USB: sierra: remove incorrect usage of the urb status field

You can't rely on the fact that the status really is correct like it was.

Also simplified the write path and now we allocate the urb and data on
the fly, instead of trying to do that really odd timeout check which I
am guessing doesn't really work properly.  This should speed up the
device by keeping the hardware queue full easier.

As a benefit, this reduces the size of the driver.

Cc: Kevin Lloyd <linux@sierrawireless.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/sierra.c

@@ -86,15 +86,14 @@ static int debug;
 #define N_IN_URB	4
 #define N_OUT_URB	4
 #define IN_BUFLEN	4096
-#define OUT_BUFLEN	128
 
 struct sierra_port_private {
+	spinlock_t lock;	/* lock the structure */
+	int outstanding_urbs;	/* number of out urbs in flight */
+
 	/* Input endpoints and buffer for this port */
 	struct urb *in_urbs[N_IN_URB];
 	char in_buffer[N_IN_URB][IN_BUFLEN];
-	/* Output endpoints and buffer for this port */
-	struct urb *out_urbs[N_OUT_URB];
-	char out_buffer[N_OUT_URB][OUT_BUFLEN];
 
 	/* Settings for the port */
 	int rts_state;	/* Handshaking pins (outputs) */
@@ -103,8 +102,6 @@ struct sierra_port_private {
 	int dsr_state;
 	int dcd_state;
 	int ri_state;
-
-	unsigned long tx_start_time[N_OUT_URB];
 };
 
 static int sierra_send_setup(struct usb_serial_port *port)
@@ -197,61 +194,98 @@ static int sierra_ioctl(struct usb_serial_port *port, struct file *file,
 	return -ENOIOCTLCMD;
 }
 
+static void sierra_outdat_callback(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	struct sierra_port_private *portdata = usb_get_serial_port_data(port);
+	int status = urb->status;
+	unsigned long flags;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/* free up the transfer buffer, as usb_free_urb() does not do this */
+	kfree(urb->transfer_buffer);
+
+	if (status)
+		dbg("%s - nonzero write bulk status received: %d",
+		    __FUNCTION__, status);
+
+	spin_lock_irqsave(&portdata->lock, flags);
+	--portdata->outstanding_urbs;
+	spin_unlock_irqrestore(&portdata->lock, flags);
+
+	usb_serial_port_softint(port);
+}
+
 /* Write */
 static int sierra_write(struct usb_serial_port *port,
 			const unsigned char *buf, int count)
 {
-	struct sierra_port_private *portdata;
-	int i;
-	int left, todo;
-	struct urb *this_urb = NULL; /* spurious */
-	int err;
+	struct sierra_port_private *portdata = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	unsigned long flags;
+	unsigned char *buffer;
+	struct urb *urb;
+	int status;
 
 	portdata = usb_get_serial_port_data(port);
 
 	dbg("%s: write (%d chars)", __FUNCTION__, count);
 
-	i = 0;
-	left = count;
-	for (i=0; left > 0 && i < N_OUT_URB; i++) {
-		todo = left;
-		if (todo > OUT_BUFLEN)
-			todo = OUT_BUFLEN;
-
-		this_urb = portdata->out_urbs[i];
-		if (this_urb->status == -EINPROGRESS) {
-			if (time_before(jiffies,
-					portdata->tx_start_time[i] + 10 * HZ))
-				continue;
-			usb_unlink_urb(this_urb);
-			continue;
-		}
-		if (this_urb->status != 0)
-			dbg("usb_write %p failed (err=%d)",
-				this_urb, this_urb->status);
+	spin_lock_irqsave(&portdata->lock, flags);
+	if (portdata->outstanding_urbs > N_OUT_URB) {
+		spin_unlock_irqrestore(&portdata->lock, flags);
+		dbg("%s - write limit hit\n", __FUNCTION__);
+		return 0;
+	}
+	portdata->outstanding_urbs++;
+	spin_unlock_irqrestore(&portdata->lock, flags);
+
+	buffer = kmalloc(count, GFP_ATOMIC);
+	if (!buffer) {
+		dev_err(&port->dev, "out of memory\n");
+		count = -ENOMEM;
+		goto error_no_buffer;
+	}
 
