From 579e5f8c5ce28ec0b997008b72c1ca9626306ad5 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 16 Nov 2021 19:29:22 -0800 Subject: [PATCH] net: annotate accesses to queue->trans_start In following patches, dev_watchdog() will no longer stop all queues. It will read queue->trans_start locklessly. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- drivers/net/ethernet/apm/xgene/xgene_enet_main.c | 2 +- drivers/net/ethernet/atheros/ag71xx.c | 2 +- drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 4 ++-- drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 2 +- drivers/net/ethernet/ibm/ibmvnic.c | 2 +- drivers/net/ethernet/intel/igb/igb_main.c | 4 ++-- .../ethernet/mellanox/mlx5/core/en/reporter_tx.c | 2 +- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++--- drivers/net/ethernet/ti/am65-cpsw-nuss.c | 2 +- drivers/net/virtio_net.c | 2 +- drivers/net/wireless/marvell/mwifiex/init.c | 2 +- drivers/staging/rtl8192e/rtllib_softmac.c | 2 +- include/linux/netdevice.h | 16 +++++++++++++--- net/sched/sch_generic.c | 8 ++++---- 14 files changed, 33 insertions(+), 23 deletions(-) diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c index 220dc42af31ae..ff2d099aab218 100644 --- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c @@ -869,7 +869,7 @@ static void xgene_enet_timeout(struct net_device *ndev, unsigned int txqueue) for (i = 0; i < pdata->txq_cnt; i++) { txq = netdev_get_tx_queue(ndev, i); - txq->trans_start = jiffies; + txq_trans_cond_update(txq); netif_tx_start_queue(txq); } } diff --git a/drivers/net/ethernet/atheros/ag71xx.c b/drivers/net/ethernet/atheros/ag71xx.c index 88d2ab7483994..e4f30bb7498fe 100644 --- a/drivers/net/ethernet/atheros/ag71xx.c +++ b/drivers/net/ethernet/atheros/ag71xx.c @@ -766,7 +766,7 @@ static bool ag71xx_check_dma_stuck(struct ag71xx *ag) unsigned long timestamp; u32 rx_sm, tx_sm, rx_fd; - timestamp = netdev_get_tx_queue(ag->ndev, 0)->trans_start; + timestamp = READ_ONCE(netdev_get_tx_queue(ag->ndev, 0)->trans_start); if (likely(time_before(jiffies, timestamp + HZ / 10))) return false; diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c index 6b2927d863e2c..d6871437d9515 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c @@ -2325,7 +2325,7 @@ dpaa_start_xmit(struct sk_buff *skb, struct net_device *net_dev) txq = netdev_get_tx_queue(net_dev, queue_mapping); /* LLTX requires to do our own update of trans_start */ - txq->trans_start = jiffies; + txq_trans_cond_update(txq); if (priv->tx_tstamp && skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) { fd.cmd |= cpu_to_be32(FM_FD_CMD_UPD); @@ -2531,7 +2531,7 @@ static int dpaa_xdp_xmit_frame(struct net_device *net_dev, /* Bump the trans_start */ txq = netdev_get_tx_queue(net_dev, smp_processor_id()); - txq->trans_start = jiffies; + txq_trans_cond_update(txq); err = dpaa_xmit(priv, percpu_stats, smp_processor_id(), &fd); if (err) { diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index 13835a37b3a2f..d5100179f8d58 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -2679,7 +2679,7 @@ static bool hns3_get_tx_timeo_queue_info(struct net_device *ndev) unsigned long trans_start; q = netdev_get_tx_queue(ndev, i); - trans_start = q->trans_start; + trans_start = READ_ONCE(q->trans_start); if (netif_xmit_stopped(q) && time_after(jiffies, (trans_start + ndev->watchdog_timeo))) { diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 3cca51735421a..c327fc8860da2 