This is a note to let you know that I've just added the patch titled
net: annotate accesses to queue->trans_start
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-annotate-accesses-to-queue-trans_start.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f24b5ff2bb0ef5ddbf058c64ef96bf2739be7a1a
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Tue Nov 16 19:29:22 2021 -0800
net: annotate accesses to queue->trans_start
[ Upstream commit 5337824f4dc4bb26f38fbbba4ffb425a92803f15 ]
In following patches, dev_watchdog() will no longer stop all queues.
It will read queue->trans_start locklessly.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 78adb4bcf99e ("igc: Prevent garbled TX queue with XDP ZEROCOPY")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
index 71151f675a498..292c2ce16672f 100644
--- a/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
+++ b/drivers/net/ethernet/apm/xgene/xgene_enet_main.c
@@ -871,7 +871,7 @@ 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 9d8b214c129d2..7e83319b26c14 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 fe5fc2b3406f9..5f5392e6d096a 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 2acf50ed6025a..90314a4adcfd9 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -2645,7 +2645,7 @@ 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 450b4fd9aa7f7..ad45158651ddf 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1910,7 +1910,7 @@ 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 3d380dfff7783..606ac667b8ec6 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -2933,7 +2933,7 @@ 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);
@@ -2967,7 +2967,7 @@ 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 8024599994642..f7fc3c2fa100e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/reporter_tx.c
@@ -570,7 +570,7 @@ 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 a43628dd1f4c2..f2dd8c4deb44d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2416,7 +2416,7 @@ 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));
@@ -4731,7 +4731,7 @@ 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)
@@ -6374,7 +6374,7 @@ 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 daf0779261f3e..934d110ea351d 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/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 ea8bc27fce494..b5a38f0a8d79b 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 b5df2e59a51d3..f1dd4c102e9af 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4473,10 +4473,21 @@ 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 */
@@ -4484,8 +4495,7 @@ 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 02299785209c1..76ed401af066b 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))) {
@@ -1172,7 +1172,7 @@ 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;
}
}
