must bail out, @@ -333,8 +335,27 @@ 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); + /* 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; @@ -350,7 +371,8 @@ static void serial_hangup(struct tty_struct *tty) struct usb_serial_port *port = tty->driver_data; serial_do_down(port); tty_port_hangup(&port->port); - serial_do_free(port); + /* We must not free port yet - the USB serial layer depends on it's + continued existence */ } static int serial_write(struct tty_struct *tty, const unsigned char *buf, |