[PATCH net v2 1/2] net: stmmac: propagate FPE preemption-class mapping errors
From: Lorenzo Bianconi <hidden>
Date: 2026-09-09 14:26:40
Also in:
linux-arm-kernel, lkml
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
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 <redacted>
---
drivers/net/ethernet/stmicro/stmmac/hwif.h | 2 +-
drivers/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)
--
2.55.0