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -2058,7 +2058,7 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) tx_packets++; tx_bytes += skb->len; - txq->trans_start = jiffies; + txq_trans_cond_update(txq); ret = NETDEV_TX_OK; goto out; diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 836be0d3b2910..18a019a471822 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -2927,7 +2927,7 @@ static int igb_xdp_xmit_back(struct igb_adapter *adapter, struct xdp_buff *xdp) nq = txring_txq(tx_ring); __netif_tx_lock(nq, cpu); /* Avoid transmit queue timeout since we share it with the slow path */ - nq->trans_start = jiffies; + txq_trans_cond_update(nq); ret = igb_xmit_xdp_ring(adapter, tx_ring, xdpf); __netif_tx_unlock(nq); @@ -2961,7 +2961,7 @@ static int igb_xdp_xmit(struct net_device *dev, int n, __netif_tx_lock(nq, cpu); /* Avoid transmit queue timeout since we share it with the slow path */ - nq->trans_start = jiffies; + txq_trans_cond_update(nq); for (i = 0; i < n; i++) { struct xdp_frame *xdpf = frames[i]; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c index 4f4bc8726ec4f..8606051332873 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c @@ -565,7 +565,7 @@ int mlx5e_reporter_tx_timeout(struct mlx5e_txqsq *sq) snprintf(err_str, sizeof(err_str), "TX timeout on queue: %d, SQ: 0x%x, CQ: 0x%x, SQ Cons: 0x%x SQ Prod: 0x%x, usecs since last trans: %u", sq->ch_ix, sq->sqn, sq->cq.mcq.cqn, sq->cc, sq->pc, - jiffies_to_usecs(jiffies - sq->txq->trans_start)); + jiffies_to_usecs(jiffies - READ_ONCE(sq->txq->trans_start))); mlx5e_health_report(priv, priv->tx_reporter, err_str, &err_ctx); return to_ctx.status; diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 033c35c09a548..389d125310c15 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2356,7 +2356,7 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget) bool work_done = true; /* Avoids TX time-out as we are sharing with slow path */ - nq->trans_start = jiffies; + txq_trans_cond_update(nq->trans_start); budget = min(budget, stmmac_tx_avail(priv, queue)); @@ -4657,7 +4657,7 @@ static int stmmac_xdp_xmit_back(struct stmmac_priv *priv, __netif_tx_lock(nq, cpu); /* Avoids TX time-out as we are sharing with slow path */ - nq->trans_start = jiffies; + txq_trans_cond_update(nq->trans_start); res = stmmac_xdp_xmit_xdpf(priv, queue, xdpf, false); if (res == STMMAC_XDP_TX) @@ -6293,7 +6293,7 @@ static int stmmac_xdp_xmit(struct net_device *dev, int num_frames, __netif_tx_lock(nq, cpu); /* Avoids TX time-out as we are sharing with slow path */ - nq->trans_start = jiffies; + txq_trans_cond_update(nq); for (i = 0; i < num_frames; i++) { int res; diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c index c092cb61416a1..750cea23e9cd0 100644 --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c @@ -345,7 +345,7 @@ static void am65_cpsw_nuss_ndo_host_tx_timeout(struct net_device *ndev, netif_txq = netdev_get_tx_queue(ndev, txqueue); tx_chn = &common->tx_chns[txqueue]; - trans_start = netif_txq->trans_start; + trans_start = READ_ONCE(netif_txq->trans_start); netdev_err(ndev, "txq:%d DRV_XOFF:%d tmo:%u dql_avail:%d free_desc:%zu\n", txqueue, diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1771d6e5224fd..03e38e38ee4b5 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2694,7 +2694,7 @@ static void virtnet_tx_timeout(struct net_device *dev, unsigned int txqueue) netdev_err(dev, "TX timeout on queue: %u, sq: %s, vq: 0x%x, name: %s, %u usecs ago\n", txqueue, sq->name, sq->vq->index, sq->vq->name, - jiffies_to_usecs(jiffies - txq->trans_start)); + jiffies_to_usecs(jiffies - READ_ONCE(txq->trans_start))); } static const struct net_device_ops virtnet_netdev = { diff --git a/drivers/net/wireless/marvell/mwifiex/init.c b/drivers/net/wireless/marvell/mwifiex/init.c index f006a3d72b404..88c72d1827a00 100644 --- a/drivers/net/wireless/marvell/mwifiex/init.c +++ b/drivers/net/wireless/marvell/mwifiex/init.c @@ -332,7 +332,7 @@ void mwifiex_set_trans_start(struct net_device *dev) int i; for (i = 0; i < dev->num_tx_queues; i++) - netdev_get_tx_queue(dev, i)->trans_start = jiffies; + txq_trans_cond_update(netdev_get_tx_queue(dev, i)); netif_trans_update(dev); } diff --git a/drivers/staging/rtl8192e/rtllib_softmac.c b/drivers/staging/rtl8192e/rtllib_softmac.c index d2726d01c7573..aabbea48223d2 100644 --- a/drivers/staging/rtl8192e/rtllib_softmac.c +++ b/drivers/staging/rtl8192e/rtllib_softmac.c @@ -2515,7 +2515,7 @@ void rtllib_stop_all_queues(struct rtllib_device *ieee) unsigned int i; for (i = 0; i < ieee->dev->num_tx_queues; i++) - netdev_get_tx_queue(ieee->dev, i)->trans_start = jiffies; + txq_trans_cond_update(netdev_get_tx_queue(ieee->dev, i)); netif_tx_stop_all_queues(ieee->dev); } diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 1d22483cf78cc..279409ef2b18c 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4095,10 +4095,21 @@ static inline void __netif_tx_unlock_bh(struct netdev_queue *txq) spin_unlock_bh(&txq->_xmit_lock); } +/* + * txq->trans_start can be read locklessly from dev_watchdog() + */ static inline void txq_trans_update(struct netdev_queue *txq) { if (txq->xmit_lock_owner != -1) - txq->trans_start = jiffies; + WRITE_ONCE(txq->trans_start, jiffies); +} + +static inline void txq_trans_cond_update(struct netdev_queue *txq) +{ + unsigned long now = jiffies; + + if (READ_ONCE(txq->trans_start) != now) + WRITE_ONCE(txq->trans_start, now); } /* legacy drivers only, netdev_start_xmit() sets txq->trans_start */ @@ -4106,8 +4117,7 @@ static inline void netif_trans_update(struct net_device *dev) { struct netdev_queue *txq = netdev_get_tx_queue(dev, 0); - if (txq->trans_start != jiffies) - txq->trans_start = jiffies; + txq_trans_cond_update(txq); } /** diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 1b4328bd495d5..02c46041f76e8 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -434,9 +434,9 @@ unsigned long dev_trans_start(struct net_device *dev) dev = vlan_dev_real_dev(dev); else if (netif_is_macvlan(dev)) dev = macvlan_dev_real_dev(dev); - res = netdev_get_tx_queue(dev, 0)->trans_start; + res = READ_ONCE(netdev_get_tx_queue(dev, 0)->trans_start); for (i = 1; i < dev->num_tx_queues; i++) { - val = netdev_get_tx_queue(dev, i)->trans_start; + val = READ_ONCE(netdev_get_tx_queue(dev, i)->trans_start); if (val && time_after(val, res)) res = val; } @@ -462,7 +462,7 @@ static void dev_watchdog(struct timer_list *t) struct netdev_queue *txq; txq = netdev_get_tx_queue(dev, i); - trans_start = txq->trans_start; + trans_start = READ_ONCE(txq->trans_start); if (netif_xmit_stopped(txq) && time_after(jiffies, (trans_start + dev->watchdog_timeo))) { @@ -1148,7 +1148,7 @@ static void transition_one_qdisc(struct net_device *dev, rcu_assign_pointer(dev_queue->qdisc, new_qdisc); if (need_watchdog_p) { - dev_queue->trans_start = 0; + WRITE_ONCE(dev_queue->trans_start, 0); *need_watchdog_p = 1; } } -- 2.39.5