From 3ec67ac1a399d576d48b0736096bcce7721fe3cf Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@cse.unsw.edu.au>
Date: Fri, 9 Sep 2005 16:23:40 -0700
Subject: [PATCH] md: fix minor error in raid10 read-balancing calculation.

'this_sector' is a virtual (array) address while 'head_position' is a physical
(device) address, so substraction doesn't make any sense.  devs[slot].addr
should be used instead of this_sector.

However, this patch doesn't make much practical different to the read
balancing due to the effects of later code.

Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 62ebb1bc..7239079 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -538,7 +538,8 @@ static int read_balance(conf_t *conf, r10bio_t *r10_bio)
 	}
 
 
-	current_distance = abs(this_sector - conf->mirrors[disk].head_position);
+	current_distance = abs(r10_bio->devs[slot].addr -
+			       conf->mirrors[disk].head_position);
 
 	/* Find the disk whose head is closest */
 
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