USB: generic usb serial to new buffering scheme

the generic driver also had its own buffering.

Signed-off-by: Oliver Neukum <oneukum@suse.de_
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 34 insertions, 35 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index b90ef3f70f4c..b09bed4b77d3 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -281,45 +281,54 @@ int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
         return (chars);
 }
 
-/* Push data to tty layer and resubmit the bulk read URB */
-static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
+
+static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
 {
-        struct usb_serial *serial = port->serial;
         struct urb *urb = port->read_urb;
-        struct tty_struct *tty = port->tty;
+        struct usb_serial *serial = port->serial;
         int result;
 
-        /* Push data to tty */
-        if (tty && urb->actual_length) {
-                tty_buffer_request_room(tty, urb->actual_length);
-                tty_insert_flip_string(tty, urb->transfer_buffer, urb->actual_length);
-                tty_flip_buffer_push(tty); /* is this allowed from an URB callback ? */
-        }
-
         /* Continue reading from device */
-        usb_fill_bulk_urb (port->read_urb, serial->dev,
+        usb_fill_bulk_urb (urb, serial->dev,
                            usb_rcvbulkpipe (serial->dev,
                                             port->bulk_in_endpointAddress),
-                           port->read_urb->transfer_buffer,
-                           port->read_urb->transfer_buffer_length,
+                           urb->transfer_buffer,
+                           urb->transfer_buffer_length,
                            ((serial->type->read_bulk_callback) ? 
                              serial->type->read_bulk_callback : 
                              usb_serial_generic_read_bulk_callback), port);
-        result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+        result = usb_submit_urb(urb, mem_flags);
         if (result)
                 dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
 }
 
+/* Push data to tty layer and resubmit the bulk read URB */
+static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
+{
+        struct urb *urb = port->read_urb;
+        struct tty_struct *tty = port->tty;
+        int room;
+
+        /* Push data to tty */
+        if (tty && urb->actual_length) {
+                room = tty_buffer_request_room(tty, urb->actual_length);
+                if (room) {
+                        tty_insert_flip_string(tty, urb->transfer_buffer, room);
+                        tty_flip_buffer_push(tty); /* is this allowed from an URB callback ? */
+                }
+        }
+
+        resubmit_read_urb(port, GFP_ATOMIC);
+}
+
 void usb_serial_generic_read_bulk_callback (struct urb *urb)
 {
         struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
         unsigned char *data = urb->transfer_buffer;
-        int is_throttled;
-        unsigned long flags;
 
         dbg("%s - port %d", __FUNCTION__, port->number);
 
-        if (urb->status) {
+        if (unlikely(urb->status != 0)) {
                 dbg("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
                 return;
         }
@@ -327,21 +336,11 @@ void usb_serial_generic_read_bulk_callback (struct urb *urb)
         usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
 
         /* Throttle the device if requested by tty */
-        if (urb->actual_length) {
-                spin_lock_irqsave(&port->lock, flags);
-                is_throttled = port->throttled = port->throttle_req;
-                spin_unlock_irqrestore(&port->lock, flags);
-                if (is_throttled) {
-                        /* Let the received data linger in the read URB;
-                         * usb_serial_generic_unthrottle() will pick it
-                         * up later. */
-                        dbg("%s - throttling device", __FUNCTION__);
-                        return;
-                }
-        }
-
-        /* Handle data and continue reading from device */
-        flush_and_resubmit_read_urb(port);
+        spin_lock(&port->lock);
+        if (!(port->throttled = port->throttle_req))
+                /* Handle data and continue reading from device */
+                flush_and_resubmit_read_urb(port);
+        spin_unlock(&port->lock);
 }
 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 
@@ -388,8 +387,8 @@ void usb_serial_generic_unthrottle (struct usb_serial_port *port)
         spin_unlock_irqrestore(&port->lock, flags);
 
         if (was_throttled) {
-                /* Handle pending data and resume reading from device */
-                flush_and_resubmit_read_urb(port);
+                /* Resume reading from device */
+                resubmit_read_urb(port, GFP_KERNEL);
         }
 }