1 files changed, 14 insertions, 10 deletions

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 46182b955aef..47ba7d9e81e1 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -120,7 +120,7 @@ struct r5l_log {
 	struct bio_set bs;
 	mempool_t meta_pool;
 
-	struct md_thread *reclaim_thread;
+	struct md_thread __rcu *reclaim_thread;
 	unsigned long reclaim_target;	/* number of space that need to be
 					 * reclaimed.  if it's 0, reclaim spaces
 					 * used by io_units which are in
@@ -792,7 +792,7 @@ static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
 	io->current_bio = r5l_bio_alloc(log);
 	io->current_bio->bi_end_io = r5l_log_endio;
 	io->current_bio->bi_private = io;
-	bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
+	__bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);
 
 	r5_reserve_log_entry(log, io);
 
@@ -1576,17 +1576,18 @@ void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
 
 void r5l_quiesce(struct r5l_log *log, int quiesce)
 {
-	struct mddev *mddev;
+	struct mddev *mddev = log->rdev->mddev;
+	struct md_thread *thread = rcu_dereference_protected(
+		log->reclaim_thread, lockdep_is_held(&mddev->reconfig_mutex));
 
 	if (quiesce) {
 		/* make sure r5l_write_super_and_discard_space exits */
-		mddev = log->rdev->mddev;
 		wake_up(&mddev->sb_wait);
-		kthread_park(log->reclaim_thread->tsk);
+		kthread_park(thread->tsk);
 		r5l_wake_reclaim(log, MaxSector);
 		r5l_do_reclaim(log);
 	} else
-		kthread_unpark(log->reclaim_thread->tsk);
+		kthread_unpark(thread->tsk);
 }
 
 bool r5l_log_disk_error(struct r5conf *conf)
@@ -3063,6 +3064,7 @@ void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
 int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 {
 	struct r5l_log *log;
+	struct md_thread *thread;
 	int ret;
 
 	pr_debug("md/raid:%s: using device %pg as journal\n",
@@ -3121,11 +3123,13 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 	spin_lock_init(&log->tree_lock);
 	INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
 
-	log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
-						 log->rdev->mddev, "reclaim");
-	if (!log->reclaim_thread)
+	thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev,
+				    "reclaim");
+	if (!thread)
 		goto reclaim_thread;
-	log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
+
+	thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
+	rcu_assign_pointer(log->reclaim_thread, thread);
 
 	init_waitqueue_head(&log->iounit_wait);