[Intel-wired-lan] [PATCH iwl-next v1 3/3] igc: allow configuring RSS key via ethtool set_rxfh

[Kohei Enju <enjuk@amazon.com>]

Change igc_ethtool_set_rxfh() to accept and save a userspace-provided
RSS key. When a key is provided, store it in the adapter and write the
RSSRK registers accordingly.

This can be tested using `ethtool -X <dev> hkey <key>`.

Signed-off-by: Kohei Enju <enjuk@amazon.com>
---
 drivers/net/ethernet/intel/igc/igc.h         |  1 +
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 31 ++++++++++++--------
 drivers/net/ethernet/intel/igc/igc_main.c    |  3 +-
 3 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index dd159397d191..c894a5a99fc0 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -304,6 +304,7 @@ struct igc_adapter {
 
 	u8 rss_indir_tbl[IGC_RETA_SIZE];
 	u8 rss_key[IGC_RSS_KEY_SIZE];
+	bool has_user_rss_key;
 
 	unsigned long link_check_timeout;
 	struct igc_info ei;
diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 0482e590bc5a..64eac1ccb3ff 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1527,24 +1527,29 @@ static int igc_ethtool_set_rxfh(struct net_device *netdev,
 	int i;
 
 	/* We do not allow change in unsupported parameters */
-	if (rxfh->key ||
-	    (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
-	     rxfh->hfunc != ETH_RSS_HASH_TOP))
+	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
+	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
-	if (!rxfh->indir)
-		return 0;
 
-	num_queues = adapter->rss_queues;
+	if (rxfh->indir) {
+		num_queues = adapter->rss_queues;
 
-	/* Verify user input. */
-	for (i = 0; i < IGC_RETA_SIZE; i++)
-		if (rxfh->indir[i] >= num_queues)
-			return -EINVAL;
+		/* Verify user input. */
+		for (i = 0; i < IGC_RETA_SIZE; i++)
+			if (rxfh->indir[i] >= num_queues)
+				return -EINVAL;
 
-	for (i = 0; i < IGC_RETA_SIZE; i++)
-		adapter->rss_indir_tbl[i] = rxfh->indir[i];
+		for (i = 0; i < IGC_RETA_SIZE; i++)
+			adapter->rss_indir_tbl[i] = rxfh->indir[i];
 
-	igc_write_rss_indir_tbl(adapter);
+		igc_write_rss_indir_tbl(adapter);
+	}
+
+	if (rxfh->key) {
+		adapter->has_user_rss_key = true;
+		memcpy(adapter->rss_key, rxfh->key, sizeof(adapter->rss_key));
+		igc_write_rss_key(adapter);
+	}
 
 	return 0;
 }
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 1f0a601cbcef..e977661bed2f 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -779,7 +779,8 @@ static void igc_setup_mrqc(struct igc_adapter *adapter)
 	u32 j, num_rx_queues;
 	u32 mrqc, rxcsum;
 
-	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter->rss_key));
+	if (!adapter->has_user_rss_key)
+		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