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>
This commit is contained in:
Denis Efremov
2012-10-11 13:08:02 +11:00
committed by NeilBrown
parent 02f3939e1a
commit bc78c57388

View File

@@ -244,7 +244,9 @@ static int linear_add(struct mddev *mddev, struct md_rdev *rdev)
if (!newconf) if (!newconf)
return -ENOMEM; return -ENOMEM;
oldconf = rcu_dereference(mddev->private); oldconf = rcu_dereference_protected(mddev->private,
lockdep_is_held(
&mddev->reconfig_mutex));
mddev->raid_disks++; mddev->raid_disks++;
rcu_assign_pointer(mddev->private, newconf); rcu_assign_pointer(mddev->private, newconf);
md_set_array_sectors(mddev, linear_size(mddev, 0, 0)); md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
@@ -256,7 +258,10 @@ static int linear_add(struct mddev *mddev, struct md_rdev *rdev)
static int linear_stop (struct mddev *mddev) 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 * We do not require rcu protection here since