nvmet: Pass lockdep expression to RCU lists

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>

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 28438b833c1b0e97bea34b2436ed69e45a7043ba..35810a0a8d2122dad7eb1e3dc6398b6c096ed8b2 100644 (file)
--- 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;
@@ -1172,7 +1173,8 @@ 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);
 }