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USB: serial: fix assumption that throttle/unthrottle cannot sleep

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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>
This commit is contained in:
Oliver Neukum
2009-10-07 10:50:23 +02:00
committed by Greg Kroah-Hartman
parent b2a5cf1bdc
commit 6383251545
10 changed files with 37 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/usb/serial/mct_u232.c
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@ -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);
}
}