From b2a5cf1bdc011f5474c72543f9d8116c0f07f452 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 7 Oct 2009 09:30:49 +0200 Subject: USB: serial: fix race between unthrottle and completion handler in symbolserial usb:usbserial:symbolserial: fix race between unthrottle and completion handler symbol_unthrottle() mustn't resubmit the URB unconditionally as the URB may still be running. the same bug as opticon. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/symbolserial.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'drivers/usb/serial/symbolserial.c') diff --git a/drivers/usb/serial/symbolserial.c b/drivers/usb/serial/symbolserial.c index cb7e95f9fcbf..f25e54526843 100644 --- a/drivers/usb/serial/symbolserial.c +++ b/drivers/usb/serial/symbolserial.c @@ -179,20 +179,24 @@ static void symbol_unthrottle(struct tty_struct *tty) 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); priv->throttled = false; + was_throttled = priv->actually_throttled; priv->actually_throttled = false; spin_unlock_irqrestore(&priv->lock, flags); priv->int_urb->dev = port->serial->dev; - result = usb_submit_urb(priv->int_urb, GFP_ATOMIC); - if (result) - dev_err(&port->dev, - "%s - failed submitting read urb, error %d\n", + if (was_throttled) { + result = usb_submit_urb(priv->int_urb, GFP_ATOMIC); + if (result) + dev_err(&port->dev, + "%s - failed submitting read urb, error %d\n", __func__, result); + } } static int symbol_startup(struct usb_serial *serial) -- cgit v1.2.2 From 638325154572ba2113a18669fe3b299caa2dabd9 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 7 Oct 2009 10:50:23 +0200 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/symbolserial.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'drivers/usb/serial/symbolserial.c') diff --git a/drivers/usb/serial/symbolserial.c b/drivers/usb/serial/symbolserial.c index f25e54526843..b282c0f2d8e5 100644 --- a/drivers/usb/serial/symbolserial.c +++ b/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", -- cgit v1.2.2