[PATCH 13/22] staging: comedi: adv_pci1710: don't check the chanlist twice
Ian Abbott
abbotti at mev.co.uk
Thu Apr 24 11:05:30 UTC 2014
On 2014-04-24 00:07, H Hartley Sweeten wrote:
> The chanlist is checked in Step 5 of the (*do_cmdtest) there is no
> reason to check it again in the (*do_cmd). The only reasonm its done
> is to get the actual 'seglen', the non-repeating length of the chanlist.
>
> Save the 'seglen' found by pci171x_ai_check_chanlist() in the private
> data and use that in the (*do_cmd).
Since do_cmdtest can be done while a command is running, one needs to be
careful to make sure that any private data modified by do_cmdtest is not
used by the running command, and only used by do_cmd when setting up the
next command.
It's fine in this case though as devpriv->act_chanlist_len is only used
while setting up the next command, although perhaps it ought to be
renamed to devpriv->saved_chanlist_len, possibly by a subsequent patch.
(Also, devpriv->act_chanlist_pos isn't used so can be removed.)
>
> Refactor the error handling in pci171x_ai_check_chanlist() to work like
> the cfc_check_*() helpers.
>
> 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/adv_pci1710.c | 29 +++++++++++++++-------------
> 1 file changed, 16 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
> index 59c8bc4..6698d3c 100644
> --- a/drivers/staging/comedi/drivers/adv_pci1710.c
> +++ b/drivers/staging/comedi/drivers/adv_pci1710.c
> @@ -330,6 +330,7 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
> struct comedi_subdevice *s,
> struct comedi_cmd *cmd)
> {
> + struct pci1710_private *devpriv = dev->private;
> unsigned int chan0 = CR_CHAN(cmd->chanlist[0]);
> unsigned int last_aref = CR_AREF(cmd->chanlist[0]);
> unsigned int next_chan = (chan0 + 1) & s->n_chan;
> @@ -337,8 +338,10 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
> unsigned int seglen;
> int i;
>
> - if (cmd->chanlist_len == 1)
> - return 1; /* seglen=1 */
> + if (cmd->chanlist_len == 1) {
> + devpriv->act_chanlist_len = cmd->chanlist_len;
> + return 0;
> + }
>
> /* first channel is always ok */
> chansegment[0] = cmd->chanlist[0];
> @@ -353,7 +356,7 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
> if (aref == AREF_DIFF && (chan & 1)) {
> dev_err(dev->class_dev,
> "Odd channel cannot be differential input!\n");
> - return 0;
> + return -EINVAL;
> }
>
> if (last_aref == AREF_DIFF)
> @@ -362,7 +365,7 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
> dev_err(dev->class_dev,
> "channel list must be continuous! chanlist[%i]=%d but must be %d or %d!\n",
> i, chan, next_chan, chan0);
> - return 0;
> + return -EINVAL;
> }
>
> /* next correct channel in list */
> @@ -381,10 +384,12 @@ static int pci171x_ai_check_chanlist(struct comedi_device *dev,
> CR_CHAN(cmd->chanlist[i % seglen]),
> CR_RANGE(cmd->chanlist[i % seglen]),
> CR_AREF(chansegment[i % seglen]));
> - return 0;
> + return -EINVAL;
> }
> }
> - return seglen;
> + devpriv->act_chanlist_len = seglen;
> +
> + return 0;
> }
>
> static void setup_channel_list(struct comedi_device *dev,
> @@ -396,7 +401,6 @@ static void setup_channel_list(struct comedi_device *dev,
> struct pci1710_private *devpriv = dev->private;
> unsigned int i, range, chanprog;
>
> - devpriv->act_chanlist_len = seglen;
> devpriv->act_chanlist_pos = 0;
>
> for (i = 0; i < seglen; i++) { /* store range list to card */
> @@ -953,7 +957,6 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
> struct pci1710_private *devpriv = dev->private;
> struct comedi_cmd *cmd = &s->async->cmd;
> unsigned int divisor1 = 0, divisor2 = 0;
> - unsigned int seglen;
> int mode;
>
> if (cmd->convert_src == TRIG_TIMER) {
> @@ -967,10 +970,8 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
>
> start_pacer(dev, -1, 0, 0); /* stop pacer */
>
> - seglen = pci171x_ai_check_chanlist(dev, s, cmd);
> - if (seglen < 1)
> - return -EINVAL;
> - setup_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len, seglen);
> + setup_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len,
> + devpriv->act_chanlist_len);
>
> outb(0, dev->iobase + PCI171x_CLRFIFO);
> outb(0, dev->iobase + PCI171x_CLRINT);
> @@ -1104,7 +1105,9 @@ static int pci171x_ai_cmdtest(struct comedi_device *dev,
>
> /* Step 5: check channel list */
>
> - if (!pci171x_ai_check_chanlist(dev, s, cmd))
> + err |= pci171x_ai_check_chanlist(dev, s, cmd);
> +
> + if (err)
> return 5;
>
> 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 )=-
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