[PATCH] md: clear the congested_fn when stopping a raid5

If this mddev and queue got reused for another array that doesn't register a
congested_fn, this function would get called incorretly.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6c06e825cff5..a9852dbdfd66 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3325,6 +3325,7 @@ static int do_md_stop(mddev_t * mddev, int mode)
                         mddev->queue->merge_bvec_fn = NULL;
                         mddev->queue->unplug_fn = NULL;
                         mddev->queue->issue_flush_fn = NULL;
+                        mddev->queue->backing_dev_info.congested_fn = NULL;
                         if (mddev->pers->sync_request)
                                 sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ae30e87bf505..4dd252864f52 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3646,8 +3646,8 @@ static int run(mddev_t *mddev)
 
         mddev->queue->unplug_fn = raid5_unplug_device;
         mddev->queue->issue_flush_fn = raid5_issue_flush;
-        mddev->queue->backing_dev_info.congested_fn = raid5_congested;
         mddev->queue->backing_dev_info.congested_data = mddev;
+        mddev->queue->backing_dev_info.congested_fn = raid5_congested;
 
         mddev->array_size =  mddev->size * (conf->previous_raid_disks -
                                             conf->max_degraded);
@@ -3678,6 +3678,7 @@ static int stop(mddev_t *mddev)
         mddev->thread = NULL;
         shrink_stripes(conf);
         kfree(conf->stripe_hashtbl);
+        mddev->queue->backing_dev_info.congested_fn = NULL;
         blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
         sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);
         kfree(conf->disks);