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staging: comedi: comedi_test: limit maximum convert_arg

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When testing the parameters for setting up an asynchronous command on
the AI subdevice, limit the maximum conversion period
(`cmd->convert_arg`) so that the number of conversions in a scan
(`cmd->scan_end_arg`, same as `cmd->chanlist_len`) multiplied by the
conversion period fits within an `unsigned int`, as that is used to
limit the minimum scan period (`cmd->scan_begin_arg`).

Also ensure rounding of the conversion period and scan period to the
nearest microsecond both fit in an `unsigned int`.  Do all this in stage
4 ("fix up any arguments") of the command testing.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2015-10-27 16:59:13 +00:00 • committed by Greg Kroah-Hartman
parent 87f64803ca
commit 5afdcad2f8
1 changed files with 21 additions and 21 deletions
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42
drivers/staging/comedi/drivers/comedi_test.c
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@ -234,7 +234,7 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
struct comedi_cmd *cmd)
{
int err = 0;
unsigned int arg;
unsigned int arg, limit;
/* Step 1 : check if triggers are trivially valid */
@ -265,16 +265,8 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
if (cmd->convert_src == TRIG_NOW)
err |= comedi_check_trigger_arg_is(&cmd->convert_arg, 0);
if (cmd->scan_begin_src == TRIG_TIMER) {
err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
NSEC_PER_USEC);
if (cmd->convert_src == TRIG_TIMER) {
err |= comedi_check_trigger_arg_min(&cmd->
scan_begin_arg,
cmd->convert_arg *
cmd->chanlist_len);
}
}
err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
NSEC_PER_USEC);
err |= comedi_check_trigger_arg_min(&cmd->chanlist_len, 1);
err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
@ -290,21 +282,29 @@ static int waveform_ai_cmdtest(struct comedi_device *dev,
/* step 4: fix up any arguments */
if (cmd->scan_begin_src == TRIG_TIMER) {
arg = cmd->scan_begin_arg;
/* round to nearest microsec */
arg = NSEC_PER_USEC *
((arg + (NSEC_PER_USEC / 2)) / NSEC_PER_USEC);
err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
}
if (cmd->convert_src == TRIG_TIMER) {
/* round convert_arg to nearest microsecond */
arg = cmd->convert_arg;
/* round to nearest microsec */
arg = NSEC_PER_USEC *
((arg + (NSEC_PER_USEC / 2)) / NSEC_PER_USEC);
arg = min(arg,
rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
/* limit convert_arg to keep scan_begin_arg in range */
limit = UINT_MAX / cmd->scan_end_arg;
limit = rounddown(limit, (unsigned int)NSEC_PER_SEC);
arg = min(arg, limit);
err |= comedi_check_trigger_arg_is(&cmd->convert_arg, arg);
}
/* round scan_begin_arg to nearest microsecond */
arg = cmd->scan_begin_arg;
arg = min(arg, rounddown(UINT_MAX, (unsigned int)NSEC_PER_USEC));
arg = NSEC_PER_USEC * DIV_ROUND_CLOSEST(arg, NSEC_PER_USEC);
if (cmd->convert_src == TRIG_TIMER) {
/* but ensure scan_begin_arg is large enough */
arg = max(arg, cmd->convert_arg * cmd->scan_end_arg);
}
err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, arg);
if (err)
return 4;