[PATCH iwl-next v2 3/3] igb: allow configuring RSS key via ethtool set_rxfh

[Takashi Kozu <takkozu@amazon.com>]

Change igb_set_rxfh() to accept and save a userspace-provided
RSS key. When a key is provided, store it in the adapter and write the
E1000 registers accordingly.

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

Tested-by: Kohei Enju <enjuk@amazon.com>
Signed-off-by: Takashi Kozu <takkozu@amazon.com>
---
 drivers/net/ethernet/intel/igb/igb.h         |  1 +
 drivers/net/ethernet/intel/igb/igb_ethtool.c | 49 +++++++++++---------
 drivers/net/ethernet/intel/igb/igb_main.c    |  3 +-
 3 files changed, 30 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 8c9b02058cec..2509ec30acf3 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -657,6 +657,7 @@ struct igb_adapter {
 	u32 rss_indir_tbl_init;
 	u8 rss_indir_tbl[IGB_RETA_SIZE];
 	u8 rss_key[IGB_RSS_KEY_SIZE];
+	bool has_user_rss_key;
 
 	unsigned long link_check_timeout;
 	int copper_tries;
diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index 2953d079ebae..ac045fbebade 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -3345,35 +3345,40 @@ static int igb_set_rxfh(struct net_device *netdev,
 	u32 num_queues;
 
 	/* 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;
 
-	switch (hw->mac.type) {
-	case e1000_82576:
-		/* 82576 supports 2 RSS queues for SR-IOV */
-		if (adapter->vfs_allocated_count)
-			num_queues = 2;
-		break;
-	default:
-		break;
-	}
+		switch (hw->mac.type) {
+		case e1000_82576:
+			/* 82576 supports 2 RSS queues for SR-IOV */
+			if (adapter->vfs_allocated_count)
+				num_queues = 2;
+			break;
+		default:
+			break;
+		}
 
-	/* Verify user input. */
-	for (i = 0; i < IGB_RETA_SIZE; i++)
-		if (rxfh->indir[i] >= num_queues)
-			return -EINVAL;
+		/* Verify user input. */
+		for (i = 0; i < IGB_RETA_SIZE; i++)
+			if (rxfh->indir[i] >= num_queues)
+				return -EINVAL;
 
 
-	for (i = 0; i < IGB_RETA_SIZE; i++)
-		adapter->rss_indir_tbl[i] = rxfh->indir[i];
+		for (i = 0; i < IGB_RETA_SIZE; i++)
+			adapter->rss_indir_tbl[i] = rxfh->indir[i];
+
+		igb_write_rss_indir_tbl(adapter);
+	}
 
-	igb_write_rss_indir_tbl(adapter);
+	if (rxfh->key) {
+		adapter->has_user_rss_key = true;
+		memcpy(adapter->rss_key, rxfh->key, sizeof(adapter->rss_key));
+		igb_write_rss_key(adapter);
+	}
 
 	return 0;
 }
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index da0f550de605..d42b3750f0b1 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4526,7 +4526,8 @@ static void igb_setup_mrqc(struct igb_adapter *adapter)
 	u32 mrqc, rxcsum;
 	u32 j, num_rx_queues;
 
-	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));
 	igb_write_rss_key(adapter);
 
 	num_rx_queues = adapter->rss_queues;
-- 
2.52.0