md/raid10: fix two bugs in handling of known-bad-blocks.

If we discover a bad block when reading we split the request and
potentially read some of it from a different device.

The code path of this has two bugs in RAID10.
1/ we get a spin_lock with _irq, but unlock without _irq!!
2/ The calculation of 'sectors_handled' is wrong, as can be clearly
   seen by comparison with raid1.c

This leads to at least 2 warnings and a probable crash is a RAID10
ever had known bad blocks.

Cc: stable@vger.kernel.org (v3.1+)
Fixes: 856e08e23762dfb92ffc68fd0a8d228f9e152160
Reported-by: Damian Nowak <spam@nowaker.net>
URL: https://bugzilla.kernel.org/show_bug.cgi?id=68181
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index c504e8389e69..65285211568f 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1319,7 +1319,7 @@ read_again:
                         /* Could not read all from this device, so we will
                          * need another r10_bio.
                          */
-                        sectors_handled = (r10_bio->sectors + max_sectors
+                        sectors_handled = (r10_bio->sector + max_sectors
                                            - bio->bi_sector);
                         r10_bio->sectors = max_sectors;
                         spin_lock_irq(&conf->device_lock);
@@ -1327,7 +1327,7 @@ read_again:
                                 bio->bi_phys_segments = 2;
                         else
                                 bio->bi_phys_segments++;
-                        spin_unlock(&conf->device_lock);
+                        spin_unlock_irq(&conf->device_lock);
                         /* Cannot call generic_make_request directly
                          * as that will be queued in __generic_make_request
                          * and subsequent mempool_alloc might block