[PATCH 08/49] staging: comedi: cb_pcidas: factor out step 5 of (*do_cmdtest)
Ian Abbott
abbotti at mev.co.uk
Wed Apr 16 16:34:55 UTC 2014
On 2014-04-15 18:37, H Hartley Sweeten wrote:
> Step 5 of the (*do_cmdtest) validates that the chanlist, chan/range/aref/etc,
> is compatible with the actual hardware. At this point in the (*do_cmdtest)
> the chanlist is valid, due to checks in the core, so the sanity check is not
> needed.
>
> For aesthetics, factor the step 5 code into a helper functions. Tidy up the
> factored out code.
>
> 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/cb_pcidas.c | 77 +++++++++++++++++++-----------
> 1 file changed, 49 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/cb_pcidas.c b/drivers/staging/comedi/drivers/cb_pcidas.c
> index 83a265f..d01cf9a 100644
> --- a/drivers/staging/comedi/drivers/cb_pcidas.c
> +++ b/drivers/staging/comedi/drivers/cb_pcidas.c
> @@ -803,6 +803,32 @@ static int trimpot_read_insn(struct comedi_device *dev,
> return 1;
> }
>
> +static int cb_pcidas_ai_check_chanlist(struct comedi_device *dev,
> + struct comedi_subdevice *s,
> + struct comedi_cmd *cmd)
> +{
> + unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
> + unsigned int range0 = CR_RANGE(cmd->chanlist[0]);
> + int i;
> +
> + for (i = 1; i < cmd->chanlist_len; i++) {
> + unsigned int chan = CR_CHAN(cmd->chanlist[i]);
> + unsigned int range = CR_RANGE(cmd->chanlist[i]);
> +
> + if (chan != (chan0 + i) % s->n_chan) {
> + dev_err(dev->class_dev,
> + "chanlist must be consecutive channels, counting upwards\n");
> + return -EINVAL;
> + }
> + if (range != range0) {
> + dev_err(dev->class_dev,
> + "chanlist must all have the same range\n");
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> static int cb_pcidas_ai_cmdtest(struct comedi_device *dev,
> struct comedi_subdevice *s,
> struct comedi_cmd *cmd)
> @@ -811,7 +837,6 @@ static int cb_pcidas_ai_cmdtest(struct comedi_device *dev,
> struct cb_pcidas_private *devpriv = dev->private;
> int err = 0;
> int tmp;
> - int i, gain, start_chan;
>
> /* Step 1 : check if triggers are trivially valid */
>
> @@ -907,24 +932,9 @@ static int cb_pcidas_ai_cmdtest(struct comedi_device *dev,
> if (err)
> return 4;
>
> - /* check channel/gain list against card's limitations */
> - if (cmd->chanlist) {
> - gain = CR_RANGE(cmd->chanlist[0]);
> - start_chan = CR_CHAN(cmd->chanlist[0]);
> - for (i = 1; i < cmd->chanlist_len; i++) {
> - if (CR_CHAN(cmd->chanlist[i]) !=
> - (start_chan + i) % s->n_chan) {
> - comedi_error(dev,
> - "entries in chanlist must be consecutive channels, counting upwards\n");
> - err++;
> - }
> - if (CR_RANGE(cmd->chanlist[i]) != gain) {
> - comedi_error(dev,
> - "entries in chanlist must all have the same gain\n");
> - err++;
> - }
> - }
> - }
> + /* Step 5: check channel list */
> +
> + err |= cb_pcidas_ai_check_chanlist(dev, s, cmd);
>
> if (err)
> return 5;
> @@ -1035,6 +1045,23 @@ static int cb_pcidas_ai_cmd(struct comedi_device *dev,
> return 0;
> }
As for the remarks in patch 02, it's possible for chanlist to be NULL or
for chanlist_len to be 0, so cb_pcidas_ai_check_chanlist() should only
be called if chanlist is non-NULL and chanlist_len is non-0.
But if chanlist is forced to be NULL by __comedi_get_user_chanlist()
when chanlist_len is 0, it would be sufficient to check that chanlist is
non-NULL before calling cb_pcidas_ai_check_chanlist().
The original code is buggy as well because it accesses cmd->chanlist[0]
without checking cmd->chanlist_len.
>
> +static int cb_pcidas_ao_check_chanlist(struct comedi_device *dev,
> + struct comedi_subdevice *s,
> + struct comedi_cmd *cmd)
> +{
> + if (cmd->chanlist_len > 1) {
> + unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
> + unsigned int chan1 = CR_CHAN(cmd->chanlist[1]);
> +
> + if (chan0 != 0 || chan1 != 1) {
> + dev_err(dev->class_dev,
> + "channels must be ordered channel 0, channel 1 in chanlist\n");
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> static int cb_pcidas_ao_cmdtest(struct comedi_device *dev,
> struct comedi_subdevice *s,
> struct comedi_cmd *cmd)
> @@ -1097,15 +1124,9 @@ static int cb_pcidas_ao_cmdtest(struct comedi_device *dev,
> if (err)
> return 4;
>
> - /* check channel/gain list against card's limitations */
> - if (cmd->chanlist && cmd->chanlist_len > 1) {
> - if (CR_CHAN(cmd->chanlist[0]) != 0 ||
> - CR_CHAN(cmd->chanlist[1]) != 1) {
> - comedi_error(dev,
> - "channels must be ordered channel 0, channel 1 in chanlist\n");
> - err++;
> - }
> - }
> + /* Step 5: check channel list */
> +
> + err |= cb_pcidas_ao_check_chanlist(dev, s, cmd);
>
> if (err)
> return 5;
>
Ditto for calling cb_pcidas_ao_check_chanlist().
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti at mev.co.uk> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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