1 files changed, 222 insertions, 1 deletions

diff --git a/net/devlink/core.c b/net/devlink/core.c
index 6cec4afb01fb..6984877e9f10 100644
--- a/net/devlink/core.c
+++ b/net/devlink/core.c
@@ -16,6 +16,222 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(devlink_trap_report);
 
 DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
 
+static struct devlink *devlinks_xa_get(unsigned long index)
+{
+	struct devlink *devlink;
+
+	rcu_read_lock();
+	devlink = xa_find(&devlinks, &index, index, DEVLINK_REGISTERED);
+	if (!devlink || !devlink_try_get(devlink))
+		devlink = NULL;
+	rcu_read_unlock();
+	return devlink;
+}
+
+/* devlink_rels xarray contains 1:1 relationships between
+ * devlink object and related nested devlink instance.
+ * The xarray index is used to get the nested object from
+ * the nested-in object code.
+ */
+static DEFINE_XARRAY_FLAGS(devlink_rels, XA_FLAGS_ALLOC1);
+
+#define DEVLINK_REL_IN_USE XA_MARK_0
+
+struct devlink_rel {
+	u32 index;
+	refcount_t refcount;
+	u32 devlink_index;
+	struct {
+		u32 devlink_index;
+		u32 obj_index;
+		devlink_rel_notify_cb_t *notify_cb;
+		devlink_rel_cleanup_cb_t *cleanup_cb;
+		struct work_struct notify_work;
+	} nested_in;
+};
+
+static void devlink_rel_free(struct devlink_rel *rel)
+{
+	xa_erase(&devlink_rels, rel->index);
+	kfree(rel);
+}
+
+static void __devlink_rel_get(struct devlink_rel *rel)
+{
+	refcount_inc(&rel->refcount);
+}
+
+static void __devlink_rel_put(struct devlink_rel *rel)
+{
+	if (refcount_dec_and_test(&rel->refcount))
+		devlink_rel_free(rel);
+}
+
+static void devlink_rel_nested_in_notify_work(struct work_struct *work)
+{
+	struct devlink_rel *rel = container_of(work, struct devlink_rel,
+					       nested_in.notify_work);
+	struct devlink *devlink;
+
+	devlink = devlinks_xa_get(rel->nested_in.devlink_index);
+	if (!devlink)
+		goto rel_put;
+	if (!devl_trylock(devlink)) {
+		devlink_put(devlink);
+		goto reschedule_work;
+	}
+	if (!devl_is_registered(devlink)) {
+		devl_unlock(devlink);
+		devlink_put(devlink);
+		goto rel_put;
+	}
+	if (!xa_get_mark(&devlink_rels, rel->index, DEVLINK_REL_IN_USE))
+		rel->nested_in.cleanup_cb(devlink, rel->nested_in.obj_index, rel->index);
+	rel->nested_in.notify_cb(devlink, rel->nested_in.obj_index);
+	devl_unlock(devlink);
+	devlink_put(devlink);
+
+rel_put:
+	__devlink_rel_put(rel);
+	return;
+
+reschedule_work:
+	schedule_work(&rel->nested_in.notify_work);
+}
+
+static void devlink_rel_nested_in_notify_work_schedule(struct devlink_rel *rel)
+{
+	__devlink_rel_get(rel);
+	schedule_work(&rel->nested_in.notify_work);
+}
+
+static struct devlink_rel *devlink_rel_alloc(void)
+{
+	struct devlink_rel *rel;
+	static u32 next;
+	int err;
+
+	rel = kzalloc(sizeof(*rel), GFP_KERNEL);
+	if (!rel)
+		return ERR_PTR(-ENOMEM);
+
+	err = xa_alloc_cyclic(&devlink_rels, &rel->index, rel,
+			      xa_limit_32b, &next, GFP_KERNEL);
+	if (err) {
+		kfree(rel);
+		return ERR_PTR(err);
+	}
+
+	refcount_set(&rel->refcount, 1);
+	INIT_WORK(&rel->nested_in.notify_work,
+		  &devlink_rel_nested_in_notify_work);
+	return rel;
+}
+
+static void devlink_rel_put(struct devlink *devlink)
+{
+	struct devlink_rel *rel = devlink->rel;
+
+	if (!rel)
+		return;
+	xa_clear_mark(&devlink_rels, rel->index, DEVLINK_REL_IN_USE);
+	devlink_rel_nested_in_notify_work_schedule(rel);
+	__devlink_rel_put(rel);
+	devlink->rel = NULL;
+}
+
+void devlink_rel_nested_in_clear(u32 rel_index)
+{
+	xa_clear_mark(&devlink_rels, rel_index, DEVLINK_REL_IN_USE);
+}
+
+int devlink_rel_nested_in_add(u32 *rel_index, u32 devlink_index,
+			      u32 obj_index, devlink_rel_notify_cb_t *notify_cb,
+			      devlink_rel_cleanup_cb_t *cleanup_cb,
+			      struct devlink *devlink)
+{
+	struct devlink_rel *rel = devlink_rel_alloc();
+
+	ASSERT_DEVLINK_NOT_REGISTERED(devlink);
+
+	if (IS_ERR(rel))
+		return PTR_ERR(rel);
+
+	rel->devlink_index = devlink->index;
+	rel->nested_in.devlink_index = devlink_index;
+	rel->nested_in.obj_index = obj_index;
+	rel->nested_in.notify_cb = notify_cb;
+	rel->nested_in.cleanup_cb = cleanup_cb;
+	*rel_index = rel->index;
+	xa_set_mark(&devlink_rels, rel->index, DEVLINK_REL_IN_USE);
+	devlink->rel = rel;
+	return 0;
+}
+
+/**
+ * devlink_rel_nested_in_notify - Notify the object this devlink
+ *				  instance is nested in.
+ * @devlink: devlink
+ *
+ * This is called upon network namespace change of devlink instance.
+ * In case this devlink instance is nested in another devlink object,
+ * a notification of a change of this object should be sent
+ * over netlink. The parent devlink instance lock needs to be
+ * taken during the notification preparation.
+ * However, since the devlink lock of nested instance is held here,
+ * we would end with wrong devlink instance lock ordering and
+ * deadlock. Therefore the work is utilized to avoid that.
+ */
+void devlink_rel_nested_in_notify(struct devlink *devlink)
+{
+	struct devlink_rel *rel = devlink->rel;
+
+	if (!rel)
+		return;
+	devlink_rel_nested_in_notify_work_schedule(rel);
+}
+
+static struct devlink_rel *devlink_rel_find(unsigned long rel_index)
+{
+	return xa_find(&devlink_rels, &rel_index, rel_index,
+		       DEVLINK_REL_IN_USE);
+}
+
+static struct devlink *devlink_rel_devlink_get(u32 rel_index)
+{
+	struct devlink_rel *rel;
+	u32 devlink_index;
+
+	if (!rel_index)
+		return NULL;
+	xa_lock(&devlink_rels);
+	rel = devlink_rel_find(rel_index);
+	if (rel)
+		devlink_index = rel->devlink_index;
+	xa_unlock(&devlink_rels);
+	if (!rel)
+		return NULL;
+	return devlinks_xa_get(devlink_index);
+}
+
+int devlink_rel_devlink_handle_put(struct sk_buff *msg, struct devlink *devlink,
+				   u32 rel_index, int attrtype,
+				   bool *msg_updated)
+{
+	struct net *net = devlink_net(devlink);
+	struct devlink *rel_devlink;
+	int err;
+
+	rel_devlink = devlink_rel_devlink_get(rel_index);
+	if (!rel_devlink)
+		return 0;
+	err = devlink_nl_put_nested_handle(msg, net, rel_devlink, attrtype);
+	devlink_put(rel_devlink);
+	if (!err && msg_updated)
+		*msg_updated = true;
+	return err;
+}
+
 void *devlink_priv(struct devlink *devlink)
 {
 	return &devlink->priv;
@@ -97,6 +313,7 @@ static void devlink_release(struct work_struct *work)
 
