From 90e4b849dfa6fc8e6c050bcfe1b331b69c015d28 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Fri, 11 Sep 2026 10:58:29 +0200 Subject: [PATCH 1/2] net: stmmac: propagate FPE preemption-class mapping errors stmmac_fpe_map_preemption_class() dispatches through the stmmac_do_void_callback() helper, which forces the callback's return value to 0 whenever the op pointer is populated. As a result the -EINVAL returned by dwmac5_fpe_map_preemption_class() (e.g. when a preemptible TC owns more than one TXQ under SP scheduling) is silently swallowed by every caller. Switch the dispatch macro to stmmac_do_callback() so the callback's real result is propagated, and honour it in the taprio and mqprio qdisc offload. Note that the taprio "if (ret)" check in tc_taprio_configure() used to be dead code and now becomes live: a preemptible TC spanning more than one TXQ under SP scheduling cannot be programmed in hardware, so a taprio or mqprio configuration that previously returned success while leaving the preemption-class register unprogrammed now fails with -EINVAL. For taprio, the failure also runs the disable path, tearing down the schedule that was just installed; this is the intended behaviour. Fixes: 195e4f409a40 ("net: stmmac: support fp parameter of tc-mqprio") Signed-off-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260911-stmmac-tc_setup_dwmac510_mqprio-error-path-v3-1-a76b1e2547c1@oss.qualcomm.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/stmicro/stmmac/hwif.h | 2 +- .../net/ethernet/stmicro/stmmac/stmmac_tc.c | 19 +++++++++---------- 2 files changed, 10 insertions(+), 11 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..5398616fcdfe 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 @@ static int tc_taprio_configure(struct stmmac_priv *priv, 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, @@ -1237,14 +1237,15 @@ 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_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, @@ -1257,10 +1258,8 @@ static int tc_setup_dwmac510_mqprio(struct stmmac_priv *priv, u32 num_tc = qopt->num_tc; int err; - if (!num_tc) { - stmmac_reset_tc_mqprio(ndev, extack); - return 0; - } + if (!num_tc) + return stmmac_reset_tc_mqprio(ndev, extack); err = netdev_set_num_tc(ndev, num_tc); if (err) From 02fffd1939f6b45892f61822459953ce95e42948 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Fri, 11 Sep 2026 10:58:30 +0200 Subject: [PATCH 2/2] net: stmmac: preserve real_num_tx_queues on mqprio setup failure With the FPE preemption-class mapping error now propagated from stmmac_fpe_map_preemption_class(), tc_setup_dwmac510_mqprio() can fail on the mapping step. The error path used to call stmmac_reset_tc_mqprio(), which resets the number of real TX queues to priv->plat->tx_queues_to_use (the platform maximum), overwriting the value that was active before the offload was attempted (for example a lower count left over from a previous mqprio configuration). The issue can be triggered using the following configuration: # First mqprio config lowers the hw queue count below the platform # default (e.g. 8 TX queues). $tc qdisc add dev eth0 root handle 1: mqprio queues 2@0 2@2 # Replace mqprio configuration with a second one that fails FPE # preemption-class mapping. stmmac driver resets the real_num_tx_queues # to the platform maximum, losing the previous configuration. $tc qdisc replace dev eth0 root handle 2: mqprio queues 2@0 2@2 fp E P Save ndev->real_num_tx_queues before lowering it and restore it, together with the TC-to-queue and priority-to-TC mappings, when the FPE preemption-class mapping fails, instead of resetting the queue count to the platform maximum. Note that a failed setup makes the qdisc layer run mqprio_destroy() on the new qdisc. Because priv->hw_offload is only assigned after ndo_setup_tc() succeeds, mqprio_destroy() calls netdev_set_num_tc(dev, 0), so dev->num_tc ends up 0 regardless of the driver-side restore and the previous qdisc is not reactivated. The restore is still needed to keep real_num_tx_queues and to avoid leaving the failed configuration's TC-to-queue and priority-to-TC mappings in place. Fixes: 195e4f409a40 ("net: stmmac: support fp parameter of tc-mqprio") Signed-off-by: Lorenzo Bianconi Link: https://patch.msgid.link/20260911-stmmac-tc_setup_dwmac510_mqprio-error-path-v3-2-a76b1e2547c1@oss.qualcomm.com Signed-off-by: Jakub Kicinski --- .../net/ethernet/stmicro/stmmac/stmmac_tc.c | 80 ++++++++++++++----- 1 file changed, 61 insertions(+), 19 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c index 5398616fcdfe..42a00446e9b4 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c @@ -1237,6 +1237,30 @@ static int tc_query_caps(struct stmmac_priv *priv, } } +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) { @@ -1251,43 +1275,61 @@ static int stmmac_reset_tc_mqprio(struct net_device *ndev, 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; + u8 ndev_prio_tc_map[TC_BITMASK + 1]; + int i, err, ndev_ntc; - if (!num_tc) + if (!qopt->num_tc) return stmmac_reset_tc_mqprio(ndev, extack); - err = netdev_set_num_tc(ndev, num_tc); - if (err) - return err; + if (qopt->num_tc > ARRAY_SIZE(tc_to_txq)) + return -EINVAL; - for (u32 tc = 0; tc < num_tc; tc++) { - offset = qopt->offset[tc]; - count = qopt->count[tc]; - num_stack_tx_queues += count; + /* 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]); - err = netdev_set_tc_queue(ndev, tc, count, offset); - if (err) - goto err_reset_tc; + 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 err_reset_tc; + 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 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; }