[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 46a204cd40e1..b5b431067b08 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) ?