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Commit 63832515 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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USB: serial: fix assumption that throttle/unthrottle cannot sleep 



many serial subdrivers are clearly written as if throttle/unthrottle
cannot sleep. This leads to unneeded atomic submissions. This
patch converts affected drivers in a way to makes very clear that
throttle/unthrottle can sleep. Thus future misdesigns can be avoided
and efficiency and reliability improved.

This removes any such assumption using GFP_KERNEL and spin_lock_irq()

Signed-off-by: default avatarOliver Neukum <oliver@neukum.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent b2a5cf1b

drivers/usb/serial/aircable.c

+4 −6
Original line number Diff line number Diff line
@@ -554,13 +554,12 @@ static void aircable_throttle(struct tty_struct *tty) 
{

	struct usb_serial_port *port = tty->driver_data;

	struct aircable_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;



	dbg("%s - port %d", __func__, port->number);



	spin_lock_irqsave(&priv->rx_lock, flags);

	spin_lock_irq(&priv->rx_lock);

	priv->rx_flags |= THROTTLED;

	spin_unlock_irqrestore(&priv->rx_lock, flags);

	spin_unlock_irq(&priv->rx_lock);

}



/* Based on ftdi_sio.c unthrottle */
@@ -569,14 +568,13 @@ static void aircable_unthrottle(struct tty_struct *tty) 
	struct usb_serial_port *port = tty->driver_data;

	struct aircable_private *priv = usb_get_serial_port_data(port);

	int actually_throttled;

	unsigned long flags;



	dbg("%s - port %d", __func__, port->number);



	spin_lock_irqsave(&priv->rx_lock, flags);

	spin_lock_irq(&priv->rx_lock);

	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;

	priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);

	spin_unlock_irqrestore(&priv->rx_lock, flags);

	spin_unlock_irq(&priv->rx_lock);



	if (actually_throttled)

		schedule_work(&priv->rx_work);

drivers/usb/serial/cypress_m8.c

+5 −7
Original line number Diff line number Diff line
@@ -1155,13 +1155,12 @@ static void cypress_throttle(struct tty_struct *tty) 
{

	struct usb_serial_port *port = tty->driver_data;

	struct cypress_private *priv = usb_get_serial_port_data(port);

	unsigned long flags;



	dbg("%s - port %d", __func__, port->number);



	spin_lock_irqsave(&priv->lock, flags);

	spin_lock_irq(&priv->lock);

	priv->rx_flags = THROTTLED;

	spin_unlock_irqrestore(&priv->lock, flags);

	spin_unlock_irq(&priv->lock);

}
@@ -1170,14 +1169,13 @@ static void cypress_unthrottle(struct tty_struct *tty) 
	struct usb_serial_port *port = tty->driver_data;

	struct cypress_private *priv = usb_get_serial_port_data(port);

	int actually_throttled, result;

	unsigned long flags;



	dbg("%s - port %d", __func__, port->number);



	spin_lock_irqsave(&priv->lock, flags);

	spin_lock_irq(&priv->lock);

	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;

	priv->rx_flags = 0;

	spin_unlock_irqrestore(&priv->lock, flags);

	spin_unlock_irq(&priv->lock);



	if (!priv->comm_is_ok)

		return;
@@ -1185,7 +1183,7 @@ static void cypress_unthrottle(struct tty_struct *tty) 
	if (actually_throttled) {

		port->interrupt_in_urb->dev = port->serial->dev;



		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);

		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);

		if (result) {

			dev_err(&port->dev, "%s - failed submitting read urb, "

					"error %d\n", __func__, result);

drivers/usb/serial/empeg.c

+1 −1
Original line number Diff line number Diff line
@@ -391,7 +391,7 @@ static void empeg_unthrottle(struct tty_struct *tty) 
	dbg("%s - port %d", __func__, port->number);



	port->read_urb->dev = port->serial->dev;

	result = usb_submit_urb(port->read_urb, GFP_ATOMIC);

	result = usb_submit_urb(port->read_urb, GFP_KERNEL);

	if (result)

		dev_err(&port->dev,

			"%s - failed submitting read urb, error %d\n",

drivers/usb/serial/garmin_gps.c

+5 −7
Original line number Diff line number Diff line
@@ -1390,14 +1390,13 @@ static void garmin_throttle(struct tty_struct *tty) 
{

	struct usb_serial_port *port = tty->driver_data;

	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);

	unsigned long flags;



	dbg("%s - port %d", __func__, port->number);

	/* set flag, data received will be put into a queue

	   for later processing */

	spin_lock_irqsave(&garmin_data_p->lock, flags);

	spin_lock_irq(&garmin_data_p->lock);

	garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;

	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	spin_unlock_irq(&garmin_data_p->lock);

}
@@ -1405,13 +1404,12 @@ static void garmin_unthrottle(struct tty_struct *tty) 
{

	struct usb_serial_port *port = tty->driver_data;

	struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);

	unsigned long flags;

	int status;



	dbg("%s - port %d", __func__, port->number);

	spin_lock_irqsave(&garmin_data_p->lock, flags);

	spin_lock_irq(&garmin_data_p->lock);

	garmin_data_p->flags &= ~FLAGS_THROTTLED;

	spin_unlock_irqrestore(&garmin_data_p->lock, flags);

	spin_unlock_irq(&garmin_data_p->lock);



	/* in native mode send queued data to tty, in

	   serial mode nothing needs to be done here */
@@ -1419,7 +1417,7 @@ static void garmin_unthrottle(struct tty_struct *tty) 
		garmin_flush_queue(garmin_data_p);



	if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {

		status = usb_submit_urb(port->read_urb, GFP_ATOMIC);

		status = usb_submit_urb(port->read_urb, GFP_KERNEL);

		if (status)

			dev_err(&port->dev,

				"%s - failed resubmitting read urb, error %d\n",

drivers/usb/serial/keyspan_pda.c

+1 −1
Original line number Diff line number Diff line
@@ -290,7 +290,7 @@ static void keyspan_pda_rx_unthrottle(struct tty_struct *tty) 
	/* just restart the receive interrupt URB */

	dbg("keyspan_pda_rx_unthrottle port %d", port->number);

	port->interrupt_in_urb->dev = port->serial->dev;

	if (usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC))

	if (usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL))

		dbg(" usb_submit_urb(read urb) failed");

	return;

}