Merge branch 'net-stmmac-restore-previous-state-if-tc_setup_dwmac510_mqprio-fails'

Lorenzo Bianconi says:

====================
net: stmmac: restore previous state if tc_setup_dwmac510_mqprio() fails

Restore previous mqprio qdisc configuration if
tc_setup_dwmac510_mqprio() fails running the following configuration:

  $tc qdisc add dev eth0 root handle 1: mqprio queues 2@0 2@2
  $tc qdisc replace dev eth0 root handle 2: mqprio queues 2@0 2@2 fp E P

Propagate FPE preemption-class mapping errors in
tc_setup_dwmac510_mqprio() and tc_taprio_configure().
====================

Link: https://patch.msgid.link/20260911-stmmac-tc_setup_dwmac510_mqprio-error-path-v3-0-a76b1e2547c1@oss.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 71 insertions, 30 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 04dafec021b4..9314bcb85c22 100644
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -494,7 +494,7 @@ struct stmmac_ops {
 #define stmmac_set_arp_offload(__priv, __args...) \
 	stmmac_do_void_callback(__priv, mac, set_arp_offload, __args)
 #define stmmac_fpe_map_preemption_class(__priv, __args...) \
-	stmmac_do_void_callback(__priv, mac, fpe_map_preemption_class, __args)
+	stmmac_do_callback(__priv, mac, fpe_map_preemption_class, __args)
 
 /* PTP and HW Timer helpers */
 struct stmmac_hwtimestamp {
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
index 14cabe76e53e..42a00446e9b4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c
@@ -970,7 +970,7 @@ static int tc_taprio_configure(struct stmmac_priv *priv,
 	struct netlink_ext_ack *extack = qopt->mqprio.extack;
 	struct timespec64 time, current_time, qopt_time;
 	ktime_t current_time_ns;
-	int i, ret = 0;
+	int err, i, ret = 0;
 	u64 ctr;
 
 	if (qopt->base_time < 0)
@@ -1120,9 +1120,9 @@ disable:
 		mutex_unlock(&priv->est_lock);
 	}
 
-	stmmac_fpe_map_preemption_class(priv, priv->dev, extack, 0);
+	err = stmmac_fpe_map_preemption_class(priv, priv->dev, extack, 0);
 
-	return ret;
+	return qopt->cmd == TAPRIO_CMD_DESTROY ? err : ret;
 }
 
 static void tc_taprio_stats(struct stmmac_priv *priv,
@@ -1237,58 +1237,99 @@ static int tc_query_caps(struct stmmac_priv *priv,
 	}
 }
 
-static void stmmac_reset_tc_mqprio(struct net_device *ndev,
-				   struct netlink_ext_ack *extack)
+static int stmmac_set_ndev_tcs(struct net_device *ndev, u8 ntc,
+			       struct netdev_tc_txq *tc_to_txq)
+{
+	int i, err;
+
+	netdev_reset_tc(ndev);
+	if (!ntc)
+		return 0;
+
+	err = netdev_set_num_tc(ndev, ntc);
+	if (err)
+		return err;
+
+	for (i = 0; i < ntc; i++) {
+		u16 count, offset;
+
+		count = tc_to_txq[i].count;
+		offset = tc_to_txq[i].offset;
+		netdev_set_tc_queue(ndev, i, count, offset);
+	}
+
+	return 0;
+}
+
+static int stmmac_reset_tc_mqprio(struct net_device *ndev,
+				  struct netlink_ext_ack *extack)
 {
 	struct stmmac_priv *priv = netdev_priv(ndev);
 
 	netdev_reset_tc(ndev);
 	netif_set_real_num_tx_queues(ndev, priv->plat->tx_queues_to_use);
-	stmmac_fpe_map_preemption_class(priv, ndev, extack, 0);
+
+	return stmmac_fpe_map_preemption_class(priv, ndev, extack, 0);
 }
 
 static int tc_setup_dwmac510_mqprio(struct stmmac_priv *priv,
 				    struct tc_mqprio_qopt_offload *mqprio)
 {
+	unsigned int ndev_num_tx_queues, num_tx_queues = 0;
+	struct netdev_tc_txq ndev_tc_to_txq[TC_MAX_QUEUE];
+	struct netdev_tc_txq tc_to_txq[TC_MAX_QUEUE] = {};
 	struct netlink_ext_ack *extack = mqprio->extack;
 	struct tc_mqprio_qopt *qopt = &mqprio->qopt;
-	u32 offset, count, num_stack_tx_queues = 0;
 	struct net_device *ndev = priv->dev;
-	u32 num_tc = qopt->num_tc;
-	int err;
-
-	if (!num_tc) {
-		stmmac_reset_tc_mqprio(ndev, extack);
-		return 0;
-	}
+	u8 ndev_prio_tc_map[TC_BITMASK + 1];
+	int i, err, ndev_ntc;
 
-	err = netdev_set_num_tc(ndev, num_tc);
-	if (err)
-		return err;
+	if (!qopt->num_tc)
+		return stmmac_reset_tc_mqprio(ndev, extack);
 
-	for (u32 tc = 0; tc < num_tc; tc++) {
-		offset = qopt->offset[tc];
-		count = qopt->count[tc];
-		num_stack_tx_queues += count;
+	if (qopt->num_tc > ARRAY_SIZE(tc_to_txq))
+		return -EINVAL;
 
-		err = netdev_set_tc_queue(ndev, tc, count, offset);
-		if (err)
-			goto err_reset_tc;
+	/* save current tc values for reset */
+	ndev_ntc = netdev_get_num_tc(ndev);
+	for (i = 0; i < ARRAY_SIZE(ndev->tc_to_txq); i++)
+		ndev_tc_to_txq[i].combined =
+			READ_ONCE(ndev->tc_to_txq[i].combined);
+	for (i = 0; i < ARRAY_SIZE(ndev_prio_tc_map); i++)
+		ndev_prio_tc_map[i] = READ_ONCE(ndev->prio_tc_map[i]);
+
+	for (i = 0; i < qopt->num_tc; i++) {
+		tc_to_txq[i] = (struct netdev_tc_txq) {
+			.count = qopt->count[i],
+			.offset = qopt->offset[i],
+		};
+		num_tx_queues += qopt->count[i];
 	}
 
-	err = netif_set_real_num_tx_queues(ndev, num_stack_tx_queues);
+	err = stmmac_set_ndev_tcs(ndev, qopt->num_tc, tc_to_txq);
+	if (err)
+		goto error_reset_tc;
+
+	ndev_num_tx_queues = ndev->real_num_tx_queues;
+	err = netif_set_real_num_tx_queues(ndev, num_tx_queues);
 	if (err)
-		goto err_reset_tc;
+		goto error_reset_tc;
 
 	err = stmmac_fpe_map_preemption_class(priv, ndev, extack,
 					      mqprio->preemptible_tcs);
 	if (err)
-		goto err_reset_tc;
+		goto error_reset_num_tx_queues;
 
 	return 0;
 
-err_reset_tc:
-	stmmac_reset_tc_mqprio(ndev, extack);
+error_reset_num_tx_queues:
+	if (netif_set_real_num_tx_queues(ndev, ndev_num_tx_queues))
+		netdev_warn(ndev, "Failed to restore %u TX queues\n",
+			    ndev_num_tx_queues);
+error_reset_tc:
+	stmmac_set_ndev_tcs(ndev, ndev_ntc, ndev_tc_to_txq);
+	for (i = 0; i < ARRAY_SIZE(ndev_prio_tc_map); i++)
+		netdev_set_prio_tc_map(ndev, i, ndev_prio_tc_map[i]);
 
 	return err;
 }