Re: ide_register_hw(): buggy code

[Peter Teoh]

On Tue, Mar 4, 2008 at 6:29 AM, Bartlomiej Zolnierkiewicz
<bzolnier@xxxxxxxxx> wrote:
>
>  Hi,
>
>
>  On Monday 03 March 2008, Peter Teoh wrote:
>  > On Sun, Mar 2, 2008 at 11:19 PM, Adrian Bunk <bunk@xxxxxxxxxx> wrote:
>  > > The Coverity checker spotted the following bogus change to
>  > >  ide_register_hw() in commit 9e016a719209d95338e314b46c3012cc7feaaeec:
>  > >
>  > >  <--  snip  -->
>  > >
>  > >  ...
>  > >  +               hwif = ide_deprecated_find_port(hw->io_ports[IDE_DATA_OFFSET]);
>  > >  +               index = hwif->index;
>  > >  +               if (hwif)
>  > >  +                       goto found;
>  > >                 for (index = 0; index < MAX_HWIFS; index++)
>  > >  ...
>  > >
>  > >  <--  snip  -->
>  > >
>  > >  It's impossible to reach the for() loop without Oopsing before.
>
>  [ iff free hwif is not found (unlikely case) ]
>
>
>  > >  Can you either fix this for 2.6.25 or push your patch that removes
>  > >  ide_register_hw() for 2.6.25?
>  > >
>  >
>  > My question is:
>  >
>  > a.   why is "retry=1", and then the do while loop always end up the
>  > loop being one round executed only?   Why not just remove the while
>  > loop entirely?
>
>  the whole ide_register_hw() is already gone in IDE tree
>  (these patches are scheduled for 2.6.26)
>
>
>  > b.   not sure if your statement above implied this, but checking for
>  > hwif!=0 should be before index.  ???
>  >
>  > c.   "index = hwif->index;" should not be there, but after "found".
>  > Is that correct?
>
>  Yes, could you please re-do your patch to contain:
>
>  - only 'hwif->index' change
>  - proper patch description
>  - Signed-off-by: line
>
>  so I could merge it?


Description:

Relocating the index to come after finding the hwif pointer.

Thanks.

-- 
Regards,
Peter Teoh
Signed-off-by: Peter Teoh <htmldeveloper@xxxxxxxxx>

--- drivers/ide/ide.c.orig	2008-03-04 08:26:11.000000000 +0800
+++ drivers/ide/ide.c	2008-03-04 09:07:44.000000000 +0800
@@ -667,7 +667,6 @@ int ide_register_hw(hw_regs_t *hw, void 
 
 	do {
 		hwif = ide_deprecated_find_port(hw->io_ports[IDE_DATA_OFFSET]);
-		index = hwif->index;
 		if (hwif)
 			goto found;
 		for (index = 0; index < MAX_HWIFS; index++)
@@ -675,6 +674,7 @@ int ide_register_hw(hw_regs_t *hw, void 
 	} while (retry--);
 	return -1;
 found:
+	index = hwif->index;
 	if (hwif->present)
 		ide_unregister(index, 0, 1);
 	else if (!hwif->hold)