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>
diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
index ad4998b..cd009cb 100644
--- a/drivers/usb/serial/mct_u232.c
+++ b/drivers/usb/serial/mct_u232.c
@@ -777,20 +777,19 @@
{
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 @@
{
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);
}
}