From e1083eb498b8c7f70d5699ea547298ea8f983d1d Mon Sep 17 00:00:00 2001
From: Amol Grover <frextrite@gmail.com>
Date: Sat, 11 Jan 2020 13:08:16 +0530
Subject: [PATCH] nvmet: Pass lockdep expression to RCU lists

commit 4ac76436a6d07dec1c3c766f234aa787a16e8f65 upstream.

ctrl->subsys->namespaces and subsys->namespaces are traversed with
list_for_each_entry_rcu outside an RCU read-side critical section but
under the protection of ctrl->subsys->lock and subsys->lock respectively.

Hence, add the corresponding lockdep expression to the list traversal
primitive to silence false-positive lockdep warnings, and harden RCU
lists.

Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 396cbc7ea353..cabe50eaa745 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -550,7 +550,8 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
 	} else {
 		struct nvmet_ns *old;
 
-		list_for_each_entry_rcu(old, &subsys->namespaces, dev_link) {
+		list_for_each_entry_rcu(old, &subsys->namespaces, dev_link,
+					lockdep_is_held(&subsys->lock)) {
 			BUG_ON(ns->nsid == old->nsid);
 			if (ns->nsid < old->nsid)
 				break;
@@ -1164,7 +1165,8 @@ static void nvmet_setup_p2p_ns_map(struct nvmet_ctrl *ctrl,
 
 	ctrl->p2p_client = get_device(req->p2p_client);
 
-	list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link)
+	list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link,
+				lockdep_is_held(&ctrl->subsys->lock))
 		nvmet_p2pmem_ns_add_p2p(ctrl, ns);
 }
 
-- 
2.7.4