[dpdk-dev] [PATCH 2/3] net/sfc: use zero RSS channels as disabled RSS indicator

[Andrew Rybchenko <arybchenko@solarflare.com>]

Enabled RSS enables RSS hash computation and provision in pseudo header.
It still makes sense for applications even if only one Rx queue is used.

Fixes: 4ec1fc3ba881 ("net/sfc: add basic stubs for RSS support on driver attach")
Fixes: 088e17210a7a ("net/sfc: query RSS key and hash types config")
Fixes: 82faef507608 ("net/sfc: set RSS key and hash types config")
Fixes: af0d9317970c ("net/sfc: query RSS redirection table")
Fixes: 32bcfb0a50b1 ("net/sfc: update RSS redirection table")
Fixes: f5258439ee5d ("net/sfc: avoid failure on port start if Rx mode is rejected")

Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Andy Moreton <amoreton@solarflare.com>
---
 drivers/net/sfc/sfc_ethdev.c | 28 ++++++++++++++++++++--------
 drivers/net/sfc/sfc_rx.c     |  8 ++++----
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/drivers/net/sfc/sfc_ethdev.c b/drivers/net/sfc/sfc_ethdev.c
index 4f7b640..d117c29 100644
--- a/drivers/net/sfc/sfc_ethdev.c
+++ b/drivers/net/sfc/sfc_ethdev.c
@@ -1083,10 +1083,12 @@ sfc_dev_rss_hash_conf_get(struct rte_eth_dev *dev,
 {
 	struct sfc_adapter *sa = dev->data->dev_private;
 
-	if ((sa->rss_channels == 1) ||
-	    (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE))
+	if (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE)
 		return -ENOTSUP;
 
+	if (sa->rss_channels == 0)
+		return -EINVAL;
+
 	sfc_adapter_lock(sa);
 
 	/*
@@ -1113,12 +1115,16 @@ sfc_dev_rss_hash_update(struct rte_eth_dev *dev,
 	unsigned int efx_hash_types;
 	int rc = 0;
 
-	if ((sa->rss_channels == 1) ||
-	    (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE)) {
+	if (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE) {
 		sfc_err(sa, "RSS is not available");
 		return -ENOTSUP;
 	}
 
+	if (sa->rss_channels == 0) {
+		sfc_err(sa, "RSS is not configured");
+		return -EINVAL;
+	}
+
 	if ((rss_conf->rss_key != NULL) &&
 	    (rss_conf->rss_key_len != sizeof(sa->rss_key))) {
 		sfc_err(sa, "RSS key size is wrong (should be %lu)",
@@ -1175,10 +1181,12 @@ sfc_dev_rss_reta_query(struct rte_eth_dev *dev,
 	struct sfc_adapter *sa = dev->data->dev_private;
 	int entry;
 
-	if ((sa->rss_channels == 1) ||
-	    (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE))
+	if (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE)
 		return -ENOTSUP;
 
+	if (sa->rss_channels == 0)
+		return -EINVAL;
+
 	if (reta_size != EFX_RSS_TBL_SIZE)
 		return -EINVAL;
 
@@ -1208,12 +1216,16 @@ sfc_dev_rss_reta_update(struct rte_eth_dev *dev,
 	int rc;
 
 
-	if ((sa->rss_channels == 1) ||
-	    (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE)) {
+	if (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE) {
 		sfc_err(sa, "RSS is not available");
 		return -ENOTSUP;
 	}
 
+	if (sa->rss_channels == 0) {
+		sfc_err(sa, "RSS is not configured");
+		return -EINVAL;
+	}
+
 	if (reta_size != EFX_RSS_TBL_SIZE) {
 		sfc_err(sa, "RETA size is wrong (should be %u)",
 			EFX_RSS_TBL_SIZE);
diff --git a/drivers/net/sfc/sfc_rx.c b/drivers/net/sfc/sfc_rx.c
index 9f512d9..664b38d 100644
--- a/drivers/net/sfc/sfc_rx.c
+++ b/drivers/net/sfc/sfc_rx.c
@@ -577,7 +577,7 @@ sfc_rx_qflush(struct sfc_adapter *sa, unsigned int sw_index)
 static int
 sfc_rx_default_rxq_set_filter(struct sfc_adapter *sa, struct sfc_rxq *rxq)
 {
-	boolean_t rss = (sa->rss_channels > 1) ? B_TRUE : B_FALSE;
+	boolean_t rss = (sa->rss_channels > 0) ? B_TRUE : B_FALSE;
 	struct sfc_port *port = &sa->port;
 	int rc;
 
@@ -1052,7 +1052,7 @@ sfc_rx_rss_config(struct sfc_adapter *sa)
 	int rc = 0;
 
 #if EFSYS_OPT_RX_SCALE
-	if (sa->rss_channels > 1) {
+	if (sa->rss_channels > 0) {
 		rc = efx_rx_scale_mode_set(sa->nic, EFX_RX_HASHALG_TOEPLITZ,
 					   sa->rss_hash_types, B_TRUE);
 		if (rc != 0)
@@ -1289,9 +1289,9 @@ sfc_rx_configure(struct sfc_adapter *sa)
 
 #if EFSYS_OPT_RX_SCALE
 	sa->rss_channels = (dev_conf->rxmode.mq_mode == ETH_MQ_RX_RSS) ?
-			   MIN(sa->rxq_count, EFX_MAXRSS) : 1;
+			   MIN(sa->rxq_count, EFX_MAXRSS) : 0;
 
-	if (sa->rss_channels > 1) {
+	if (sa->rss_channels > 0) {
 		for (sw_index = 0; sw_index < EFX_RSS_TBL_SIZE; ++sw_index)
 			sa->rss_tbl[sw_index] = sw_index % sa->rss_channels;
 	}
-- 
2.7.4