USB: ir-usb: fix set_termios race

Use dynamically allocated urb for baudrate changes rather than
unconditionally submitting the port write urb which may already be in
use.

Compile-only tested.

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

diff --git a/drivers/usb/serial/ir-usb.c b/drivers/usb/serial/ir-usb.c
index aaebb70..d8490ea 100644 (file)
--- a/drivers/usb/serial/ir-usb.c
+++ b/drivers/usb/serial/ir-usb.c
@@ -469,9 +469,23 @@ static void ir_read_bulk_callback(struct urb *urb)
        return;
 }
 
+static void ir_set_termios_callback(struct urb *urb)
+{
+       struct usb_serial_port *port = urb->context;
+       int status = urb->status;
+
+       dbg("%s - port %d", __func__, port->number);
+
+       kfree(urb->transfer_buffer);
+
+       if (status)
+               dbg("%s - non-zero urb status: %d", __func__, status);
+}
+
 static void ir_set_termios(struct tty_struct *tty,
                struct usb_serial_port *port, struct ktermios *old_termios)
 {
+       struct urb *urb;
        unsigned char *transfer_buffer;
        int result;
        speed_t baud;
@@ -525,35 +539,52 @@ static void ir_set_termios(struct tty_struct *tty,
        else
                ir_xbof = ir_xbof_change(xbof) ;
 
-       /* FIXME need to check to see if our write urb is busy right
-        * now, or use a urb pool.
-        *
+       /* Only speed changes are supported */
+       tty_termios_copy_hw(tty->termios, old_termios);
+       tty_encode_baud_rate(tty, baud, baud);
+
+       /*
         * send the baud change out on an "empty" data packet
         */
-       transfer_buffer = port->write_urb->transfer_buffer;
+       urb = usb_alloc_urb(0, GFP_KERNEL);
+       if (!urb) {
+               dev_err(&port->dev, "%s - no more urbs\n", __func__);
+               return;
+       }
+       transfer_buffer = kmalloc(1, GFP_KERNEL);
+       if (!transfer_buffer) {
+               dev_err(&port->dev, "%s - out of memory\n", __func__);
+               goto err_buf;
+       }
+
        *transfer_buffer = ir_xbof | ir_baud;
 
        usb_fill_bulk_urb(
-               port->write_urb,
+               urb,
                port->serial->dev,
                usb_sndbulkpipe(port->serial->dev,
                        port->bulk_out_endpointAddress),
-               port->write_urb->transfer_buffer,
+               transfer_buffer,
                1,
-               ir_write_bulk_callback,
+               ir_set_termios_callback,
                port);
 
-       port->write_urb->transfer_flags = URB_ZERO_PACKET;
+       urb->transfer_flags = URB_ZERO_PACKET;
 
-       result = usb_submit_urb(port->write_urb, GFP_KERNEL);
-       if (result)
-               dev_err(&port->dev,
-                               "%s - failed submitting write urb, error %d\n",
-                               __func__, result);
+       result = usb_submit_urb(urb, GFP_KERNEL);
+       if (result) {
+               dev_err(&port->dev, "%s - failed to submit urb: %d\n",
+                                                       __func__, result);
+               goto err_subm;
+       }
 
-       /* Only speed changes are supported */
-       tty_termios_copy_hw(tty->termios, old_termios);
-       tty_encode_baud_rate(tty, baud, baud);
+       usb_free_urb(urb);
+
+       return;
+err_subm:
+       kfree(transfer_buffer);
+err_buf:
+       usb_free_urb(urb);
 }
 
 static int __init ir_init(void)