[md PATCH 15/18] md/raid5: add rcu protection to rdev accesses in raid5_status.

NeilBrown
2016-06-02T06:19:52Z

drivers/md/raid5.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 7da89ee22a31..e9beba258f4f 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7069,10 +7069,12 @@ static void raid5_status(struct seq_file *seq, struct mddev *mddev)
seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
conf->chunk_sectors / 2, mddev->layout);
seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
- for (i = 0; i < conf->raid_disks; i++)
- seq_printf (seq, "%s",
- conf->disks[i].rdev &&
- test_bit(In_sync, &conf->disks[i].rdev->flags) ? "U" : "_");
+ rcu_read_lock();
+ for (i = 0; i < conf->raid_disks; i++) {
+ struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
+ seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
+ }
+ rcu_read_unlock();
seq_printf (seq, "]");
}