[PATCH 09/49] staging: comedi: cb_pcidas64: factor out step 5 of (*do_cmdtest)
Ian Abbott
abbotti at mev.co.uk
Wed Apr 16 16:37:12 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_pcidas64.c | 106 ++++++++++++++++-----------
> 1 file changed, 62 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/cb_pcidas64.c b/drivers/staging/comedi/drivers/cb_pcidas64.c
> index 032bafe..a0756c5 100644
> --- a/drivers/staging/comedi/drivers/cb_pcidas64.c
> +++ b/drivers/staging/comedi/drivers/cb_pcidas64.c
> @@ -1995,14 +1995,49 @@ static void check_adc_timing(struct comedi_device *dev, struct comedi_cmd *cmd)
> return;
> }
>
> +static int cb_pcidas64_ai_check_chanlist(struct comedi_device *dev,
> + struct comedi_subdevice *s,
> + struct comedi_cmd *cmd)
> +{
> + const struct pcidas64_board *board = comedi_board(dev);
> + unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
> + unsigned int aref0 = CR_AREF(cmd->chanlist[0]);
> + int i;
> +
> + for (i = 1; i < cmd->chanlist_len; i++) {
> + unsigned int aref = CR_AREF(cmd->chanlist[i]);
> +
> + if (aref != aref0) {
> + dev_err(dev->class_dev,
> + "chanlist must use the same analog reference\n");
> + return -EINVAL;
> + }
> + }
> +
> + if (board->layout == LAYOUT_4020) {
> + for (i = 1; i < cmd->chanlist_len; i++) {
> + unsigned int chan = CR_CHAN(cmd->chanlist[i]);
> + if (chan != chan0 + i) {
> + dev_err(dev->class_dev,
> + "chanlist must use consecutive channels\n");
> + return -EINVAL;
> + }
> + }
> + if (cmd->chanlist_len == 3) {
> + dev_err(dev->class_dev,
> + "chanlist cannot be 3 channels long, use 1, 2, or 4 channels\n");
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
> struct comedi_cmd *cmd)
> {
> const struct pcidas64_board *thisboard = comedi_board(dev);
> int err = 0;
> unsigned int tmp_arg, tmp_arg2;
> - int i;
> - int aref;
> unsigned int triggers;
>
> /* Step 1 : check if triggers are trivially valid */
> @@ -2097,36 +2132,9 @@ static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
> if (err)
> return 4;
>
> - /* make sure user is doesn't change analog reference mid chanlist */
> - if (cmd->chanlist) {
> - aref = CR_AREF(cmd->chanlist[0]);
> - for (i = 1; i < cmd->chanlist_len; i++) {
> - if (aref != CR_AREF(cmd->chanlist[i])) {
> - comedi_error(dev,
> - "all elements in chanlist must use the same analog reference");
> - err++;
> - break;
> - }
> - }
> - /* check 4020 chanlist */
> - if (thisboard->layout == LAYOUT_4020) {
> - unsigned int first_channel = CR_CHAN(cmd->chanlist[0]);
> - for (i = 1; i < cmd->chanlist_len; i++) {
> - if (CR_CHAN(cmd->chanlist[i]) !=
> - first_channel + i) {
> - comedi_error(dev,
> - "chanlist must use consecutive channels");
> - err++;
> - break;
> - }
> - }
> - if (cmd->chanlist_len == 3) {
> - comedi_error(dev,
> - "chanlist cannot be 3 channels long, use 1, 2, or 4 channels");
> - err++;
> - }
> - }
> - }
> + /* Step 5: check channel list */
> +
> + err |= cb_pcidas64_ai_check_chanlist(dev, s, cmd);
>
> if (err)
> return 5;
As for the remarks in patch 02, it's possible for chanlist to be NULL or
for chanlist_len to be 0, so cb_pcidas64_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_pcidas64_ai_check_chanlist().
The original code is buggy as well because it accesses cmd->chanlist[0]
without checking cmd->chanlist_len.
> @@ -3246,13 +3254,31 @@ static int ao_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
> return 0;
> }
>
> +static int cb_pcidas64_ao_check_chanlist(struct comedi_device *dev,
> + struct comedi_subdevice *s,
> + struct comedi_cmd *cmd)
> +{
> + unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
> + int i;
> +
> + for (i = 1; i < cmd->chanlist_len; i++) {
> + unsigned int chan = CR_CHAN(cmd->chanlist[i]);
> +
> + if (chan != chan0 + i) {
> + dev_err(dev->class_dev,
> + "chanlist must use consecutive channels");
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> static int ao_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
> struct comedi_cmd *cmd)
> {
> const struct pcidas64_board *thisboard = comedi_board(dev);
> int err = 0;
> unsigned int tmp_arg;
> - int i;
>
> /* Step 1 : check if triggers are trivially valid */
>
> @@ -3313,17 +3339,9 @@ static int ao_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
> if (err)
> return 4;
>
> - if (cmd->chanlist) {
> - unsigned int first_channel = CR_CHAN(cmd->chanlist[0]);
> - for (i = 1; i < cmd->chanlist_len; i++) {
> - if (CR_CHAN(cmd->chanlist[i]) != first_channel + i) {
> - comedi_error(dev,
> - "chanlist must use consecutive channels");
> - err++;
> - break;
> - }
> - }
> - }
> + /* Step 5: check channel list */
> +
> + err |= cb_pcidas64_ao_check_chanlist(dev, s, cmd);
>
> if (err)
> return 5;
>
Ditto for calling cb_pcidas64_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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