[PATCH net] net: stmmac: hold runtime PM reference in setup_tc
From: Lorenzo Bianconi <hidden>
Date: 2026-08-24 17:46:48
Also in:
linux-arm-kernel
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
The qdisc offload callbacks invoked by stmmac_setup_tc() program
MTL/MAC registers, but they can be reached while the interface is down,
when stmmac_release() has dropped the runtime PM usage counter and the
device may be suspended with its clocks gated. Accessing the registers
in that state can trigger a bus error.
Hold a runtime PM reference while configuring the register-touching
qdisc offloads (mqprio, cbs and taprio) so the device is active, and its
clocks enabled, whenever the MTL/MAC registers are programmed.
The TC block callback stmmac_setup_tc_block_cb() programs the MTL/MAC
registers as well, but it runs asynchronously from stmmac_setup_tc(),
outside the runtime PM reference held there. Hold a runtime PM reference
for the whole stmmac_setup_tc_block_cb() call as well, covering the
cls_u32/cls_flower setup and the queue enable/disable accesses.
No reference is held for the TC_SETUP_BLOCK bookkeeping itself, the
TC_QUERY_CAPS query or the tc-etf path, since none of them touch the
registers synchronously. In particular the block bind/unbind must reach
flow_block_cb_setup_simple() even when the device is suspended, so the
driver never leaves a stale flow_block_cb on its block list.
Fixes: 1f705bc61aee ("net: stmmac: Add support for CBS QDISC")
Fixes: 4dbbe8dde848 ("net: stmmac: Add support for U32 TC filter using Flexible RX Parser")
Signed-off-by: Lorenzo Bianconi <redacted>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 34 ++++++++++++++++++++---
1 file changed, 30 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b2b7d0242dd3..4baf40fb01dc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c@@ -6392,9 +6392,13 @@ static int stmmac_setup_tc_block_cb(enum tc_setup_type type, void *type_data, void *cb_priv) { struct stmmac_priv *priv = cb_priv; - int ret = -EOPNOTSUPP; + int ret; if (!tc_cls_can_offload_and_chain0(priv->dev, type_data)) + return -EOPNOTSUPP; + + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) return ret; __stmmac_disable_all_queues(priv);
@@ -6411,6 +6415,8 @@ static int stmmac_setup_tc_block_cb(enum tc_setup_type type, void *type_data, } stmmac_enable_all_queues(priv); + pm_runtime_put(priv->device); + return ret; }
@@ -6420,26 +6426,46 @@ static int stmmac_setup_tc(struct net_device *ndev, enum tc_setup_type type, void *type_data) { struct stmmac_priv *priv = netdev_priv(ndev); + int ret; switch (type) { case TC_QUERY_CAPS: return stmmac_tc_query_caps(priv, priv, type_data); case TC_SETUP_QDISC_MQPRIO: - return stmmac_tc_setup_mqprio(priv, priv, type_data); + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) + return ret; + + ret = stmmac_tc_setup_mqprio(priv, priv, type_data); + break; case TC_SETUP_BLOCK: return flow_block_cb_setup_simple(type_data, &stmmac_block_cb_list, stmmac_setup_tc_block_cb, priv, priv, true); case TC_SETUP_QDISC_CBS: - return stmmac_tc_setup_cbs(priv, priv, type_data); + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) + return ret; + + ret = stmmac_tc_setup_cbs(priv, priv, type_data); + break; case TC_SETUP_QDISC_TAPRIO: - return stmmac_tc_setup_taprio(priv, priv, type_data); + ret = pm_runtime_resume_and_get(priv->device); + if (ret < 0) + return ret; + + ret = stmmac_tc_setup_taprio(priv, priv, type_data); + break; case TC_SETUP_QDISC_ETF: return stmmac_tc_setup_etf(priv, priv, type_data); default: return -EOPNOTSUPP; } + + pm_runtime_put(priv->device); + + return ret; } static u16 stmmac_select_queue(struct net_device *dev, struct sk_buff *skb,
--- base-commit: 7cbfb180945ce529608e4d4e24a6d483699fab1e change-id: 20260824-stmmac-setup-tc-enable-pm-149aa563d797 Best regards, -- Lorenzo Bianconi [off-list ref]