[PATCH net v3 2/2] eth: fbnic: Publish real queue counts

[Björn Töpel]

fbnic exposes more queues than it configures until open, including
after ethtool -L while down. A memory provider can bind to an
unconfigured queue.

Publish the selected counts at probe and on offline channel changes.

Sashiko flagged the mismatch by code inspection; it was not reproduced
on physical hardware. Tested with fbnic QEMU on Debian sid: offline
ethtool -L changed RX/TX queues from 2 to 1 to 3. Reopening passed
DHCP and ping. Network selftests were not run.

Fixes: da43127a8edc ("eth: fbnic: support queue ops / zero-copy Rx")
Reported-by: Sashiko <netdev-bot+sashiko@xxxxxxxxxx>
Link: https://lore.kernel.org/netdev/178915061000.219967.7726187707862333281@xxxxxxxxxx/
Signed-off-by: Björn Töpel <bjorn@xxxxxxxxxx>
---
 .../net/ethernet/meta/fbnic/fbnic_ethtool.c   |  7 +++++
 .../net/ethernet/meta/fbnic/fbnic_netdev.c    | 29 +++++++++++++------
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
index 76e9a545bb16..b96354e56517 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
@@ -1631,6 +1631,13 @@ static int fbnic_set_channels(struct net_device *netdev,
 		return -EINVAL;
 
 	if (!netif_running(netdev)) {
+		unsigned int rxq = ch->rx_count + ch->combined_count;
+		unsigned int txq = ch->tx_count + ch->combined_count;
+
+		err = netif_set_real_num_queues(netdev, txq, rxq);
+		if (err)
+			return err;
+
 		fbnic_set_queues(fbn, ch, max_napis);
 		fbnic_reset_indir_tbl(fbn);
 		return 0;
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
index d1ed29312d54..1e16e10f3505 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
@@ -709,11 +709,12 @@ static const struct netdev_stat_ops fbnic_stat_ops = {
 	.get_base_stats		= fbnic_get_base_stats,
 };
 
-static void fbnic_reset_queues(struct fbnic_net *fbn,
-			       unsigned int tx, unsigned int rx)
+static int fbnic_reset_queues(struct fbnic_net *fbn,
+			      unsigned int tx, unsigned int rx)
 {
 	struct fbnic_dev *fbd = fbn->fbd;
 	unsigned int max_napis;
+	int err;
 
 	max_napis = fbd->num_irqs - FBNIC_NON_NAPI_VECTORS;
 
@@ -724,6 +725,14 @@ static void fbnic_reset_queues(struct fbnic_net *fbn,
 	fbn->num_rx_queues = rx;
 
 	fbn->num_napi = max(tx, rx);
+
+	err = netif_set_real_num_queues(fbn->netdev, tx, rx);
+	if (err)
+		return err;
+
+	fbnic_reset_indir_tbl(fbn);
+
+	return 0;
 }
 
 /**
@@ -792,9 +801,9 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)
 	if (default_queues > fbd->max_num_queues)
 		default_queues = fbd->max_num_queues;
 
-	fbnic_reset_queues(fbn, default_queues, default_queues);
+	if (fbnic_reset_queues(fbn, default_queues, default_queues))
+		goto err_free_netdev;
 
-	fbnic_reset_indir_tbl(fbn);
 	fbnic_rss_key_fill(fbn->rss_key);
 	fbnic_rss_init_en_mask(fbn);
 
@@ -839,13 +848,15 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)
 
 	netif_tx_stop_all_queues(netdev);
 
-	if (fbnic_phylink_create(netdev)) {
-		free_netdev(netdev);
-		fbd->netdev = NULL;
-		return NULL;
-	}
+	if (fbnic_phylink_create(netdev))
+		goto err_free_netdev;
 
 	return netdev;
+
+err_free_netdev:
+	free_netdev(netdev);
+	fbd->netdev = NULL;
+	return NULL;
 }
 
 static int fbnic_dsn_to_mac_addr(u64 dsn, char *addr)
-- 
2.55.0