From 9c67d28e4e7683b4f667fa4c7b6f9aee92b44b5c Mon Sep 17 00:00:00 2001
From: Alessio Igor Bogani <abogani@texware.it>
Date: Sat, 13 Mar 2010 18:35:14 +0100
Subject: [PATCH] USB: ftdi_sio: Fix locking for change_speed() function
The change_speed() function should be serialized against multiple calls.
Use the cfg_lock mutex to do this.
Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/usb/serial/ftdi_sio.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 6fc09dc3b53e..1d7c4fac02e8 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -91,7 +91,7 @@ struct ftdi_private {
unsigned long tx_outstanding_bytes;
unsigned long tx_outstanding_urbs;
unsigned short max_packet_size;
- struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl() */
+ struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl() and change_speed() */
};
/* struct ftdi_sio_quirk is used by devices requiring special attention. */
@@ -1273,8 +1273,8 @@ static int set_serial_info(struct tty_struct *tty,
(priv->flags & ASYNC_SPD_MASK)) ||
(((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&
(old_priv.custom_divisor != priv->custom_divisor))) {
- mutex_unlock(&priv->cfg_lock);
change_speed(tty, port);
+ mutex_unlock(&priv->cfg_lock);
}
else
mutex_unlock(&priv->cfg_lock);
@@ -2265,9 +2265,11 @@ static void ftdi_set_termios(struct tty_struct *tty,
clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
} else {
/* set the baudrate determined before */
+ mutex_lock(&priv->cfg_lock);
if (change_speed(tty, port))
dev_err(&port->dev, "%s urb failed to set baudrate\n",
__func__);
+ mutex_unlock(&priv->cfg_lock);
/* Ensure RTS and DTR are raised when baudrate changed from 0 */
if (!old_termios || (old_termios->c_cflag & CBAUD) == B0)
set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
--
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