linux-kernel - Re: [PATCH 4/6] staging: comedi: usbduxsigma: round down AI scan_begin

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <55B26ED2.1070909@berndporr.me.uk>
Date:	Fri, 24 Jul 2015 17:58:58 +0100
From:	Bernd Porr <mail@...ndporr.me.uk>
To:	Ian Abbott <abbotti@....co.uk>
CC:	driverdev-devel@...uxdriverproject.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	H Hartley Sweeten <hsweeten@...ionengravers.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] staging: comedi: usbduxsigma: round down AI scan_begin_arg
 at step 4.

Reviewed-by: Bernd Porr <mail@...ndporr.me.uk>

Ian Abbott wrote:
> The return value of the `cmdtest` handler for a subdevice checks the
> prospective new command in various steps and returns the step number at
> which any problem was detected, or 0 if no problem was detected.  It is
> allowed to modify the command in various ways at each step.  Corrections
> for out-of-range values are generally made at step 3, and minor
> adjustments such as rounding are generally made at step 4.
> 
> The `cmdtest` handler for the AI subdevice (`usbduxsigma_ai_cmdtest()`)
> currently modifies `cmd->scan_begin_arg` to bring it into range and
> round it down at step 3.  Move the rounding down part to step 4 to
> follow the usual Comedi convention.
> 
> Signed-off-by: Ian Abbott <abbotti@....co.uk>
> ---
>  drivers/staging/comedi/drivers/usbduxsigma.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c b/drivers/staging/comedi/drivers/usbduxsigma.c
> index 65a0df4..4655048 100644
> --- a/drivers/staging/comedi/drivers/usbduxsigma.c
> +++ b/drivers/staging/comedi/drivers/usbduxsigma.c
> @@ -518,17 +518,12 @@ static int usbduxsigma_ai_cmdtest(struct comedi_device *dev,
>  		 */
>  		err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
>  						    (125000 * interval));
> -
> -		tmp = (cmd->scan_begin_arg / 125000) * 125000;
>  	} else {
>  		/* full speed */
>  		/* 1kHz scans every USB frame */
>  		err |= comedi_check_trigger_arg_min(&cmd->scan_begin_arg,
>  						    1000000);
> -
> -		tmp = (cmd->scan_begin_arg / 1000000) * 1000000;
>  	}
> -	err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, tmp);
>  
>  	err |= comedi_check_trigger_arg_is(&cmd->scan_end_arg,
>  					   cmd->chanlist_len);
> @@ -541,6 +536,14 @@ static int usbduxsigma_ai_cmdtest(struct comedi_device *dev,
>  	if (err)
>  		return 3;
>  
> +	/* Step 4: fix up any arguments */
> +
> +	tmp = rounddown(cmd->scan_begin_arg, high_speed ? 125000 : 1000000);
> +	err |= comedi_check_trigger_arg_is(&cmd->scan_begin_arg, tmp);
> +
> +	if (err)
> +		return 4;
> +
>  	return 0;
>  }
>  

-- 
http://www.berndporr.me.uk
http://www.linux-usb-daq.co.uk
http://www.imdb.com/name/nm3293421/
+44 (0)7840 340069
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/