-		dbg("%s: endpoint %d buf %d", __FUNCTION__,
-			usb_pipeendpoint(this_urb->pipe), i);
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		dev_err(&port->dev, "no more free urbs\n");
+		count = -ENOMEM;
+		goto error_no_urb;
+	}
 
-		/* send the data */
-		memcpy (this_urb->transfer_buffer, buf, todo);
-		this_urb->transfer_buffer_length = todo;
+	memcpy(buffer, buf, count);
 
-		this_urb->dev = port->serial->dev;
-		err = usb_submit_urb(this_urb, GFP_ATOMIC);
-		if (err) {
-			dbg("usb_submit_urb %p (write bulk) failed "
-				"(%d, has %d)", this_urb,
-				err, this_urb->status);
-			continue;
-		}
-		portdata->tx_start_time[i] = jiffies;
-		buf += todo;
-		left -= todo;
+	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buffer);
+
+	usb_fill_bulk_urb(urb, serial->dev,
+			  usb_sndbulkpipe(serial->dev,
+					  port->bulk_out_endpointAddress),
+			  buffer, count, sierra_outdat_callback, port);
+
+	/* send it down the pipe */
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+	if (status) {
+		dev_err(&port->dev, "%s - usb_submit_urb(write bulk) failed "
+			"with status = %d\n", __FUNCTION__, status);
+		count = status;
+		goto error;
 	}
 
-	count -= left;
-	dbg("%s: wrote (did %d)", __FUNCTION__, count);
+	/* we are done with this urb, so let the host driver
+	 * really free it when it is finished with it */
+	usb_free_urb(urb);
+
+	return count;
+error:
+	usb_free_urb(urb);
+error_no_urb:
+	kfree(buffer);
+error_no_buffer:
+	spin_lock_irqsave(&portdata->lock, flags);
+	--portdata->outstanding_urbs;
+	spin_unlock_irqrestore(&portdata->lock, flags);
 	return count;
 }
 
@@ -286,24 +320,13 @@ static void sierra_indat_callback(struct urb *urb)
 		if (port->open_count && status != -ESHUTDOWN) {
 			err = usb_submit_urb(urb, GFP_ATOMIC);
 			if (err)
-				printk(KERN_ERR "%s: resubmit read urb failed. "
-					"(%d)", __FUNCTION__, err);
+				dev_err(&port->dev, "resubmit read urb failed."
+					"(%d)", err);
 		}
 	}
 	return;
 }
 
-static void sierra_outdat_callback(struct urb *urb)
-{
-	struct usb_serial_port *port;
-
-	dbg("%s", __FUNCTION__);
-
-	port = (struct usb_serial_port *) urb->context;
-
-	usb_serial_port_softint(port);
-}
-
 static void sierra_instat_callback(struct urb *urb)
 {
 	int err;
@@ -360,39 +383,35 @@ static void sierra_instat_callback(struct urb *urb)
 
 static int sierra_write_room(struct usb_serial_port *port)
 {
-	struct sierra_port_private *portdata;
-	int i;
-	int data_len = 0;
-	struct urb *this_urb;
+	struct sierra_port_private *portdata = usb_get_serial_port_data(port);
+	unsigned long flags;
 
-	portdata = usb_get_serial_port_data(port);
+	dbg("%s - port %d", __FUNCTION__, port->number);
 
-	for (i=0; i < N_OUT_URB; i++) {
-		this_urb = portdata->out_urbs[i];
-		if (this_urb && this_urb->status != -EINPROGRESS)
-			data_len += OUT_BUFLEN;
+	/* try to give a good number back based on if we have any free urbs at
+	 * this point in time */
+	spin_lock_irqsave(&portdata->lock, flags);
+	if (portdata->outstanding_urbs > N_OUT_URB * 2 / 3) {
+		spin_unlock_irqrestore(&portdata->lock, flags);
+		dbg("%s - write limit hit\n", __FUNCTION__);
+		return 0;
 	}
+	spin_unlock_irqrestore(&portdata->lock, flags);
 
