The current mana_tx_timeout() handler unconditionally schedules a full port queue reset (detach/attach) whenever the TX watchdog fires. This is unnecessary for transient stalls where completions are simply delayed or an interrupt was missed. Implement a graduated recovery approach: on the first TX timeout (or when the previous timeout was more than 2 minutes ago), schedule NAPI on the stalled queue's TX CQ via napi_schedule(). This triggers mana_poll_tx_cq() through the normal NAPI path, processing any pending completions without relying on the interrupt and recovering missed-interrupt scenarios without queue reset. If any subsequent TX timeout fires on any queue, within 2 minutes of the previous one, escalate to the existing port-level detach/attach reset, as the CQE poll did not recover the queue. This makes the TX timeout recovery three-tiered: Level 1: CQE poll via napi_schedule() (this patch) Level 2: Port queue reset (detach/attach) Level 3: device reset(FLR) Co-developed-by: Dipayaan Roy Signed-off-by: Dipayaan Roy Signed-off-by: Sahil Chandna --- drivers/net/ethernet/microsoft/mana/mana_en.c | 31 ++++++++++++++++--- .../ethernet/microsoft/mana/mana_ethtool.c | 2 ++ include/net/mana/mana.h | 4 +++ 3 files changed, 33 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c index e6d494df22e4..0d8c8b8fbc83 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_en.c +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c @@ -336,6 +336,9 @@ static void mana_per_port_queue_reset_work_handler(struct work_struct *work) if (err) netdev_err(ndev, "mana_attach failed: %d\n", err); + /* Let the next TX timeout try a CQE poll recovery first */ + WRITE_ONCE(apc->last_tx_timeout, 0); + dealloc_pre_rxbufs: mana_pre_dealloc_rxbufs(apc); clear_flag: @@ -964,6 +967,7 @@ static void mana_tx_timeout(struct net_device *netdev, unsigned int txqueue) struct mana_port_context *apc = netdev_priv(netdev); struct mana_context *ac = apc->ac; struct gdma_context *gc = ac->gdma_dev->gdma_context; + unsigned long last = READ_ONCE(apc->last_tx_timeout); /* Debug knob for bringup/qualification: when set, log the timeout and * skip the reset so the failing state is preserved for telemetry. @@ -980,11 +984,30 @@ static void mana_tx_timeout(struct net_device *netdev, unsigned int txqueue) if (test_bit(GC_IN_SERVICE, &gc->flags)) return; - /* Note: If there are pending queue reset work for this port(apc), - * subsequent request queued up from here are ignored. This is because - * we are using the same work instance per port(apc). + if (!apc->port_is_up) + return; + + /* If the previous timeout fired less than + * MANA_TX_TIMEOUT_RESET_THRESHOLD ago, the earlier CQE poll did not + * help and queue stalled again : escalate to a port reset. + * Note: If there is pending queue reset work for this port (apc), + * subsequent requests queued up from here are ignored, because the + * same work instance is used per port (apc). */ - queue_work(ac->per_port_queue_reset_wq, &apc->queue_reset_work); + if (last && + time_after(last, jiffies - MANA_TX_TIMEOUT_RESET_THRESHOLD)) { + queue_work(ac->per_port_queue_reset_wq, &apc->queue_reset_work); + return; + } + + /* First timeout, or the previous one was long ago: try to recover by + * polling the TX CQ for completions before escalating to a reset. + */ + if (txqueue < apc->num_queues && apc->tx_qp && apc->tx_qp[txqueue]) { + WRITE_ONCE(apc->last_tx_timeout, jiffies); + apc->eth_stats.tx_cqe_poll_recovery++; + napi_schedule(&apc->tx_qp[txqueue]->tx_cq.napi); + } } static int mana_shaper_set(struct net_shaper_binding *binding, diff --git a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c index a91eb12badca..ff4799c61a6c 100644 --- a/drivers/net/ethernet/microsoft/mana/mana_ethtool.c +++ b/drivers/net/ethernet/microsoft/mana/mana_ethtool.c @@ -22,6 +22,8 @@ static const struct mana_stats_desc mana_eth_stats[] = { tx_linear_pkt_cnt)}, {"rx_cqe_unknown_type", offsetof(struct mana_ethtool_stats, rx_cqe_unknown_type)}, + {"tx_cqe_poll_recovery", offsetof(struct mana_ethtool_stats, + tx_cqe_poll_recovery)}, }; static const struct mana_stats_desc mana_hc_stats[] = { diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h index 09725e3256fa..5de6eaa02102 100644 --- a/include/net/mana/mana.h +++ b/include/net/mana/mana.h @@ -94,6 +94,8 @@ enum mana_priv_flag_bits { #define MANA_RX_FRAG_ALIGNMENT 64 +#define MANA_TX_TIMEOUT_RESET_THRESHOLD (2 * 60 * HZ) + struct mana_stats_rx { u64 packets; u64 bytes; @@ -447,6 +449,7 @@ struct mana_tx_qp { struct mana_ethtool_stats { u64 stop_queue; u64 wake_queue; + u64 tx_cqe_poll_recovery; u64 tx_cqe_err; u64 tx_cqe_unknown_type; u64 tx_linear_pkt_cnt; @@ -566,6 +569,7 @@ struct mana_port_context { struct net_device *ndev; struct work_struct queue_reset_work; + unsigned long last_tx_timeout; /* Debug knob to log TX timeout but skip recovery reset */ bool tx_timeout_skip_reset; -- 2.53.0