[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, 12 insertions, 5 deletions

diff --git a/drivers/usb/serial/omninet.c b/drivers/usb/serial/omninet.c
index b5f2c06d4f3e..6a99ae192df1 100644
--- a/drivers/usb/serial/omninet.c
+++ b/drivers/usb/serial/omninet.c
@@ -254,10 +254,15 @@ static int omninet_write (struct usb_serial_port *port, const unsigned char *buf
                 dbg("%s - write request of 0 bytes", __FUNCTION__);
                 return (0);
         }
-        if (wport->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);
 
         count = (count > OMNINET_BULKOUTSIZE) ? OMNINET_BULKOUTSIZE : count;
 
@@ -275,9 +280,10 @@ static int omninet_write (struct usb_serial_port *port, const unsigned char *buf
 
         wport->write_urb->dev = serial->dev;
         result = usb_submit_urb(wport->write_urb, GFP_ATOMIC);
-        if (result)
+        if (result) {
+                port->write_urb_busy = 0;
                 err("%s - failed submitting write urb, error %d", __FUNCTION__, result);
-        else
+        } else
                 result = count;
 
         return result;
@@ -291,7 +297,7 @@ static int omninet_write_room (struct usb_serial_port *port)
 
         int room = 0; // Default: no room
 
-        if (wport->write_urb->status != -EINPROGRESS)
+        if (wport->write_urb_busy)
                 room = wport->bulk_out_size - OMNINET_HEADERLEN;
 
 //      dbg("omninet_write_room returns %d", room);
@@ -306,6 +312,7 @@ static void omninet_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
 
 //      dbg("omninet_write_bulk_callback, port %0x\n", port);
 
+        port->write_urb_busy = 0;
         if (urb->status) {
                 dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
                 return;