[PATCH 5.4 326/344] nvmet: Pass lockdep expression to RCU lists

Greg Kroah-Hartman
2020-02-21T08:15:34Z

From: Amol Grover <frextrite@gmail.com>

[ Upstream commit 4ac76436a6d07dec1c3c766f234aa787a16e8f65 ]

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: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/target/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 3a67e244e5685..57a4062cbb59e 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -555,7 +555,8 @@ 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;
@@ -1174,7 +1175,8 @@ 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);
}

--
2.20.1