 	mutex_destroy(&devlink->lock);
 	lockdep_unregister_key(&devlink->lock_key);
+	put_device(devlink->dev);
 	kfree(devlink);
 }
 
@@ -142,6 +359,7 @@ int devl_register(struct devlink *devlink)
 
 	xa_set_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
 	devlink_notify_register(devlink);
+	devlink_rel_nested_in_notify(devlink);
 
 	return 0;
 }
@@ -166,6 +384,7 @@ void devl_unregister(struct devlink *devlink)
 
 	devlink_notify_unregister(devlink);
 	xa_clear_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
+	devlink_rel_put(devlink);
 }
 EXPORT_SYMBOL_GPL(devl_unregister);
 
@@ -210,11 +429,12 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
 	if (ret < 0)
 		goto err_xa_alloc;
 
-	devlink->dev = dev;
+	devlink->dev = get_device(dev);
 	devlink->ops = ops;
 	xa_init_flags(&devlink->ports, XA_FLAGS_ALLOC);
 	xa_init_flags(&devlink->params, XA_FLAGS_ALLOC);
 	xa_init_flags(&devlink->snapshot_ids, XA_FLAGS_ALLOC);
+	xa_init_flags(&devlink->nested_rels, XA_FLAGS_ALLOC);
 	write_pnet(&devlink->_net, net);
 	INIT_LIST_HEAD(&devlink->rate_list);
 	INIT_LIST_HEAD(&devlink->linecard_list);
@@ -261,6 +481,7 @@ void devlink_free(struct devlink *devlink)
 	WARN_ON(!list_empty(&devlink->linecard_list));
 	WARN_ON(!xa_empty(&devlink->ports));
 
+	xa_destroy(&devlink->nested_rels);
 	xa_destroy(&devlink->snapshot_ids);
 	xa_destroy(&devlink->params);
 	xa_destroy(&devlink->ports);