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/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index e0a8b71..a591ebe 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -1155,13 +1155,12 @@
{
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 @@
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 @@
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);