From 25102893e409bc02761ab82dbcfa092006404790 Mon Sep 17 00:00:00 2001 From: Tan Tee Min Date: Fri, 9 Jun 2023 11:28:42 +0800 Subject: [PATCH] igc: Include the length/type field and VLAN tag in queueMaxSDU IEEE 802.1Q does not have clear definitions of what constitutes an SDU (Service Data Unit), but IEEE Std 802.3 clause 3.1.2 does define the MAC service primitives and clause 3.2.7 does define the MAC Client Data for Q-tagged frames. It shows that the mac_service_data_unit (MSDU) does NOT contain the preamble, destination and source address, or FCS. The MSDU does contain the length/type field, MAC client data, VLAN tag and any padding data (prior to the FCS). Thus, the maximum 802.3 frame size that is allowed to be transmitted should be QueueMaxSDU (MSDU) + 16 (6 byte SA + 6 byte DA + 4 byte FCS). Fixes: 92a0dcb8427d ("igc: offload queue max SDU from tc-taprio") Signed-off-by: Tan Tee Min Reviewed-by: Muhammad Husaini Zulkifli Tested-by: Naama Meir Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/igc/igc_main.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index e5bfc40006584..281a0e35b9d1d 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -1575,16 +1575,9 @@ done: if (adapter->qbv_transition || tx_ring->oper_gate_closed) goto out_drop; - if (tx_ring->max_sdu > 0) { - u32 max_sdu = 0; - - max_sdu = tx_ring->max_sdu + - (skb_vlan_tagged(first->skb) ? VLAN_HLEN : 0); - - if (first->bytecount > max_sdu) { - adapter->stats.txdrop++; - goto out_drop; - } + if (tx_ring->max_sdu > 0 && first->bytecount > tx_ring->max_sdu) { + adapter->stats.txdrop++; + goto out_drop; } if (unlikely(test_bit(IGC_RING_FLAG_TX_HWTSTAMP, &tx_ring->flags) && @@ -6231,7 +6224,7 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter, struct net_device *dev = adapter->netdev; if (qopt->max_sdu[i]) - ring->max_sdu = qopt->max_sdu[i] + dev->hard_header_len; + ring->max_sdu = qopt->max_sdu[i] + dev->hard_header_len - ETH_TLEN; else ring->max_sdu = 0; } -- 2.30.2