USB: serial: use urb poison to reliably kill traffic

Use usb_poison_urb to reliably kill all urbs on disconnect and suspend.

This way there will be no question that the urbs cannot be resubmitted
by buggy subdrivers.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index db0b646..0b39d01 100644 (file)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -542,27 +542,30 @@ static void usb_serial_port_work(struct work_struct *work)
        tty_kref_put(tty);
 }
 
-static void kill_traffic(struct usb_serial_port *port)
+static void usb_serial_port_poison_urbs(struct usb_serial_port *port)
 {
        int i;
 
        for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
-               usb_kill_urb(port->read_urbs[i]);
+               usb_poison_urb(port->read_urbs[i]);
        for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
-               usb_kill_urb(port->write_urbs[i]);
-       /*
-        * This is tricky.
-        * Some drivers submit the read_urb in the
-        * handler for the write_urb or vice versa
-        * this order determines the order in which
-        * usb_kill_urb() must be used to reliably
-        * kill the URBs. As it is unknown here,
-        * both orders must be used in turn.
-        * The call below is not redundant.
-        */
-       usb_kill_urb(port->read_urb);
-       usb_kill_urb(port->interrupt_in_urb);
-       usb_kill_urb(port->interrupt_out_urb);
+               usb_poison_urb(port->write_urbs[i]);
+
+       usb_poison_urb(port->interrupt_in_urb);
+       usb_poison_urb(port->interrupt_out_urb);
+}
+
+static void usb_serial_port_unpoison_urbs(struct usb_serial_port *port)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
+               usb_unpoison_urb(port->read_urbs[i]);
+       for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
+               usb_unpoison_urb(port->write_urbs[i]);
+
+       usb_unpoison_urb(port->interrupt_in_urb);
+       usb_unpoison_urb(port->interrupt_out_urb);
 }
 
 static void usb_serial_port_release(struct device *dev)
@@ -1082,7 +1085,7 @@ static void usb_serial_disconnect(struct usb_interface *interface)
                                tty_vhangup(tty);
                                tty_kref_put(tty);
                        }
-                       kill_traffic(port);
+                       usb_serial_port_poison_urbs(port);
                        cancel_work_sync(&port->work);
                        if (device_is_registered(&port->dev))
                                device_del(&port->dev);
@@ -1120,7 +1123,7 @@ int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
        for (i = 0; i < serial->num_ports; ++i) {
                port = serial->port[i];
                if (port)
-                       kill_traffic(port);
+                       usb_serial_port_poison_urbs(port);
        }
 
 err_out:
@@ -1128,11 +1131,25 @@ err_out:
 }
 EXPORT_SYMBOL(usb_serial_suspend);
 
+static void usb_serial_unpoison_port_urbs(struct usb_serial *serial)
+{
+       struct usb_serial_port *port;
+       int i;
+
+       for (i = 0; i < serial->num_ports; ++i) {
+               port = serial->port[i];
+               if (port)
+                       usb_serial_port_unpoison_urbs(port);
+       }
+}
+
 int usb_serial_resume(struct usb_interface *intf)
 {
        struct usb_serial *serial = usb_get_intfdata(intf);
        int rv;
 
+       usb_serial_unpoison_port_urbs(serial);
+
        serial->suspending = 0;
        if (serial->type->resume)
                rv = serial->type->resume(serial);
@@ -1148,6 +1165,8 @@ static int usb_serial_reset_resume(struct usb_interface *intf)
        struct usb_serial *serial = usb_get_intfdata(intf);
        int rv;
 
+       usb_serial_unpoison_port_urbs(serial);
+
        serial->suspending = 0;
        if (serial->type->reset_resume)
                rv = serial->type->reset_resume(serial);