Commit 9c922a90 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: usbduxsigma: set *_cmd_running flags before submitting urbs 



As pointed out by Ian Abbott, the *_cmd_running flags should be set
before submitting the urbs. There is a possible race condition where
an urb could complete and the flag is checked in the completion
routine before it's set.

Reported-by: default avatarIan Abbott <abbotti@mev.co.uk>
Acked-by: default avatarIan Abbott <abbotti@mev.co.uk>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b07dee7c

drivers/staging/comedi/drivers/usbduxsigma.c

+12 −6
Original line number Diff line number Diff line
@@ -686,13 +686,14 @@ static int usbduxsigma_ai_inttrig(struct comedi_device *dev, 


	down(&devpriv->sem);

	if (!devpriv->ai_cmd_running) {

		devpriv->ai_cmd_running = 1;

		ret = usbduxsigma_submit_urbs(dev, devpriv->ai_urbs,

					      devpriv->n_ai_urbs, 1);

		if (ret < 0) {

			devpriv->ai_cmd_running = 0;

			up(&devpriv->sem);

			return ret;

		}

		devpriv->ai_cmd_running = 1;

		s->async->inttrig = NULL;

	}

	up(&devpriv->sem);
@@ -740,14 +741,15 @@ static int usbduxsigma_ai_cmd(struct comedi_device *dev, 


	if (cmd->start_src == TRIG_NOW) {

		/* enable this acquisition operation */

		devpriv->ai_cmd_running = 1;

		ret = usbduxsigma_submit_urbs(dev, devpriv->ai_urbs,

					      devpriv->n_ai_urbs, 1);

		if (ret < 0) {

			devpriv->ai_cmd_running = 0;

			up(&devpriv->sem);

			return ret;

		}

		s->async->inttrig = NULL;

		devpriv->ai_cmd_running = 1;

	} else {	/* TRIG_INT */

		/* wait for an internal signal and submit the urbs later */

		s->async->inttrig = usbduxsigma_ai_inttrig;
@@ -876,13 +878,14 @@ static int usbduxsigma_ao_inttrig(struct comedi_device *dev, 


	down(&devpriv->sem);

	if (!devpriv->ao_cmd_running) {

		devpriv->ao_cmd_running = 1;

		ret = usbduxsigma_submit_urbs(dev, devpriv->ao_urbs,

					      devpriv->n_ao_urbs, 0);

		if (ret < 0) {

			devpriv->ao_cmd_running = 0;

			up(&devpriv->sem);

			return ret;

		}

		devpriv->ao_cmd_running = 1;

		s->async->inttrig = NULL;

	}

	up(&devpriv->sem);
@@ -1026,14 +1029,15 @@ static int usbduxsigma_ao_cmd(struct comedi_device *dev, 


	if (cmd->start_src == TRIG_NOW) {

		/* enable this acquisition operation */

		devpriv->ao_cmd_running = 1;

		ret = usbduxsigma_submit_urbs(dev, devpriv->ao_urbs,

					      devpriv->n_ao_urbs, 0);

		if (ret < 0) {

			devpriv->ao_cmd_running = 0;

			up(&devpriv->sem);

			return ret;

		}

		s->async->inttrig = NULL;

		devpriv->ao_cmd_running = 1;

	} else {	/* TRIG_INT */

		/* wait for an internal signal and submit the urbs later */

		s->async->inttrig = usbduxsigma_ao_inttrig;
@@ -1237,10 +1241,12 @@ static int usbduxsigma_pwm_start(struct comedi_device *dev, 


	memset(devpriv->pwm_urb->transfer_buffer, 0, devpriv->pwm_buf_sz);



	devpriv->pwm_cmd_running = 1;

	ret = usbduxsigma_submit_pwm_urb(dev);

	if (ret < 0)

	if (ret < 0) {

		devpriv->pwm_cmd_running = 0;

		return ret;

	devpriv->pwm_cmd_running = 1;

	}



	return 0;

}