From dcbc0ae4f8fcdd4c873e7a9bac49ab84b0453813 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 19 May 2021 11:20:02 +0200 Subject: [PATCH] USB: serial: digi_acceleport: add chars_in_buffer locking Both the dp_write_urb_in_use flag and dp_out_buf_len counter should be accessed while holding the driver port lock. Add the missing locking to chars_in_buffer and clean up the implementation somewhat by using a common exit path. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold --- drivers/usb/serial/digi_acceleport.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c index a4194b70a6fe..754c66ff0fc1 100644 --- a/drivers/usb/serial/digi_acceleport.c +++ b/drivers/usb/serial/digi_acceleport.c @@ -1044,17 +1044,19 @@ static unsigned int digi_chars_in_buffer(struct tty_struct *tty) { struct usb_serial_port *port = tty->driver_data; struct digi_port *priv = usb_get_serial_port_data(port); + unsigned long flags; + unsigned int chars; - if (priv->dp_write_urb_in_use) { - dev_dbg(&port->dev, "digi_chars_in_buffer: port=%d, chars=%d\n", - priv->dp_port_num, port->bulk_out_size - 2); - return port->bulk_out_size - 2; - } else { - dev_dbg(&port->dev, "digi_chars_in_buffer: port=%d, chars=%d\n", - priv->dp_port_num, priv->dp_out_buf_len); - return priv->dp_out_buf_len; - } + spin_lock_irqsave(&priv->dp_port_lock, flags); + if (priv->dp_write_urb_in_use) + chars = port->bulk_out_size - 2; + else + chars = priv->dp_out_buf_len; + spin_unlock_irqrestore(&priv->dp_port_lock, flags); + dev_dbg(&port->dev, "%s: port=%d, chars=%d\n", __func__, + priv->dp_port_num, chars); + return chars; } static void digi_dtr_rts(struct usb_serial_port *port, int on)