From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH net-next 3/8] net: enqueue_to_backlog() change vs not running device
Date: Thu, 28 Mar 2024 17:03:04 +0000 [thread overview]
Message-ID: <20240328170309.2172584-4-edumazet@google.com> (raw)
In-Reply-To: <20240328170309.2172584-1-edumazet@google.com>
If the device attached to the packet given to enqueue_to_backlog()
is not running, we drop the packet.
But we accidentally increase sd->dropped, giving false signals
to admins: sd->dropped should be reserved to cpu backlog pressure,
not to temporary glitches at device dismantles.
While we are at it, perform the netif_running() test before
we get the rps lock, and use REASON_DEV_READY
drop reason instead of NOT_SPECIFIED.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/core/dev.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 5d36a634f468ffdeaca598c3dd033fe06d240bd0..af7a34b0a7d6683c6ffb21dd3388ed678473d95e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4791,12 +4791,13 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
unsigned long flags;
unsigned int qlen;
- reason = SKB_DROP_REASON_NOT_SPECIFIED;
+ reason = SKB_DROP_REASON_DEV_READY;
+ if (!netif_running(skb->dev))
+ goto bad_dev;
+
sd = &per_cpu(softnet_data, cpu);
backlog_lock_irq_save(sd, &flags);
- if (!netif_running(skb->dev))
- goto drop;
qlen = skb_queue_len(&sd->input_pkt_queue);
if (qlen <= READ_ONCE(net_hotdata.max_backlog) &&
!skb_flow_limit(skb, qlen)) {
@@ -4817,10 +4818,10 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
}
reason = SKB_DROP_REASON_CPU_BACKLOG;
-drop:
sd->dropped++;
backlog_unlock_irq_restore(sd, &flags);
+bad_dev:
dev_core_stats_rx_dropped_inc(skb->dev);
kfree_skb_reason(skb, reason);
return NET_RX_DROP;
--
2.44.0.478.gd926399ef9-goog
next prev parent reply other threads:[~2024-03-28 17:03 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-28 17:03 [PATCH net-next 0/8] net: rps: misc changes Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 1/8] net: move kick_defer_list_purge() to net/core/dev.h Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 2/8] net: move dev_xmit_recursion() helpers " Eric Dumazet
2024-03-28 17:03 ` Eric Dumazet [this message]
2024-03-29 3:21 ` [PATCH net-next 3/8] net: enqueue_to_backlog() change vs not running device Jason Xing
2024-03-29 6:31 ` Eric Dumazet
2024-03-29 8:44 ` Jason Xing
2024-03-28 17:03 ` [PATCH net-next 4/8] net: make softnet_data.dropped an atomic_t Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 5/8] net: enqueue_to_backlog() cleanup Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 6/8] net: rps: change input_queue_tail_incr_save() Eric Dumazet
2024-03-29 12:07 ` kernel test robot
2024-03-29 12:29 ` kernel test robot
2024-03-28 17:03 ` [PATCH net-next 7/8] net: rps: add rps_input_queue_head_add() helper Eric Dumazet
2024-03-28 17:03 ` [PATCH net-next 8/8] net: rps: move received_rps field to a better location Eric Dumazet
2024-03-29 5:45 ` [PATCH net-next 0/8] net: rps: misc changes Jakub Kicinski
2024-03-29 6:44 ` Eric Dumazet
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