Bug#582281: Upstream fix

[Stephen Powell <zlinuxman@wowway.com>]

On Tue, 20 Jul 2010 09:55:58 -0400 (EDT), Peter Oberparleiter wrote:
> 
> A fix for this problem has been accepted for inclusion into 2.6.35-rc5. See:
> 
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=cffab6bc5511cd6f67a60bf16b62de4267b68c4c

Hello, Peter.  I finally got a chance to take a look at this today.
I can't apply the patch as written to my 2.6.32 source code due to changes
between 2.6.32 and 2.6.35 that will cause the patch to not apply.
However, I did look at the patch.  While I confess to being a complete
novice in the C language, the patch doesn't look quite right to me.
Consider the following excerpt from the patch:

+       if ((info->cu_type == 0x6310 && info->dev_type == 0x9336) ||
+           (info->cu_type == 0x3880 && info->dev_type == 0x3370))
+               labelsect = info->label_block;
+       else
+               labelsect = info->label_block * (blocksize >> 9);

This is unexpected.  I expected that last line to be

+               labelsect = info->label_block * (blocksize/512)

My concern is not for FBA DASD.  I expect your code to execute correctly
for FBA DASD.  My concern is that it will break for CKD DASD.  Are you
sure that this is correct?  Did you test the fix for CKD DASD as well
as FBA DASD?

Respectfully submitted.

-- 
  .''`.     Stephen Powell    
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