[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.

This removes a lot of racy and buggy code by trying to check the status of the urb.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 10 insertions, 9 deletions

diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index 46a204cd40e..b5b431067b0 100644
--- a/drivers/usb/serial/cyberjack.c
+++ b/drivers/usb/serial/cyberjack.c
@@ -213,10 +213,14 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 		return (0);
 	}
 
-	if (port->write_urb->status == -EINPROGRESS) {
+	spin_lock(&port->lock);
+	if (port->write_urb_busy) {
+		spin_unlock(&port->lock);
 		dbg("%s - already writing", __FUNCTION__);
-		return (0);
+		return 0;
 	}
+	port->write_urb_busy = 1;
+	spin_unlock(&port->lock);
 
 	spin_lock_irqsave(&priv->lock, flags);
 
@@ -224,6 +228,7 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 		/* To much data for buffer. Reset buffer. */
 		priv->wrfilled=0;
 		spin_unlock_irqrestore(&priv->lock, flags);
+		port->write_urb_busy = 0;
 		return (0);
 	}
 
@@ -268,6 +273,7 @@ static int cyberjack_write (struct usb_serial_port *port, const unsigned char *b
 			priv->wrfilled=0;
 			priv->wrsent=0;
 			spin_unlock_irqrestore(&priv->lock, flags);
+			port->write_urb_busy = 0;
 			return 0;
 		}
 
@@ -412,7 +418,8 @@ static void cyberjack_write_bulk_callback (struct urb *urb, struct pt_regs *regs
 	struct cyberjack_private *priv = usb_get_serial_port_data(port);
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
-	
+
+	port->write_urb_busy = 0;
 	if (urb->status) {
 		dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
 		return;
@@ -424,12 +431,6 @@ static void cyberjack_write_bulk_callback (struct urb *urb, struct pt_regs *regs
 	if( priv->wrfilled ) {
 		int length, blksize, result;
 
-		if (port->write_urb->status == -EINPROGRESS) {
-			dbg("%s - already writing", __FUNCTION__);
-			spin_unlock(&priv->lock);
-			return;
-		}
-
 		dbg("%s - transmitting data (frame n)", __FUNCTION__);
 
 		length = ((priv->wrfilled - priv->wrsent) > port->bulk_out_size) ?