ChangeSet 1.1002.3.15, 2003/02/25 11:16:10-08:00, [EMAIL PROTECTED]
USB: fixed potential races in belkin_sa.c now that there's no locks in the usb-serial
core
drivers/usb/serial/belkin_sa.c | 53 ++++++++++++++++++++++++++++++++---------
1 files changed, 42 insertions(+), 11 deletions(-)
diff -Nru a/drivers/usb/serial/belkin_sa.c b/drivers/usb/serial/belkin_sa.c
--- a/drivers/usb/serial/belkin_sa.c Fri Feb 28 14:50:25 2003
+++ b/drivers/usb/serial/belkin_sa.c Fri Feb 28 14:50:25 2003
@@ -144,6 +144,7 @@
struct belkin_sa_private {
+ spinlock_t lock;
unsigned long control_state;
unsigned char last_lsr;
unsigned char last_msr;
@@ -175,6 +176,7 @@
if (!priv)
return (-1); /* error */
/* set initial values for control structures */
+ spin_lock_init(&priv->lock);
priv->control_state = 0;
priv->last_lsr = 0;
priv->last_msr = 0;
@@ -262,6 +264,7 @@
struct usb_serial *serial;
unsigned char *data = urb->transfer_buffer;
int retval;
+ unsigned long flags;
switch (urb->status) {
case 0:
@@ -289,6 +292,7 @@
/* ignore data[0] and data[1] */
priv = usb_get_serial_port_data(port);
+ spin_lock_irqsave(&priv->lock, flags);
priv->last_msr = data[BELKIN_SA_MSR_INDEX];
/* Record Control Line states */
@@ -336,6 +340,7 @@
}
}
#endif
+ spin_unlock_irqrestore(&priv->lock, flags);
exit:
retval = usb_submit_urb (urb, GFP_ATOMIC);
if (retval)
@@ -352,6 +357,9 @@
unsigned int old_iflag = 0;
unsigned int old_cflag = 0;
__u16 urb_value = 0; /* Will hold the new flags */
+ unsigned long flags;
+ unsigned long control_state;
+ int bad_flow_control;
if ((!port->tty) || (!port->tty->termios)) {
dbg ("%s - no tty or termios structure", __FUNCTION__);
@@ -361,6 +369,12 @@
iflag = port->tty->termios->c_iflag;
cflag = port->tty->termios->c_cflag;
+ /* get a local copy of the current port settings */
+ spin_lock_irqsave(&priv->lock, flags);
+ control_state = priv->control_state;
+ bad_flow_control = priv->bad_flow_control;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
/* check that they really want us to change something */
if (old_termios) {
if ((cflag == old_termios->c_cflag) &&
@@ -376,7 +390,7 @@
if( (cflag&CBAUD) != (old_cflag&CBAUD) ) {
/* reassert DTR and (maybe) RTS on transition from B0 */
if( (old_cflag&CBAUD) == B0 ) {
- priv->control_state |= (TIOCM_DTR|TIOCM_RTS);
+ control_state |= (TIOCM_DTR|TIOCM_RTS);
if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 1) < 0)
err("Set DTR error");
/* don't set RTS if using hardware flow control */
@@ -410,7 +424,7 @@
err("Disable flowcontrol error");
/* Drop RTS and DTR */
- priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
+ control_state &= ~(TIOCM_DTR | TIOCM_RTS);
if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 0) < 0)
err("DTR LOW error");
if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, 0) < 0)
@@ -465,12 +479,17 @@
else
urb_value &= ~(BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS);
- if (priv->bad_flow_control)
+ if (bad_flow_control)
urb_value &= ~(BELKIN_SA_FLOW_IRTS);
if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST, urb_value) < 0)
err("Set flow control error");
}
+
+ /* save off the modified port settings */
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->control_state = control_state;
+ spin_unlock_irqrestore(&priv->lock, flags);
} /* belkin_sa_set_termios */
@@ -488,12 +507,19 @@
struct usb_serial *serial = port->serial;
__u16 urb_value; /* Will hold the new flags */
struct belkin_sa_private *priv = usb_get_serial_port_data(port);
- int ret, mask;
+ int ret = 0;
+ int mask;
+ unsigned long control_state;
+ unsigned long flags;
+ spin_lock_irqsave(&priv->lock, flags);
+ control_state = priv->control_state;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
/* Based on code from acm.c and others */
switch (cmd) {
case TIOCMGET:
- return put_user(priv->control_state, (unsigned long *) arg);
+ return put_user(control_state, (unsigned long *) arg);
break;
case TIOCMSET: /* Turns on and off the lines as specified by the mask */
@@ -506,13 +532,13 @@
/* RTS needs set */
urb_value = ((cmd == TIOCMSET) && (mask & TIOCM_RTS)) || (cmd
== TIOCMBIS) ? 1 : 0;
if (urb_value)
- priv->control_state |= TIOCM_RTS;
+ control_state |= TIOCM_RTS;
else
- priv->control_state &= ~TIOCM_RTS;
+ control_state &= ~TIOCM_RTS;
if ((ret = BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, urb_value))
< 0) {
err("Set RTS error %d", ret);
- return(ret);
+ goto cmerror;
}
}
@@ -520,14 +546,19 @@
/* DTR needs set */
urb_value = ((cmd == TIOCMSET) && (mask & TIOCM_DTR)) || (cmd
== TIOCMBIS) ? 1 : 0;
if (urb_value)
- priv->control_state |= TIOCM_DTR;
+ control_state |= TIOCM_DTR;
else
- priv->control_state &= ~TIOCM_DTR;
+ control_state &= ~TIOCM_DTR;
if ((ret = BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, urb_value))
< 0) {
err("Set DTR error %d", ret);
- return(ret);
+ goto cmerror;
}
}
+cmerror:
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->control_state = control_state;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return ret;
break;
case TIOCMIWAIT:
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