[SRU][F:linux-bluefield][PATCH 16/32] net/core: Introduce netdev_get_xmit_slave

[Daniel Jurgens]

From: Maor Gottlieb <maorg at mellanox.com>

BugLink: https://bugs.launchpad.net/bugs/1926994

Add new ndo to get the xmit slave of master device. The reference
counters are not incremented so the caller must be careful with locks.
User can ask to get the xmit slave assume all the slaves can
transmit by set all_slaves arg to true.

Signed-off-by: Maor Gottlieb <maorg at mellanox.com>
Reviewed-by: Jiri Pirko <jiri at mellanox.com>
Reviewed-by: David Ahern <dsahern at gmail.com>
Acked-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Saeed Mahameed <saeedm at mellanox.com>
(cherry picked from commit cff9f12b18915d957a2130885a00f8ab15cff7e4)
Signed-off-by: Daniel Jurgens <danielj at nvidia.com>
---
 include/linux/netdevice.h | 12 ++++++++++++
 net/core/dev.c            | 22 ++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index cc92e75..a6f261d 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1126,6 +1126,12 @@ struct dev_ifalias {
  * int (*ndo_del_slave)(struct net_device *dev, struct net_device *slave_dev);
  *	Called to release previously enslaved netdev.
  *
+ * struct net_device *(*ndo_get_xmit_slave)(struct net_device *dev,
+ *					    struct sk_buff *skb,
+ *					    bool all_slaves);
+ *	Get the xmit slave of master device. If all_slaves is true, function
+ *	assume all the slaves can transmit.
+ *
  *      Feature/offload setting functions.
  * netdev_features_t (*ndo_fix_features)(struct net_device *dev,
  *		netdev_features_t features);
@@ -1364,6 +1370,9 @@ struct net_device_ops {
 						 struct netlink_ext_ack *extack);
 	int			(*ndo_del_slave)(struct net_device *dev,
 						 struct net_device *slave_dev);
+	struct net_device*	(*ndo_get_xmit_slave)(struct net_device *dev,
+						      struct sk_buff *skb,
+						      bool all_slaves);
 	netdev_features_t	(*ndo_fix_features)(struct net_device *dev,
 						    netdev_features_t features);
 	int			(*ndo_set_features)(struct net_device *dev,
@@ -2652,6 +2661,9 @@ static inline void unregister_netdevice(struct net_device *dev)
 void synchronize_net(void);
 int init_dummy_netdev(struct net_device *dev);
 
+struct net_device *netdev_get_xmit_slave(struct net_device *dev,
+					 struct sk_buff *skb,
+					 bool all_slaves);
 struct net_device *dev_get_by_index(struct net *net, int ifindex);
 struct net_device *__dev_get_by_index(struct net *net, int ifindex);
 struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);
diff --git a/net/core/dev.c b/net/core/dev.c
index 9329716..1ebb338 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7527,6 +7527,28 @@ void netdev_bonding_info_change(struct net_device *dev,
 }
 EXPORT_SYMBOL(netdev_bonding_info_change);
 
+/**
+ * netdev_get_xmit_slave - Get the xmit slave of master device
+ * @skb: The packet
+ * @all_slaves: assume all the slaves are active
+ *
+ * The reference counters are not incremented so the caller must be
+ * careful with locks. The caller must hold RCU lock.
+ * %NULL is returned if no slave is found.
+ */
+
+struct net_device *netdev_get_xmit_slave(struct net_device *dev,
+					 struct sk_buff *skb,
+					 bool all_slaves)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+
+	if (!ops->ndo_get_xmit_slave)
+		return NULL;
+	return ops->ndo_get_xmit_slave(dev, skb, all_slaves);
+}
+EXPORT_SYMBOL(netdev_get_xmit_slave);
+
 static void netdev_adjacent_add_links(struct net_device *dev)
 {
 	struct netdev_adjacent *iter;
-- 
1.8.3.1