[PATCH 4.9 41/88] net: ena: make ena rxfh support ETH_RSS_HASH_NO_CHANGE

[Greg Kroah-Hartman]

From: Arthur Kiyanovski <akiyano@xxxxxxxxxx>

commit 470793a78ce344bd53d31e0c2d537f71ba957547 upstream.

As the name suggests ETH_RSS_HASH_NO_CHANGE is received upon changing
the key or indirection table using ethtool while keeping the same hash
function.

Also add a function for retrieving the current hash function from
the ena-com layer.

Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Sameeh Jubran <sameehj@xxxxxxxxxx>
Signed-off-by: Saeed Bshara <saeedb@xxxxxxxxxx>
Signed-off-by: Arthur Kiyanovski <akiyano@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/ethernet/amazon/ena/ena_com.c     |    5 +++++
 drivers/net/ethernet/amazon/ena/ena_com.h     |    8 ++++++++
 drivers/net/ethernet/amazon/ena/ena_ethtool.c |    3 +++
 3 files changed, 16 insertions(+)

--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -857,6 +857,11 @@ static void ena_com_hash_key_fill_defaul
 	hash_key->keys_num = sizeof(hash_key->key) / sizeof(u32);
 }
 
+int ena_com_get_current_hash_function(struct ena_com_dev *ena_dev)
+{
+	return ena_dev->rss.hash_func;
+}
+
 static int ena_com_hash_key_allocate(struct ena_com_dev *ena_dev)
 {
 	struct ena_rss *rss = &ena_dev->rss;
--- a/drivers/net/ethernet/amazon/ena/ena_com.h
+++ b/drivers/net/ethernet/amazon/ena/ena_com.h
@@ -623,6 +623,14 @@ int ena_com_rss_init(struct ena_com_dev
  */
 void ena_com_rss_destroy(struct ena_com_dev *ena_dev);
 
+/* ena_com_get_current_hash_function - Get RSS hash function
+ * @ena_dev: ENA communication layer struct
+ *
+ * Return the current hash function.
+ * @return: 0 or one of the ena_admin_hash_functions values.
+ */
+int ena_com_get_current_hash_function(struct ena_com_dev *ena_dev);
+
 /* ena_com_fill_hash_function - Fill RSS hash function
  * @ena_dev: ENA communication layer struct
  * @func: The hash function (Toeplitz or crc)
--- a/drivers/net/ethernet/amazon/ena/ena_ethtool.c
+++ b/drivers/net/ethernet/amazon/ena/ena_ethtool.c
@@ -751,6 +751,9 @@ static int ena_set_rxfh(struct net_devic
 	}
 
 	switch (hfunc) {
+	case ETH_RSS_HASH_NO_CHANGE:
+		func = ena_com_get_current_hash_function(ena_dev);
+		break;
 	case ETH_RSS_HASH_TOP:
 		func = ENA_ADMIN_TOEPLITZ;
 		break;