Re: Bug#609371: linux-image-2.6.37-trunk-sparc64: module scsi_mod:Unknown relocation: 36

[David Miller]

From: "Bernhard R. Link" <brl+ccmadness@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Mon, 17 Jan 2011 15:39:54 +0100

> * David Miller <davem@xxxxxxxxxxxxx> [110117 07:07]:
>> Ugh, and I just noticed that include/linux/klist.h does this fixed
>> alignment of "4" too, where is this stuff coming from?  It's
>> wrong on 64-bit, at best.  But I can't see the impetus behind doing
>> this at all in the first place.
> 
> Is that actually misaligned? Unless I still mix things up, that is in the
> struct thus should be fine (i.e. the "d" case in my example above).

On CRIS, structs naturally align on a byte-boundary only.

However, code using klists encodes a binary state in the lowest bit of
klist pointers.  So this assumes that the structures will be at least
2 byte aligned, which will not be true on CRIS.

We have a lot of other code which uses this trick (encoding 1 or 2
bits of binary state into the lowest bits of a pointer) so I'm
surprised this workaround isn't needed elsewhere for CRIS too.
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