lkml.org 
[lkml]   [2002]   [Apr]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: WatchDog Driver Updates
On Sat, Apr 06, 2002 at 09:49:57PM -0500, Rob Radez wrote:
> I've put up a patch on http://osinvestor.com/bigwatchdog.diff against
> 2.4.19-pre5-ac3. The diff is 33k, and it affects 19 files in drivers/char/,

And the purpose of this patch is...

1. copy_to_user is like memcpy() - it takes two pointers and an integer
size. You're passing it two integers and a pointer:

static int wdt977_ioctl(... unsigned long arg)
...
case WDIOC_GETSTATUS:
if(copy_to_user(arg, &timer_alive, sizeof(timer_alive)))
return -EFAULT;
return 0;

2. sizeof(int) != sizeof(unsigned long). You've changed the ABI in an
unsafe manner on 64-bit machines. The ABI is defined by the ioctl
numbers, which specify an 'int' type.

3. copy_to_user of an int or unsigned long is a bit inefficient. Why
not use put_user to write an int or unsigned long?

4. Unless I'm missing something, WDIOC_GETSTATUS can only ever return
an indication that the timer is open/alive - it's set when the driver
is opened, and cleared when it is closed. Since you can't perform
an ioctl on a closed device, the times that you can perform the ioctl,
it'll always give you a non-zero result.

5. WDIOC_GETSTATUS is supposed to return the WDIOF_* flags. Returning
"watchdog active" as bit 0 causes it to indicate WDIOF_OVERHEAT.

--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:25    [W:0.085 / U:3.800 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site