[PATCH v4 net-next 1/9] net: ethtool: create and export ethtool_dev_mm_supported()

[Vladimir Oltean]

Create a wrapper over __ethtool_dev_mm_supported() which also calls
ethnl_ops_begin() and ethnl_ops_complete(). It can be used by other code
layers, such as tc, to make sure that preemptible TCs are supported
(this is true if an underlying MAC Merge layer exists).

Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Ferenc Fejes <fejes@xxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
---
v3->v4: none
v2->v3: none
v1->v2:
- don't touch net/sched/sch_mqprio.c in this patch
- add missing EXPORT_SYMBOL_GPL(ethtool_dev_mm_supported)

 include/linux/ethtool_netlink.h |  6 ++++++
 net/ethtool/mm.c                | 23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/include/linux/ethtool_netlink.h b/include/linux/ethtool_netlink.h
index 17003b385756..fae0dfb9a9c8 100644
--- a/include/linux/ethtool_netlink.h
+++ b/include/linux/ethtool_netlink.h
@@ -39,6 +39,7 @@ void ethtool_aggregate_pause_stats(struct net_device *dev,
 				   struct ethtool_pause_stats *pause_stats);
 void ethtool_aggregate_rmon_stats(struct net_device *dev,
 				  struct ethtool_rmon_stats *rmon_stats);
+bool ethtool_dev_mm_supported(struct net_device *dev);
 
 #else
 static inline int ethnl_cable_test_alloc(struct phy_device *phydev, u8 cmd)
@@ -112,5 +113,10 @@ ethtool_aggregate_rmon_stats(struct net_device *dev,
 {
 }
 
+static inline bool ethtool_dev_mm_supported(struct net_device *dev)
+{
+	return false;
+}
+
 #endif /* IS_ENABLED(CONFIG_ETHTOOL_NETLINK) */
 #endif /* _LINUX_ETHTOOL_NETLINK_H_ */
diff --git a/net/ethtool/mm.c b/net/ethtool/mm.c
index fce3cc2734f9..e00d7d5cea7e 100644
--- a/net/ethtool/mm.c
+++ b/net/ethtool/mm.c
@@ -249,3 +249,26 @@ bool __ethtool_dev_mm_supported(struct net_device *dev)
 
 	return !ret;
 }
+
+bool ethtool_dev_mm_supported(struct net_device *dev)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	bool supported;
+	int ret;
+
+	ASSERT_RTNL();
+
+	if (!ops)
+		return false;
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		return false;
+
+	supported = __ethtool_dev_mm_supported(dev);
+
+	ethnl_ops_complete(dev);
+
+	return supported;
+}
+EXPORT_SYMBOL_GPL(ethtool_dev_mm_supported);
-- 
2.34.1