Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1abdeeb1d566f74bc5b3e68447d91c8c37d47942
Commit:     1abdeeb1d566f74bc5b3e68447d91c8c37d47942
Parent:     39892da44b21b5362eb848ca424d73a25ccc488f
Author:     Oliver Neukum <[EMAIL PROTECTED]>
AuthorDate: Mon May 7 12:09:33 2007 +0200
Committer:  Greg Kroah-Hartman <[EMAIL PROTECTED]>
CommitDate: Thu Jul 12 16:29:51 2007 -0700

    USB: generic usb serial to new buffering scheme
    
    the generic driver also had its own buffering.
    
    Signed-off-by: Oliver Neukum <[EMAIL PROTECTED]
    Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
 drivers/usb/serial/generic.c |   69 ++++++++++++++++++++---------------------
 1 files changed, 34 insertions(+), 35 deletions(-)

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index b90ef3f..b09bed4 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);
        }
 }
 
-
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