From 7061eb8cfa902daa1ec71d23b5cddb8b4391e72b Mon Sep 17 00:00:00 2001
From: Lijun Pan <ljp@linux.ibm.com>
Date: Mon, 14 Dec 2020 15:19:28 -0600
Subject: [PATCH] net: core: introduce __netdev_notify_peers
References: bsc#1184114 ltc#192237 bsc#1183871 ltc#192139
Patch-mainline: v5.11-rc1
Git-commit: 7061eb8cfa902daa1ec71d23b5cddb8b4391e72b
There are some use cases for netdev_notify_peers in the context
when rtnl lock is already held. Introduce lockless version
of netdev_notify_peers call to save the extra code to call
call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
call_netdevice_notifiers(NETDEV_RESEND_IGMP, dev);
After that, convert netdev_notify_peers to call the new helper.
Suggested-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
include/linux/netdevice.h | 1 +
net/core/dev.c | 22 ++++++++++++++++++++--
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7bf167993c05..259be67644e3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4547,6 +4547,7 @@ void __dev_set_rx_mode(struct net_device *dev);
int dev_set_promiscuity(struct net_device *dev, int inc);
int dev_set_allmulti(struct net_device *dev, int inc);
void netdev_state_change(struct net_device *dev);
+void __netdev_notify_peers(struct net_device *dev);
void netdev_notify_peers(struct net_device *dev);
void netdev_features_change(struct net_device *dev);
/* Load a device via the kmod */
diff --git a/net/core/dev.c b/net/core/dev.c
index a46334906c94..8fa739259041 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1456,6 +1456,25 @@ void netdev_state_change(struct net_device *dev)
}
EXPORT_SYMBOL(netdev_state_change);
+/**
+ * __netdev_notify_peers - notify network peers about existence of @dev,
+ * to be called when rtnl lock is already held.
+ * @dev: network device
+ *
+ * Generate traffic such that interested network peers are aware of
+ * @dev, such as by generating a gratuitous ARP. This may be used when
+ * a device wants to inform the rest of the network about some sort of
+ * reconfiguration such as a failover event or virtual machine
+ * migration.
+ */
+void __netdev_notify_peers(struct net_device *dev)
+{
+ ASSERT_RTNL();
+ call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
+ call_netdevice_notifiers(NETDEV_RESEND_IGMP, dev);
+}
+EXPORT_SYMBOL(__netdev_notify_peers);
+
/**
* netdev_notify_peers - notify network peers about existence of @dev
* @dev: network device
@@ -1469,8 +1488,7 @@ EXPORT_SYMBOL(netdev_state_change);
void netdev_notify_peers(struct net_device *dev)
{
rtnl_lock();
- call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, dev);
- call_netdevice_notifiers(NETDEV_RESEND_IGMP, dev);
+ __netdev_notify_peers(dev);
rtnl_unlock();
}
EXPORT_SYMBOL(netdev_notify_peers);
--
2.26.2