On Fri, Sep 04, 2026 at 10:51:38AM +0000, Ciara Loftus wrote:
> Currently, ice_tx_queue_start() determines a queue's congestion domain by
> scanning vsi->info.tc_mapping[] for a matching traffic class range,
> rejecting the queue if no match is found.
>
> The Tx scheduler hierarchies only ever operate on a single traffic class,
> TC0, so every queue managed by a committed TM hierarchy always belongs
> to domain 0. The tc_mapping[] lookup doesn't account for this, and queues
> added after a TM hierarchy is committed can be incorrectly rejected.
>
> Fix this by skipping the lookup if a hierarchy has been committed as the
> domain is already known to be 0 in that case. Since TM does not support
> DCB's multi-TC queue layout, also reject queue start explicitly if DCB
> has configured more than one TC while a TM hierarchy is committed.
>
> Fixes: 02b71e570294 ("net/ice: support DCB")
> Cc: [email protected]
>
> Signed-off-by: Ciara Loftus <[email protected]>
> ---
> drivers/net/intel/ice/ice_ethdev.c | 4 ++++
> drivers/net/intel/ice/ice_ethdev.h | 2 ++
> drivers/net/intel/ice/ice_rxtx.c | 33 ++++++++++++++++++------------
> 3 files changed, 26 insertions(+), 13 deletions(-)
>
Did you hit this in testing, or was it just via code review or AI review?
Fix looks good anyway.
Acked-by: Bruce Richardson <[email protected]>
> diff --git a/drivers/net/intel/ice/ice_ethdev.c
> b/drivers/net/intel/ice/ice_ethdev.c
> index 76b8ff0a72e..fd148848d3c 100644
> --- a/drivers/net/intel/ice/ice_ethdev.c
> +++ b/drivers/net/intel/ice/ice_ethdev.c
> @@ -3963,6 +3963,8 @@ ice_dev_configure(struct rte_eth_dev *dev)
> ad->rx_func_type = ICE_RX_DEFAULT;
> ad->tx_func_type = ICE_TX_DEFAULT;
>
> + pf->dcb_num_tcs = 1;
> +
> if (dev->data->dev_conf.rxmode.mq_mode & RTE_ETH_MQ_RX_RSS_FLAG)
> dev->data->dev_conf.rxmode.offloads |=
> RTE_ETH_RX_OFFLOAD_RSS_HASH;
>
> @@ -3992,6 +3994,8 @@ ice_dev_configure(struct rte_eth_dev *dev)
> if (nb_tc_used < 0)
> return -EINVAL;
>
> + pf->dcb_num_tcs = nb_tc_used;
> +
> ctxt.info = vsi->info;
> if (rte_le_to_cpu_16(ctxt.info.mapping_flags) ==
> ICE_AQ_VSI_Q_MAP_NONCONTIG) {
> PMD_DRV_LOG(ERR, "VSI configured with non contiguous
> queues, DCB is not supported");
> diff --git a/drivers/net/intel/ice/ice_ethdev.h
> b/drivers/net/intel/ice/ice_ethdev.h
> index 7ee3ea8a709..5914454c7c2 100644
> --- a/drivers/net/intel/ice/ice_ethdev.h
> +++ b/drivers/net/intel/ice/ice_ethdev.h
> @@ -609,6 +609,8 @@ struct ice_pf {
> uint64_t rss_hf;
> struct ice_tm_conf tm_conf;
> uint16_t outer_ethertype;
> + /* Number of TCs requested, 1 if DCB not configured */
> + uint8_t dcb_num_tcs;
> /* lock prevent race condition between lsc interrupt handler
> * and link status update during dev_start.
> */
> diff --git a/drivers/net/intel/ice/ice_rxtx.c
> b/drivers/net/intel/ice/ice_rxtx.c
> index c4b5454c530..71f9155e588 100644
> --- a/drivers/net/intel/ice/ice_rxtx.c
> +++ b/drivers/net/intel/ice/ice_rxtx.c
> @@ -839,20 +839,27 @@ ice_tx_queue_start(struct rte_eth_dev *dev, uint16_t
> tx_queue_id)
> tx_ctx.legacy_int = 1; /* Legacy or Advanced Host Interface */
> tx_ctx.tsyn_ena = 1;
>
> - /* Mirror RXQ<->CGD association to TXQ<->CGD */
> - for (int i = 0; i < ICE_MAX_TRAFFIC_CLASS; i++) {
> - q_base = rte_le_to_cpu_16(vsi->info.tc_mapping[i]) &
> ICE_AQ_VSI_TC_Q_OFFSET_M;
> - q_range = 1 << ((rte_le_to_cpu_16(vsi->info.tc_mapping[i]) &
> - ICE_AQ_VSI_TC_Q_NUM_M) >> ICE_AQ_VSI_TC_Q_NUM_S);
> -
> - if (q_base <= tx_queue_id && tx_queue_id < q_base + q_range)
> - break;
> -
> - cgd_idx++;
> - }
> + if (!pf->tm_conf.committed) {
> + /* Mirror RXQ<->CGD association to TXQ<->CGD */
> + for (int i = 0; i < ICE_MAX_TRAFFIC_CLASS; i++) {
> + q_base = rte_le_to_cpu_16(vsi->info.tc_mapping[i]) &
> +
> ICE_AQ_VSI_TC_Q_OFFSET_M;
> + q_range = 1 <<
> ((rte_le_to_cpu_16(vsi->info.tc_mapping[i]) &
> + ICE_AQ_VSI_TC_Q_NUM_M) >>
> ICE_AQ_VSI_TC_Q_NUM_S);
> +
> + if (q_base <= tx_queue_id && tx_queue_id < q_base +
> q_range)
> + break;
>
> - if (cgd_idx >= ICE_MAX_TRAFFIC_CLASS) {
> - PMD_DRV_LOG(ERR, "Bad queue mapping configuration");
> + cgd_idx++;
> + }
> + if (cgd_idx >= ICE_MAX_TRAFFIC_CLASS) {
> + PMD_DRV_LOG(ERR, "Bad queue mapping configuration");
> + rte_free(txq_elem);
> + return -EINVAL;
> + }
> + } else if (pf->dcb_num_tcs > 1) {
> + /* TM only manages the TC0 scheduler subtree. */
> + PMD_DRV_LOG(ERR, "TM hierarchy is not supported together with
> multi-TC DCB");
> rte_free(txq_elem);
> return -EINVAL;
> }
> --
> 2.43.0
>
