[PATCH net-next v1 3/4] net: add granular lock for the netdev netlink socket

[Stanislav Fomichev]

As we move away from rtnl_lock for queue ops, introduce
per-netdev_nl_sock lock.

Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>
---
 include/net/netdev_netlink.h | 1 +
 net/core/netdev-genl.c       | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/net/netdev_netlink.h b/include/net/netdev_netlink.h
index 1599573d35c9..075962dbe743 100644
--- a/include/net/netdev_netlink.h
+++ b/include/net/netdev_netlink.h
@@ -5,6 +5,7 @@
 #include <linux/list.h>
 
 struct netdev_nl_sock {
+	struct mutex lock;
 	struct list_head bindings;
 };
 
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index a219be90c739..8acdeeae24e7 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -859,6 +859,7 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
 		goto err_genlmsg_free;
 	}
 
+	mutex_lock(&priv->lock);
 	rtnl_lock();
 
 	netdev = __dev_get_by_index(genl_info_net(info), ifindex);
@@ -925,6 +926,7 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
 	net_devmem_unbind_dmabuf(binding);
 err_unlock:
 	rtnl_unlock();
+	mutex_unlock(&priv->lock);
 err_genlmsg_free:
 	nlmsg_free(rsp);
 	return err;
@@ -933,6 +935,7 @@ int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info)
 void netdev_nl_sock_priv_init(struct netdev_nl_sock *priv)
 {
 	INIT_LIST_HEAD(&priv->bindings);
+	mutex_init(&priv->lock);
 }
 
 void netdev_nl_sock_priv_destroy(struct netdev_nl_sock *priv)
@@ -940,11 +943,13 @@ void netdev_nl_sock_priv_destroy(struct netdev_nl_sock *priv)
 	struct net_devmem_dmabuf_binding *binding;
 	struct net_devmem_dmabuf_binding *temp;
 
+	mutex_lock(&priv->lock);
 	list_for_each_entry_safe(binding, temp, &priv->bindings, list) {
 		rtnl_lock();
 		net_devmem_unbind_dmabuf(binding);
 		rtnl_unlock();
 	}
+	mutex_unlock(&priv->lock);
 }
 
 static int netdev_genl_netdevice_event(struct notifier_block *nb,
-- 
2.48.1