Grab disconnect mutex in chars_in_buffer before checking disconnected
flag or calling driver specific function.
This allows subdrivers to query any hardware buffer status without
having to handle the locking themselves.
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
---
drivers/usb/serial/usb-serial.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 64bda13..0a17f59 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -361,15 +361,21 @@ static int serial_write_room(struct tty_struct *tty)
static int serial_chars_in_buffer(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
+ struct usb_serial *serial = port->serial;
+ int count = 0;
dev_dbg(tty->dev, "%s - port %d\n", __func__, port->number);
+ mutex_lock(&serial->disc_mutex);
/* if the device was unplugged then any remaining characters
fell out of the connector ;) */
- if (port->serial->disconnected)
- return 0;
- /* pass on to the driver specific version of this function */
- return port->serial->type->chars_in_buffer(tty);
+ if (serial->disconnected)
+ count = 0;
+ else
+ count = serial->type->chars_in_buffer(tty);
+ mutex_unlock(&serial->disc_mutex);
+
+ return count;
}
static void serial_throttle(struct tty_struct *tty)
--
1.8.1
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