From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martin Peschke <mpeschke@linux.vnet.ibm.com>
Subject: Re: [PATCH] scsi_debug: Fix endianess in partition table
Date: Wed, 13 Feb 2013 16:16:31 +0100
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To: dgilbert@interlog.com
Cc: linux-scsi <linux-scsi@vger.kernel.org>

On Tue, 2013-02-12 at 09:45 -0500, Douglas Gilbert wrote:
> However since SCSI is big endian and you are introducing
> some "le" code then a line or so of explanation (comments)
> in your revised patch might be helpful.

I would argue that the definition of struct partition itself should be
sufficient explanation. Only scsi_debug failed to assign values in a
correct manner. 

> BTW Finding a big endian architecture to test this patch on is
> not easy.

No big deal ;-) I can help out with test data from my System z (aka
s390x).


Without fix:

[root@zzzzzzzz ~]# xxd -l 512 /dev/sda
<snip>
00001b0: 0000 0000 0000 0000 0000 0000 0000 0001  ................
00001c0: 0100 8307 203f 0000 0020 0000 3fe0 0000  .... ?... ..?...
00001d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00001e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00001f0: 0000 0000 0000 0000 0000 0000 0000 55aa  ..............U.


With fix:

[root@zzzzzzzz ~]# xxd -l 512 /dev/sda
<snip>
00001b0: 0000 0000 0000 0000 0000 0000 0000 0001  ................
00001c0: 0100 8307 203f 2000 0000 e03f 0000 0000  .... ? ....?....
00001d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00001e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00001f0: 0000 0000 0000 0000 0000 0000 0000 55aa  ..............U.


Which makes it exactly look like the table seen on my laptop:

root@xxxxxxxx:~# xxd -l 512 /dev/sdb
<snip>
00001b0: 0000 0000 0000 0000 0000 0000 0000 0001  ................
00001c0: 0100 8307 203f 2000 0000 e03f 0000 0000  .... ? ....?....
00001d0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00001e0: 0000 0000 0000 0000 0000 0000 0000 0000  ................
00001f0: 0000 0000 0000 0000 0000 0000 0000 55aa  ..............U.


Assuming:
modprobe scsi_debug physblk_exp=3 lowest_aligned=7 num_parts=1