From: Jens Axboe <jaxboe@fusionio.com>
Date: Thu, 26 May 2011 19:01:38 +0000 (+0200)
Subject: block: fix oops on !disk->queue and sysfs discard alignment display
X-Git-Tag: v3.0-rc1~42^2~9
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4fa3424c66255ba1e07b26becfc3d6cab0fdf65;p=pandora-kernel.git

block: fix oops on !disk->queue and sysfs discard alignment display

Eric Dumazet reports:

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At boot, I have a crash in part_discard_alignment_show+0x1b/0x50

CR2 : 000006ac

fault in : mov    0x2c(%rcx),%edx

I suspect commit 23ceb5b7719e9276d4 (block: Remove extra
discard_alignment from hd_struct) being in fault

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Not quite known how ->queue can be NULL while the sysfs entry
exists, but lets play it safe and check for a NULL queue.
The rest of the sysfs show strategies in check.c do not dereference
disk->queue.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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