net: core: add generic lockdep keys

Some interface types could be nested.
(VLAN, BONDING, TEAM, MACSEC, MACVLAN, IPVLAN, VIRT_WIFI, VXLAN, etc..)
These interface types should set lockdep class because, without lockdep
class key, lockdep always warn about unexisting circular locking.

In the current code, these interfaces have their own lockdep class keys and
these manage itself. So that there are so many duplicate code around the
/driver/net and /net/.
This patch adds new generic lockdep keys and some helper functions for it.

This patch does below changes.
a) Add lockdep class keys in struct net_device
   - qdisc_running, xmit, addr_list, qdisc_busylock
   - these keys are used as dynamic lockdep key.
b) When net_device is being allocated, lockdep keys are registered.
   - alloc_netdev_mqs()
c) When net_device is being free'd llockdep keys are unregistered.
   - free_netdev()
d) Add generic lockdep key helper function
   - netdev_register_lockdep_key()
   - netdev_unregister_lockdep_key()
   - netdev_update_lockdep_key()
e) Remove unnecessary generic lockdep macro and functions
f) Remove unnecessary lockdep code of each interfaces.

After this patch, each interface modules don't need to maintain
their lockdep keys.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 11 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 17bd8f539bc7..b2d34c49cbe6 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -799,9 +799,6 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = {
 };
 EXPORT_SYMBOL(pfifo_fast_ops);
 
-static struct lock_class_key qdisc_tx_busylock;
-static struct lock_class_key qdisc_running_key;
-
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 			  const struct Qdisc_ops *ops,
 			  struct netlink_ext_ack *extack)
@@ -854,17 +851,9 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 	}
 
 	spin_lock_init(&sch->busylock);
-	lockdep_set_class(&sch->busylock,
-			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
-
 	/* seqlock has the same scope of busylock, for NOLOCK qdisc */
 	spin_lock_init(&sch->seqlock);
-	lockdep_set_class(&sch->busylock,
-			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
-
 	seqcount_init(&sch->running);
-	lockdep_set_class(&sch->running,
-			  dev->qdisc_running_key ?: &qdisc_running_key);
 
 	sch->ops = ops;
 	sch->flags = ops->static_flags;
@@ -875,6 +864,12 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 	dev_hold(dev);
 	refcount_set(&sch->refcnt, 1);
 
+	if (sch != &noop_qdisc) {
+		lockdep_set_class(&sch->busylock, &dev->qdisc_tx_busylock_key);
+		lockdep_set_class(&sch->seqlock, &dev->qdisc_tx_busylock_key);
+		lockdep_set_class(&sch->running, &dev->qdisc_running_key);
+	}
+
 	return sch;
 errout1:
 	kfree(p);