1 files changed, 39 insertions, 20 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 1a134f9c64f3..3ae17840175c 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -1,6 +1,7 @@
 /*
  * USB Serial Converter Generic functions
  *
+ * Copyright (C) 2010 Johan Hovold (jhovold@gmail.com)
  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
  *
  *      This program is free software; you can redistribute it and/or
@@ -143,6 +144,7 @@ static void generic_cleanup(struct usb_serial_port *port)
 {
         struct usb_serial *serial = port->serial;
         unsigned long flags;
+        int i;
 
         dbg("%s - port %d", __func__, port->number);
 
@@ -150,6 +152,8 @@ static void generic_cleanup(struct usb_serial_port *port)
                 /* shutdown any bulk transfers that might be going on */
                 if (port->bulk_out_size) {
                         usb_kill_urb(port->write_urb);
+                        for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
+                                usb_kill_urb(port->write_urbs[i]);
 
                         spin_lock_irqsave(&port->lock, flags);
                         kfifo_reset_out(&port->write_fifo);
@@ -258,46 +262,56 @@ err_urb:
  * usb_serial_generic_write_start - kick off an URB write
  * @port:       Pointer to the &struct usb_serial_port data
  *
- * Returns the number of bytes queued on success. This will be zero if there
- * was nothing to send. Otherwise, it returns a negative errno value
+ * Returns zero on success, or a negative errno value
  */
 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 {
-        int result;
-        int count;
+        struct urb *urb;
+        int count, result;
         unsigned long flags;
+        int i;
 
+        if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
+                return 0;
+retry:
         spin_lock_irqsave(&port->lock, flags);
-        if (port->write_urb_busy || !kfifo_len(&port->write_fifo)) {
+        if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
+                clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
                 spin_unlock_irqrestore(&port->lock, flags);
                 return 0;
         }
-        port->write_urb_busy = 1;
+        i = (int)find_first_bit(&port->write_urbs_free,
+                                                ARRAY_SIZE(port->write_urbs));
         spin_unlock_irqrestore(&port->lock, flags);
 
+        urb = port->write_urbs[i];
         count = port->serial->type->prepare_write_buffer(port,
-                                        &port->write_urb->transfer_buffer,
-                                        port->bulk_out_size, NULL, 0);
-        usb_serial_debug_data(debug, &port->dev, __func__,
-                                count, port->write_urb->transfer_buffer);
-        port->write_urb->transfer_buffer_length = count;
-
-        /* send the data out the bulk port */
-        result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
+                                                &urb->transfer_buffer,
+                                                port->bulk_out_size, NULL, 0);
+        urb->transfer_buffer_length = count;
+        usb_serial_debug_data(debug, &port->dev, __func__, count,
+                                                urb->transfer_buffer);
+        result = usb_submit_urb(urb, GFP_ATOMIC);
         if (result) {
                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
                                                 __func__, result);
-                /* don't have to grab the lock here, as we will
-                   retry if != 0 */
-                port->write_urb_busy = 0;
+                clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
                 return result;
         }
+        clear_bit(i, &port->write_urbs_free);
 
         spin_lock_irqsave(&port->lock, flags);
         port->tx_bytes += count;
         spin_unlock_irqrestore(&port->lock, flags);
 
-        return count;
+        /* Try sending off another urb, unless in irq context (in which case
+         * there will be no free urb). */
+        if (!in_irq())
+                goto retry;
+
+        clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
+
+        return 0;
 }
 
 /**
@@ -461,6 +475,7 @@ void usb_serial_generic_write_bulk_callback(struct urb *urb)
         unsigned long flags;
         struct usb_serial_port *port = urb->context;
         int status = urb->status;
+        int i;
 
         dbg("%s - port %d", __func__, port->number);
 
@@ -472,9 +487,13 @@ void usb_serial_generic_write_bulk_callback(struct urb *urb)
                 port->tx_urbs--;
                 spin_unlock_irqrestore(&port->lock, flags);
         } else {
+                for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
+                        if (port->write_urbs[i] == urb)
+                                break;
+
                 spin_lock_irqsave(&port->lock, flags);
                 port->tx_bytes -= urb->transfer_buffer_length;
-                port->write_urb_busy = 0;
+                set_bit(i, &port->write_urbs_free);
                 spin_unlock_irqrestore(&port->lock, flags);
 
                 if (status) {
@@ -576,7 +595,7 @@ int usb_serial_generic_resume(struct usb_serial *serial)
                                 c++;
                 }
 
-                if (port->write_urb) {
+                if (port->bulk_out_size) {
                         r = usb_serial_generic_write_start(port);
                         if (r < 0)
                                 c++;