md/linear: rcu_dereference outside read-lock section
According to the comment in linear_stop function
rcu_dereference in linear_start and linear_stop functions
occurs under reconfig_mutex. The patch represents this
agreement in code and prevents lockdep complaint.
Found by Linux Driver Verification project (linuxtesting.org)
Signed-off-by: Denis Efremov <yefremov.denis@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index fa211d8..92c64d1 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -244,7 +244,9 @@
if (!newconf)
return -ENOMEM;
- oldconf = rcu_dereference(mddev->private);
+ oldconf = rcu_dereference_protected(mddev->private,
+ lockdep_is_held(
+ &mddev->reconfig_mutex));
mddev->raid_disks++;
rcu_assign_pointer(mddev->private, newconf);
md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
@@ -256,7 +258,10 @@
static int linear_stop (struct mddev *mddev)
{
- struct linear_conf *conf = mddev->private;
+ struct linear_conf *conf =
+ rcu_dereference_protected(mddev->private,
+ lockdep_is_held(
+ &mddev->reconfig_mutex));
/*
* We do not require rcu protection here since