[PATCH 39/53] staging: comedi: usbdux: tidy up usbdux_ao_inttrig()

[Ian Abbott]

On 2013-07-24 22:21, H Hartley Sweeten wrote:
> Rename the local variable used for the private data pointer to the
> comedi "norm".
>
> Remove the unnecessary sanity check of the private data pointer. This
> function can only be called is the private data was allocated during
> the attach.
>
> Tidy up the exit path using goto to ensure that the semaphore it
> released.
>
> Set the ao_cmd_running flag after submitting the urbs to remove the
> need to clear the flag if the submit fails.

As for AI, the URB completion handler usbduxsub_ao_isoc_irq() could 
execute before you set ao_cmd_running.

>
> Return -EBUSY if an ao command is already running.
>
> Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
> Cc: Ian Abbott <abbotti at mev.co.uk>
> Cc: Greg Kroah-Hartman <gregkh at linuxfondation.org>
> ---
>   drivers/staging/comedi/drivers/usbdux.c | 38 ++++++++++++++++-----------------
>   1 file changed, 19 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c
> index 3898aea..9efd125 100644
> --- a/drivers/staging/comedi/drivers/usbdux.c
> +++ b/drivers/staging/comedi/drivers/usbdux.c
> @@ -1072,31 +1072,31 @@ ao_write_exit:
>   }
>
>   static int usbdux_ao_inttrig(struct comedi_device *dev,
> -			     struct comedi_subdevice *s, unsigned int trignum)
> +			     struct comedi_subdevice *s,
> +			     unsigned int trignum)
>   {
> -	int ret;
> -	struct usbdux_private *this_usbduxsub = dev->private;
> +	struct usbdux_private *devpriv = dev->private;
> +	int ret = -EINVAL;
>
> -	if (!this_usbduxsub)
> -		return -EFAULT;
> +	down(&devpriv->sem);
>
> -	down(&this_usbduxsub->sem);
> -	if (trignum != 0) {
> -		up(&this_usbduxsub->sem);
> -		return -EINVAL;
> -	}
> -	if (!(this_usbduxsub->ao_cmd_running)) {
> -		this_usbduxsub->ao_cmd_running = 1;
> +	if (trignum != 0)
> +		goto ao_trig_exit;
> +
> +	if (!devpriv->ao_cmd_running) {
>   		ret = usbduxsub_submit_outurbs(dev);
> -		if (ret < 0) {
> -			this_usbduxsub->ao_cmd_running = 0;
> -			up(&this_usbduxsub->sem);
> -			return ret;
> -		}
> +		if (ret < 0)
> +			goto ao_trig_exit;
> +
> +		devpriv->ao_cmd_running = 1;
>   		s->async->inttrig = NULL;
> +	} else {
> +		ret = -EBUSY;
>   	}
> -	up(&this_usbduxsub->sem);
> -	return 1;
> +
> +ao_trig_exit:
> +	up(&devpriv->sem);
> +	return ret;
>   }
>
>   static int usbdux_ao_cmdtest(struct comedi_device *dev,
>


-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti at mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-