Store the RSS key inside struct igc_adapter and introduce the
igc_write_rss_key() helper function. This allows the driver to program
the RSSRK registers using a persistent RSS key, instead of using a
stack-local buffer in igc_setup_mrqc().

This is a preparation patch for adding RSS key get/set support in
subsequent changes, and no functional change is intended in this patch.

Signed-off-by: Kohei Enju <enjuk@amazon.com>
---
 drivers/net/ethernet/intel/igc/igc.h         |  3 +++
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 12 ++++++++++++
 drivers/net/ethernet/intel/igc/igc_main.c    |  6 ++----
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index a427f05814c1..dd159397d191 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -30,6 +30,7 @@ void igc_ethtool_set_ops(struct net_device *);
 
 #define MAX_ETYPE_FILTER		8
 #define IGC_RETA_SIZE			128
+#define IGC_RSS_KEY_SIZE		40
 
 /* SDP support */
 #define IGC_N_EXTTS	2
@@ -302,6 +303,7 @@ struct igc_adapter {
 	unsigned int nfc_rule_count;
 
 	u8 rss_indir_tbl[IGC_RETA_SIZE];
+	u8 rss_key[IGC_RSS_KEY_SIZE];
 
 	unsigned long link_check_timeout;
 	struct igc_info ei;
@@ -360,6 +362,7 @@ unsigned int igc_get_max_rss_queues(struct igc_adapter *adapter);
 void igc_set_flag_queue_pairs(struct igc_adapter *adapter,
 			      const u32 max_rss_queues);
 int igc_reinit_queues(struct igc_adapter *adapter);
+void igc_write_rss_key(struct igc_adapter *adapter);
 void igc_write_rss_indir_tbl(struct igc_adapter *adapter);
 bool igc_has_link(struct igc_adapter *adapter);
 void igc_reset(struct igc_adapter *adapter);
diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index ca93629b1d3a..f89c2cbaace0 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1456,6 +1456,18 @@ static int igc_ethtool_set_rxnfc(struct net_device *dev,
 	}
 }
 
+void igc_write_rss_key(struct igc_adapter *adapter)
+{
+	struct igc_hw *hw = &adapter->hw;
+	u32 val;
+	int i;
+
+	for (i = 0; i < IGC_RSS_KEY_SIZE / 4; i++) {
+		val = get_unaligned_le32(&adapter->rss_key[i * 4]);
+		wr32(IGC_RSSRK(i), val);
+	}
+}
+
 void igc_write_rss_indir_tbl(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 728d7ca5338b..1f0a601cbcef 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -778,11 +778,9 @@ static void igc_setup_mrqc(struct igc_adapter *adapter)
 	struct igc_hw *hw = &adapter->hw;
 	u32 j, num_rx_queues;
 	u32 mrqc, rxcsum;
-	u32 rss_key[10];
 
-	netdev_rss_key_fill(rss_key, sizeof(rss_key));
-	for (j = 0; j < 10; j++)
-		wr32(IGC_RSSRK(j), rss_key[j]);
+	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter->rss_key));
+	igc_write_rss_key(adapter);
 
 	num_rx_queues = adapter->rss_queues;
 
-- 
2.51.0