github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-11 20:13:02 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

net: ntb_netdev: Fix statistics races

Browse Source 
ntb_netdev updates shared net_device stats from per-QP RX and TX
callbacks. Once multiple queues are enabled, concurrent updates can be
lost.

Use per-CPU tstats for packet and byte counters and DEV_STATS_INC() for
less frequent drop and error counters. Callbacks can run synchronously
in the xmit path or asynchronously from a tasklet or the memcpy kthread.
Pin TX updates against migration in the kthread path. Use the IRQ-safe
u64_stats helpers because netpoll can invoke the synchronous path with
IRQs disabled.

Let the core manage tstats while keeping transport teardown after
unregister_netdev(), outside RTNL. RCU lets unregister wait for TX
completions already updating stats, while later completions only consume
the skb and skip accounting and queue wake.

Fixes: 24d9e73c7e ("net: ntb_netdev: Support ethtool channels for multi-queue")
Cc: stable@vger.kernel.org
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260830151617.3546585-1-den@valinux.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Koichiro Den 2026-08-31 00:16:17 +09:00 committed by Jakub Kicinski
parent 975b5b067f
commit 545b63503c
1 changed files with 34 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/net/ntb_netdev.c
View File

@ -127,8 +127,10 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
{
struct ntb_netdev_queue *q = qp_data;
struct ntb_netdev *dev = q->ntdev;
struct pcpu_sw_netstats *tstats;
struct sk_buff *skb, *new_skb;
struct net_device *ndev;
unsigned long flags;
int rc;
ndev = dev->ndev;
@ -139,17 +141,20 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
netdev_dbg(ndev, "%s: %d byte payload received\n", __func__, len);
if (len < 0) {
ndev->stats.rx_errors++;
ndev->stats.rx_length_errors++;
DEV_STATS_INC(ndev, rx_errors);
DEV_STATS_INC(ndev, rx_length_errors);
goto enqueue_again;
}
ndev->stats.rx_packets++;
ndev->stats.rx_bytes += len;
tstats = this_cpu_ptr(ndev->tstats);
flags = u64_stats_update_begin_irqsave(&tstats->syncp);
u64_stats_inc(&tstats->rx_packets);
u64_stats_add(&tstats->rx_bytes, len);
u64_stats_update_end_irqrestore(&tstats->syncp, flags);
new_skb = netdev_alloc_skb(ndev, ndev->mtu + ETH_HLEN);
if (!new_skb) {
ndev->stats.rx_dropped++;
DEV_STATS_INC(ndev, rx_dropped);
goto enqueue_again;
}
@ -166,8 +171,8 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data,
rc = ntb_transport_rx_enqueue(qp, skb, skb->data, ndev->mtu + ETH_HLEN);
if (rc) {
dev_kfree_skb_any(skb);
ndev->stats.rx_errors++;
ndev->stats.rx_fifo_errors++;
DEV_STATS_INC(ndev, rx_errors);
DEV_STATS_INC(ndev, rx_fifo_errors);
}
}
@ -210,25 +215,39 @@ static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
{
struct ntb_netdev_queue *q = qp_data;
struct ntb_netdev *dev = q->ntdev;
struct pcpu_sw_netstats *tstats;
struct net_device *ndev;
struct sk_buff *skb;
unsigned long flags;
bool registered;
ndev = dev->ndev;
skb = data;
if (!skb || !ndev)
return;
rcu_read_lock();
registered = READ_ONCE(ndev->reg_state) == NETREG_REGISTERED;
if (!registered)
goto free_skb;
if (len > 0) {
ndev->stats.tx_packets++;
ndev->stats.tx_bytes += skb->len;
/* The memcpy kthread can migrate, so pin the per-CPU update. */
tstats = get_cpu_ptr(ndev->tstats);
flags = u64_stats_update_begin_irqsave(&tstats->syncp);
u64_stats_inc(&tstats->tx_packets);
u64_stats_add(&tstats->tx_bytes, skb->len);
u64_stats_update_end_irqrestore(&tstats->syncp, flags);
put_cpu_ptr(ndev->tstats);
} else {
ndev->stats.tx_errors++;
ndev->stats.tx_aborted_errors++;
DEV_STATS_INC(ndev, tx_errors);
DEV_STATS_INC(ndev, tx_aborted_errors);
}
free_skb:
dev_kfree_skb_any(skb);
if (ntb_transport_tx_free_entry(qp) >= tx_start) {
if (registered && ntb_transport_tx_free_entry(qp) >= tx_start) {
/* Make sure anybody stopping the queue after this sees the new
* value of ntb_transport_tx_free_entry()
*/
@ -237,6 +256,7 @@ static void ntb_netdev_tx_handler(struct ntb_transport_qp *qp, void *qp_data,
ntb_transport_link_query(q->qp))
netif_wake_subqueue(ndev, q->qid);
}
rcu_read_unlock();
}
static const struct ntb_queue_handlers ntb_netdev_handlers = {
@ -277,7 +297,7 @@ static netdev_tx_t ntb_netdev_start_xmit(struct sk_buff *skb,
drop:
dev_kfree_skb_any(skb);
ndev->stats.tx_dropped++;
DEV_STATS_INC(ndev, tx_dropped);
return NETDEV_TX_OK;
}
@ -647,6 +667,7 @@ static int ntb_netdev_probe(struct device *client_dev)
}
ndev->features = NETIF_F_HIGHDMA;
ndev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE;