diff mbox series

[net-next,1/3] net: core: introduce __netdev_notify_peers

Message ID 20201209061811.48524-2-ljp@linux.ibm.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series lockless version of netdev_notify_peers | expand

Checks

Context Check Description
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netdev/fixes_present success Link
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netdev/tree_selection success Clearly marked for net-next
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netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 7660 this patch: 7660
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 41 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 7770 this patch: 7770
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Lijun Pan Dec. 9, 2020, 6:18 a.m. UTC 
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>
---
 include/linux/netdevice.h |  1 +
 net/core/dev.c            | 22 ++++++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)
diff mbox series

Patch

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 ce8fea2e2788..6aa1de86a2e0 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);