staging: comedi: das16: prevent "empty acquisition" async command
authorH Hartley Sweeten <hsweeten@visionengravers.com>
Tue, 9 Sep 2014 23:15:46 +0000 (16:15 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 11 Sep 2014 21:35:20 +0000 (14:35 -0700)
This driver currently allows a cmd->stop_src == TRIG_COUNT with a cmd->stop_arg
of 0. The (*do_cmd) then sets up and starts the command without handling the "empty
acquisition". This results in the interrupt function trying to transfer 0 data
samples.

Validate that the cmd->stop_arg is >= 1 in the (*do_cmdtest) to prevent the
"empty acquisition".

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/comedi/drivers/das16.c

index baec9f2bd43c2bc7cf10c47c7b4e72a9d0b30a40..2d8e86cec47a399cc3bc3f8150361caa8ecf44a8 100644 (file)
@@ -692,7 +692,9 @@ static int das16_cmd_test(struct comedi_device *dev, struct comedi_subdevice *s,
                err |= cfc_check_trigger_arg_min(&cmd->convert_arg,
                                                 board->ai_speed);
 
-       if (cmd->stop_src == TRIG_NONE)
+       if (cmd->stop_src == TRIG_COUNT)
+               err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
+       else    /* TRIG_NONE */
                err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
        if (err)