staging: comedi: usbduxsigma: change return type of the stop functions

The usbdux_pwm_cancel() function is the only caller that does not validate
the comedi_device private data before calling the stop function. Move the
validation test to that function and remove the unnecessary sanity checks.

Since the stop functions always succeed, change the return type to void.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/usbduxsigma.c

@@ -262,17 +262,12 @@ static void usbduxsub_unlink_InURBs(struct usbduxsub *devpriv)
 	}
 }
 
-static int usbdux_ai_stop(struct usbduxsub *devpriv, int do_unlink)
+static void usbdux_ai_stop(struct usbduxsub *devpriv, int do_unlink)
 {
-	if (!devpriv)
-		return -EFAULT;
-
 	if (do_unlink)
 		usbduxsub_unlink_InURBs(devpriv);
 
 	devpriv->ai_cmd_running = 0;
-
-	return 0;
 }
 
 /*
@@ -283,7 +278,6 @@ static int usbdux_ai_cancel(struct comedi_device *dev,
 			    struct comedi_subdevice *s)
 {
 	struct usbduxsub *this_usbduxsub;
-	int res = 0;
 
 	/* force unlink of all urbs */
 	this_usbduxsub = dev->private;
@@ -297,9 +291,10 @@ static int usbdux_ai_cancel(struct comedi_device *dev,
 		return -ENODEV;
 	}
 	/* unlink only if the urb really has been submitted */
-	res = usbdux_ai_stop(this_usbduxsub, this_usbduxsub->ai_cmd_running);
+	usbdux_ai_stop(this_usbduxsub, this_usbduxsub->ai_cmd_running);
 	up(&this_usbduxsub->sem);
-	return res;
+
+	return 0;
 }
 
 /* analogue IN - interrupt service routine */
@@ -457,17 +452,12 @@ static void usbduxsub_unlink_OutURBs(struct usbduxsub *devpriv)
 	}
 }
 
-static int usbdux_ao_stop(struct usbduxsub *devpriv, int do_unlink)
+static void usbdux_ao_stop(struct usbduxsub *devpriv, int do_unlink)
 {
-	if (!devpriv)
-		return -EFAULT;
-
 	if (do_unlink)
 		usbduxsub_unlink_OutURBs(devpriv);
 
 	devpriv->ao_cmd_running = 0;
-
-	return 0;
 }
 
 /* force unlink, is called by comedi */
@@ -475,7 +465,6 @@ static int usbdux_ao_cancel(struct comedi_device *dev,
 			    struct comedi_subdevice *s)
 {
 	struct usbduxsub *this_usbduxsub = dev->private;
-	int res = 0;
 
 	if (!this_usbduxsub)
 		return -EFAULT;
@@ -487,9 +476,10 @@ static int usbdux_ao_cancel(struct comedi_device *dev,
 		return -ENODEV;
 	}
 	/* unlink only if it is really running */
-	res = usbdux_ao_stop(this_usbduxsub, this_usbduxsub->ao_cmd_running);
+	usbdux_ao_stop(this_usbduxsub, this_usbduxsub->ao_cmd_running);
 	up(&this_usbduxsub->sem);
-	return res;
+
+	return 0;
 }
 
 static void usbduxsub_ao_IsocIrq(struct urb *urb)
@@ -1637,17 +1627,12 @@ static void usbduxsub_unlink_PwmURBs(struct usbduxsub *devpriv)
 		usb_kill_urb(devpriv->urbPwm);
 }
 
-static int usbdux_pwm_stop(struct usbduxsub *devpriv, int do_unlink)
+static void usbdux_pwm_stop(struct usbduxsub *devpriv, int do_unlink)
 {
-	if (!devpriv)
-		return -EFAULT;
-
 	if (do_unlink)
 		usbduxsub_unlink_PwmURBs(devpriv);
 
 	devpriv->pwm_cmd_running = 0;
-
-	return 0;
 }
 
 /* force unlink - is called by comedi */
@@ -1655,16 +1640,14 @@ static int usbdux_pwm_cancel(struct comedi_device *dev,
 			     struct comedi_subdevice *s)
 {
 	struct usbduxsub *this_usbduxsub = dev->private;
-	int res = 0;
 
-	/* unlink only if it is really running */
-	res = usbdux_pwm_stop(this_usbduxsub, this_usbduxsub->pwm_cmd_running);
+	if (!this_usbduxsub)
+		return -EFAULT;
 
-	res = send_dux_commands(this_usbduxsub, SENDPWMOFF);
-	if (res < 0)
-		return res;
+	/* unlink only if it is really running */
+	usbdux_pwm_stop(this_usbduxsub, this_usbduxsub->pwm_cmd_running);
 
-	return res;
+	return send_dux_commands(this_usbduxsub, SENDPWMOFF);
 }
 
 static void usbduxsub_pwm_irq(struct urb *urb)