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: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/aircable.c

@@ -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

@@ -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

@@ -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

@@ -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

@@ -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;
 }

drivers/usb/serial/kl5kusb105.c

@@ -951,7 +951,7 @@ static void klsi_105_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/mct_u232.c

@@ -777,20 +777,19 @@ static void mct_u232_throttle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
-	unsigned long flags;
 	unsigned int control_state;
 
 	dbg("%s - port %d", __func__, port->number);
 
-	spin_lock_irqsave(&priv->lock, flags);
+	spin_lock_irq(&priv->lock);
 	priv->rx_flags |= THROTTLED;
 	if (C_CRTSCTS(tty)) {
 		priv->control_state &= ~TIOCM_RTS;
 		control_state = priv->control_state;
-		spin_unlock_irqrestore(&priv->lock, flags);
+		spin_unlock_irq(&priv->lock);
 		(void) mct_u232_set_modem_ctrl(port->serial, control_state);
 	} else {
-		spin_unlock_irqrestore(&priv->lock, flags);
+		spin_unlock_irq(&priv->lock);
 	}
 }
 
@@ -799,20 +798,19 @@ static void mct_u232_unthrottle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
-	unsigned long flags;
 	unsigned int control_state;
 
 	dbg("%s - port %d", __func__, port->number);
 
-	spin_lock_irqsave(&priv->lock, flags);
+	spin_lock_irq(&priv->lock);
 	if ((priv->rx_flags & THROTTLED) && C_CRTSCTS(tty)) {
 		priv->rx_flags &= ~THROTTLED;
 		priv->control_state |= TIOCM_RTS;
 		control_state = priv->control_state;
-		spin_unlock_irqrestore(&priv->lock, flags);
+		spin_unlock_irq(&priv->lock);
 		(void) mct_u232_set_modem_ctrl(port->serial, control_state);
 	} else {
-		spin_unlock_irqrestore(&priv->lock, flags);
+		spin_unlock_irq(&priv->lock);
 	}
 }
 

drivers/usb/serial/symbolserial.c

@@ -165,33 +165,31 @@ static void symbol_throttle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct symbol_private *priv = usb_get_serial_data(port->serial);
-	unsigned long flags;
 
 	dbg("%s - port %d", __func__, port->number);
-	spin_lock_irqsave(&priv->lock, flags);
+	spin_lock_irq(&priv->lock);
 	priv->throttled = true;
-	spin_unlock_irqrestore(&priv->lock, flags);
+	spin_unlock_irq(&priv->lock);
 }
 
 static void symbol_unthrottle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct symbol_private *priv = usb_get_serial_data(port->serial);
-	unsigned long flags;
 	int result;
 	bool was_throttled;
 
 	dbg("%s - port %d", __func__, port->number);
 
-	spin_lock_irqsave(&priv->lock, flags);
+	spin_lock_irq(&priv->lock);
 	priv->throttled = false;
 	was_throttled = priv->actually_throttled;
 	priv->actually_throttled = false;
-	spin_unlock_irqrestore(&priv->lock, flags);
+	spin_unlock_irq(&priv->lock);
 
 	priv->int_urb->dev = port->serial->dev;
 	if (was_throttled) {
-		result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
+		result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
 		if (result)
 			dev_err(&port->dev,
 				"%s - failed submitting read urb, error %d\n",

drivers/usb/serial/visor.c

@@ -583,12 +583,11 @@ static void visor_throttle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct visor_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->throttled = 1;
-	spin_unlock_irqrestore(&priv->lock, flags);
+	spin_unlock_irq(&priv->lock);
 }
 
 
@@ -596,17 +595,16 @@ static void visor_unthrottle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct visor_private *priv = usb_get_serial_port_data(port);
-	unsigned long flags;
 	int result;
 
 	dbg("%s - port %d", __func__, port->number);
-	spin_lock_irqsave(&priv->lock, flags);
+	spin_lock_irq(&priv->lock);
 	priv->throttled = 0;
 	priv->actually_throttled = 0;
-	spin_unlock_irqrestore(&priv->lock, flags);
+	spin_unlock_irq(&priv->lock);
 
 	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/whiteheat.c

@@ -949,13 +949,12 @@ static void whiteheat_throttle(struct tty_struct *tty)
 {
 	struct usb_serial_port *port = tty->driver_data;
 	struct whiteheat_private *info = usb_get_serial_port_data(port);
-	unsigned long flags;
 
 	dbg("%s - port %d", __func__, port->number);
 
-	spin_lock_irqsave(&info->lock, flags);
+	spin_lock_irq(&info->lock);
 	info->flags |= THROTTLED;
-	spin_unlock_irqrestore(&info->lock, flags);
+	spin_unlock_irq(&info->lock);
 
 	return;
 }
@@ -966,14 +965,13 @@ static void whiteheat_unthrottle(struct tty_struct *tty)
 	struct usb_serial_port *port = tty->driver_data;
 	struct whiteheat_private *info = usb_get_serial_port_data(port);
 	int actually_throttled;
-	unsigned long flags;
 
 	dbg("%s - port %d", __func__, port->number);
 
-	spin_lock_irqsave(&info->lock, flags);
+	spin_lock_irq(&info->lock);
 	actually_throttled = info->flags & ACTUALLY_THROTTLED;
 	info->flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
-	spin_unlock_irqrestore(&info->lock, flags);
+	spin_unlock_irq(&info->lock);
 
 	if (actually_throttled)
 		rx_data_softint(&info->rx_work);