[net PatchV4] Octeontx2-vf: Fix max packet length errors

[net PatchV4] Octeontx2-vf: Fix max packet length errors

[Hariprasad Kelam]

Once driver submits the packets to the hardware, each packet
traverse through multiple transmit levels in the following
order:
	SMQ -> TL4 -> TL3 -> TL2 -> TL1

The SMQ supports configurable minimum and maximum packet sizes.
It enters to a hang state, if driver submits packets with
out of bound lengths.

To avoid the same, implement packet length validation before
submitting packets to the hardware. Increment tx_dropped counter
on failure.

Fixes: 3184fb5ba96e ("octeontx2-vf: Virtual function driver support")
Fixes: 22f858796758 ("octeontx2-pf: Add basic net_device_ops")
Fixes: 3ca6c4c882a7 ("octeontx2-pf: Add packet transmission support")
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
---
v4 * Update commit description with hardware limitation details.

v3 * Define driver specific counter for storing dropped packets.

v2 * Add the packet length check for rep dev
     Increment tx_dropped counter on failure

 .../net/ethernet/marvell/octeontx2/nic/otx2_common.c |  3 ++-
 .../net/ethernet/marvell/octeontx2/nic/otx2_common.h |  1 +
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c |  3 +++
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c | 10 ++++++++++
 drivers/net/ethernet/marvell/octeontx2/nic/rep.c     | 12 +++++++++++-
 drivers/net/ethernet/marvell/octeontx2/nic/rep.h     |  1 +
 6 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index 6b5c9536d26d..e480c8692baa 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -124,7 +124,8 @@ void otx2_get_dev_stats(struct otx2_nic *pfvf)
 			       dev_stats->rx_ucast_frames;
 
 	dev_stats->tx_bytes = OTX2_GET_TX_STATS(TX_OCTS);
-	dev_stats->tx_drops = OTX2_GET_TX_STATS(TX_DROP);
+	dev_stats->tx_drops = OTX2_GET_TX_STATS(TX_DROP) +
+			      dev_stats->tx_discards;
 	dev_stats->tx_bcast_frames = OTX2_GET_TX_STATS(TX_BCAST);
 	dev_stats->tx_mcast_frames = OTX2_GET_TX_STATS(TX_MCAST);
 	dev_stats->tx_ucast_frames = OTX2_GET_TX_STATS(TX_UCAST);
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
index ca0e6ab12ceb..a58c902eb75d 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
@@ -149,6 +149,7 @@ struct otx2_dev_stats {
 	u64 tx_bcast_frames;
 	u64 tx_mcast_frames;
 	u64 tx_drops;
+	u64 tx_discards;
 };
 
 /* Driver counted stats */
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
index db7c466fdc39..f9cf6a8f2f9b 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
@@ -2153,6 +2153,7 @@ static netdev_tx_t otx2_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
 	struct otx2_nic *pf = netdev_priv(netdev);
 	int qidx = skb_get_queue_mapping(skb);
+	struct otx2_dev_stats *dev_stats;
 	struct otx2_snd_queue *sq;
 	struct netdev_queue *txq;
 	int sq_idx;
@@ -2165,6 +2166,8 @@ static netdev_tx_t otx2_xmit(struct sk_buff *skb, struct net_device *netdev)
 	/* Check for minimum and maximum packet length */
 	if (skb->len <= ETH_HLEN ||
 	    (!skb_shinfo(skb)->gso_size && skb->len > pf->tx_max_pktlen)) {
+		dev_stats = &pf->hw.dev_stats;
+		dev_stats->tx_discards++;
 		dev_kfree_skb(skb);
 		return NETDEV_TX_OK;
 	}
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c
index 8a8b598bd389..3bb55e4a11d3 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c
@@ -391,9 +391,19 @@ static netdev_tx_t otx2vf_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
 	struct otx2_nic *vf = netdev_priv(netdev);
 	int qidx = skb_get_queue_mapping(skb);
+	struct otx2_dev_stats *dev_stats;
 	struct otx2_snd_queue *sq;
 	struct netdev_queue *txq;
 
+	/* Check for minimum and maximum packet length */
+	if (skb->len <= ETH_HLEN ||
+	    (!skb_shinfo(skb)->gso_size && skb->len > vf->tx_max_pktlen)) {
+		dev_stats = &vf->hw.dev_stats;
+		dev_stats->tx_discards++;
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
+
 	sq = &vf->qset.sq[qidx];
 	txq = netdev_get_tx_queue(netdev, qidx);
 
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/rep.c b/drivers/net/ethernet/marvell/octeontx2/nic/rep.c
index 2cd3da3b6843..d2412d027f6f 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/rep.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/rep.c
@@ -371,7 +371,7 @@ static void rvu_rep_get_stats(struct work_struct *work)
 	stats->rx_mcast_frames = rsp->rx.mcast;
 	stats->tx_bytes = rsp->tx.octs;
 	stats->tx_frames = rsp->tx.ucast + rsp->tx.bcast + rsp->tx.mcast;
-	stats->tx_drops = rsp->tx.drop;
+	stats->tx_drops = rsp->tx.drop + stats->tx_discards;
 exit:
 	mutex_unlock(&priv->mbox.lock);
 }
@@ -418,6 +418,16 @@ static netdev_tx_t rvu_rep_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct otx2_nic *pf = rep->mdev;
 	struct otx2_snd_queue *sq;
 	struct netdev_queue *txq;
+	struct rep_stats *stats;
+
+	/* Check for minimum and maximum packet length */
+	if (skb->len <= ETH_HLEN ||
+	    (!skb_shinfo(skb)->gso_size && skb->len > pf->tx_max_pktlen)) {
+		stats = &rep->stats;
+		stats->tx_discards++;
+		dev_kfree_skb(skb);
+		return NETDEV_TX_OK;
+	}
 
 	sq = &pf->qset.sq[rep->rep_id];
 	txq = netdev_get_tx_queue(dev, 0);
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/rep.h b/drivers/net/ethernet/marvell/octeontx2/nic/rep.h
index 38446b3e4f13..277615ed7174 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/rep.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/rep.h
@@ -27,6 +27,7 @@ struct rep_stats {
 	u64 tx_bytes;
 	u64 tx_frames;
 	u64 tx_drops;
+	u64 tx_discards;
 };
 
 struct rep_dev {
-- 
2.34.1

Re: [net PatchV4] Octeontx2-vf: Fix max packet length errors

[Jakub Kicinski]

On Thu, 24 Jul 2025 12:36:22 +0530 Hariprasad Kelam wrote:
> @@ -2165,6 +2166,8 @@ static netdev_tx_t otx2_xmit(struct sk_buff *skb, struct net_device *netdev)
>  	/* Check for minimum and maximum packet length */
>  	if (skb->len <= ETH_HLEN ||
>  	    (!skb_shinfo(skb)->gso_size && skb->len > pf->tx_max_pktlen)) {
> +		dev_stats = &pf->hw.dev_stats;
> +		dev_stats->tx_discards++;
>  		dev_kfree_skb(skb);
>  		return NETDEV_TX_OK;
>  	}

This is a multi-queue device and the counter is per device.
The counter should really be an atomic_long_t, to avoid races.
-- 
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