md/raid1: fix bug in read_balance introduced by hot-replace
When we added hot_replace we doubled the number of devices
that could be in a RAID1 array. So we doubled how far read_balance
would search. Unfortunately we didn't double the point at which
it looped back to the beginning - so it effectively loops over
all non-replacement disks twice.
This doesn't cause bad behaviour, but it pointless and means we
never read from replacement devices.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 39b2a8a..34b4665 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -517,8 +517,8 @@
int bad_sectors;
int disk = start_disk + i;
- if (disk >= conf->raid_disks)
- disk -= conf->raid_disks;
+ if (disk >= conf->raid_disks * 2)
+ disk -= conf->raid_disks * 2;
rdev = rcu_dereference(conf->mirrors[disk].rdev);
if (r1_bio->bios[disk] == IO_BLOCKED