-	dbg("%s: %d", __FUNCTION__, data_len);
-	return data_len;
+	return 2048;
 }
 
 static int sierra_chars_in_buffer(struct usb_serial_port *port)
 {
-	struct sierra_port_private *portdata;
-	int i;
-	int data_len = 0;
-	struct urb *this_urb;
-
-	portdata = usb_get_serial_port_data(port);
-
-	for (i=0; i < N_OUT_URB; i++) {
-		this_urb = portdata->out_urbs[i];
-		if (this_urb && this_urb->status == -EINPROGRESS)
-			data_len += this_urb->transfer_buffer_length;
-	}
-	dbg("%s: %d", __FUNCTION__, data_len);
-	return data_len;
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/*
+	 * We can't really account for how much data we
+	 * have sent out, but hasn't made it through to the
+	 * device as we can't see the backend here, so just
+	 * tell the tty layer that everything is flushed.
+	 */
+	return 0;
 }
 
 static int sierra_open(struct usb_serial_port *port, struct file *filp)
@@ -437,16 +456,6 @@ static int sierra_open(struct usb_serial_port *port, struct file *filp)
 		}
 	}
 
-	/* Reset low level data toggle on out endpoints */
-	for (i = 0; i < N_OUT_URB; i++) {
-		urb = portdata->out_urbs[i];
-		if (! urb)
-			continue;
-		urb->dev = serial->dev;
-		/* usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe),
-				usb_pipeout(urb->pipe), 0); */
-	}
-
 	port->tty->low_latency = 1;
 
 	/* set mode to D0 */
@@ -478,8 +487,6 @@ static void sierra_close(struct usb_serial_port *port, struct file *filp)
 		/* Stop reading/writing urbs */
 		for (i = 0; i < N_IN_URB; i++)
 			usb_unlink_urb(portdata->in_urbs[i]);
-		for (i = 0; i < N_OUT_URB; i++)
-			usb_unlink_urb(portdata->out_urbs[i]);
 	}
 	port->tty = NULL;
 }
@@ -527,13 +534,6 @@ static void sierra_setup_urbs(struct usb_serial *serial)
                   	port->bulk_in_endpointAddress, USB_DIR_IN, port,
                   	portdata->in_buffer[j], IN_BUFLEN, sierra_indat_callback);
 		}
-
-		/* outdat endpoints */
-		for (j = 0; j < N_OUT_URB; ++j) {
-			portdata->out_urbs[j] = sierra_setup_urb (serial,
-                  	port->bulk_out_endpointAddress, USB_DIR_OUT, port,
-                  	portdata->out_buffer[j], OUT_BUFLEN, sierra_outdat_callback);
-		}
 	}
 }
 
@@ -552,8 +552,9 @@ static int sierra_startup(struct usb_serial *serial)
 		if (!portdata) {
 			dbg("%s: kmalloc for sierra_port_private (%d) failed!.",
 					__FUNCTION__, i);
-			return (1);
+			return -ENOMEM;
 		}
+		spin_lock_init(&portdata->lock);
 
 		usb_set_serial_port_data(port, portdata);
 
@@ -567,7 +568,7 @@ static int sierra_startup(struct usb_serial *serial)
 
 	sierra_setup_urbs(serial);
 
-	return (0);
+	return 0;
 }
 
 static void sierra_shutdown(struct usb_serial *serial)
@@ -589,8 +590,6 @@ static void sierra_shutdown(struct usb_serial *serial)
 
 		for (j = 0; j < N_IN_URB; j++)
 			usb_unlink_urb(portdata->in_urbs[j]);
-		for (j = 0; j < N_OUT_URB; j++)
-			usb_unlink_urb(portdata->out_urbs[j]);
 	}
 
 	/* Now free them */
@@ -608,12 +607,6 @@ static void sierra_shutdown(struct usb_serial *serial)
 				portdata->in_urbs[j] = NULL;
 			}
 		}
-		for (j = 0; j < N_OUT_URB; j++) {
-			if (portdata->out_urbs[j]) {
-				usb_free_urb(portdata->out_urbs[j]);
-				portdata->out_urbs[j] = NULL;
-			}
-		}
 	}
 
 	/* Now free per port private data */