Re: [PATCH] IBM Power RAID driver (ipr) 2.0.6

[Brian King <brking@us.ibm.com>]

Matthew Wilcox wrote:
> On Mon, May 10, 2004 at 03:38:57PM -0500, James Bottomley wrote:
> 
>>On Tue, 2004-05-04 at 12:52, Brian King wrote:
>>
>>>Here is the latest version of the LLD for the IBM Power RAID family of
>>>adapters. This includes several IBM iSeries and pSeries SCSI adapters.
>>>Please apply.
>>
>>The problem is your use of list_head pointers in packed structures.  You
>>can't simply pass a pointer to a misaligned structure to a common kernel
>>function and expect it to work: the packed attribute is lost doing this
>>and what you end up with is a misaligned pointer reference.
> 
> 
> It also causes gcc to pessimise references to this structure; often
> doing byte-loads instead of larger quantities.  Why does this struct
> need to be packed? 

It is a shared structure with the adapter with a little bit of added
driver data at the end of it. I'll roll a patch to clean this up. The
better way to do this is probably to break out the data that needs to be
packed into its own structure.

-Brian

-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center