[PATCH 49/51] staging: comedi: ni_pcidio: request_irq() before seting up subdevices

[Ian Abbott]

On 2013-12-03 19:07, H Hartley Sweeten wrote:
> Do the request_irq() before setting up the subdevices. Only hook up
> the command support of the irq was sucessfully requested.
>
> Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
> Cc: Ian Abbott <abbotti at mev.co.uk>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> ---
>   drivers/staging/comedi/drivers/ni_pcidio.c | 38 +++++++++++++++---------------
>   1 file changed, 19 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/ni_pcidio.c b/drivers/staging/comedi/drivers/ni_pcidio.c
> index 9c2bd6c..281665d 100644
> --- a/drivers/staging/comedi/drivers/ni_pcidio.c
> +++ b/drivers/staging/comedi/drivers/ni_pcidio.c
> @@ -1011,6 +1011,14 @@ static int nidio_auto_attach(struct comedi_device *dev,
>
>   	nidio_reset_board(dev);
>
> +	irq = mite_irq(devpriv->mite);
> +	if (irq) {
> +		ret = request_irq(irq, nidio_interrupt, IRQF_SHARED,
> +				  dev->board_name, dev);
> +		if (ret == 0)
> +			dev->irq = irq;
> +	}
> +

This results in  a couple of NULL dereferences in nidio_interrupt():

	struct comedi_subdevice *s = &dev->subdevices[0];
	struct comedi_async *async = s->async;

The first one would be fixed by your PATCH 50/51, but the other one isn't.

The easiest fix would be to request the IRQ after allocating the subdevices.

>   	ret = comedi_alloc_subdevices(dev, 1);
>   	if (ret)
>   		return ret;
> @@ -1019,31 +1027,23 @@ static int nidio_auto_attach(struct comedi_device *dev,
>   		 readb(devpriv->mite->daq_io_addr + Chip_Version));
>
>   	s = &dev->subdevices[0];
> -
> -	dev->read_subdev = s;
>   	s->type = COMEDI_SUBD_DIO;
> -	s->subdev_flags =
> -		SDF_READABLE | SDF_WRITABLE | SDF_LSAMPL | SDF_PACKED |
> -		SDF_CMD_READ;
> +	s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_LSAMPL | SDF_PACKED;
>   	s->n_chan = 32;
>   	s->range_table = &range_digital;
>   	s->maxdata = 1;
>   	s->insn_config = &ni_pcidio_insn_config;
>   	s->insn_bits = &ni_pcidio_insn_bits;
> -	s->do_cmd = &ni_pcidio_cmd;
> -	s->do_cmdtest = &ni_pcidio_cmdtest;
> -	s->cancel = &ni_pcidio_cancel;
> -	s->len_chanlist = 32;	/* XXX */
> -	s->buf_change = &ni_pcidio_change;
> -	s->async_dma_dir = DMA_BIDIRECTIONAL;
> -	s->poll = &ni_pcidio_poll;
> -
> -	irq = mite_irq(devpriv->mite);
> -	if (irq) {
> -		ret = request_irq(irq, nidio_interrupt, IRQF_SHARED,
> -				  dev->board_name, dev);
> -		if (ret == 0)
> -			dev->irq = irq;
> +	if (dev->irq) {
> +		dev->read_subdev = s;
> +		s->subdev_flags |= SDF_CMD_READ;
> +		s->async_dma_dir = DMA_BIDIRECTIONAL;
> +		s->len_chanlist = s->n_chan;
> +		s->do_cmd = ni_pcidio_cmd;
> +		s->do_cmdtest = ni_pcidio_cmdtest;
> +		s->cancel = ni_pcidio_cancel;
> +		s->poll = ni_pcidio_poll;
> +		s->buf_change = ni_pcidio_change;
>   	}
>
>   	return 0;
>


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