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authorJesper Dangaard Brouer <brouer@redhat.com>2020-04-30 13:42:22 +0200
committerDavid S. Miller <davem@davemloft.net>2020-05-04 11:50:51 -0700
commitbf6dba76d278d296b385b436d3ac7de56c190d44 (patch)
tree508bb10d40e0b6ed31a688dca7a96257054fa6ab /net
parent09be4c47abe384fe8bd6a6f25012013acacc7729 (diff)
downloadlwn-bf6dba76d278d296b385b436d3ac7de56c190d44.tar.gz
lwn-bf6dba76d278d296b385b436d3ac7de56c190d44.zip
net: sched: fallback to qdisc noqueue if default qdisc setup fail
Currently if the default qdisc setup/init fails, the device ends up with qdisc "noop", which causes all TX packets to get dropped. With the introduction of sysctl net/core/default_qdisc it is possible to change the default qdisc to be more advanced, which opens for the possibility that Qdisc_ops->init() can fail. This patch detect these kind of failures, and choose to fallback to qdisc "noqueue", which is so simple that its init call will not fail. This allows the interface to continue functioning. V2: As this also captures memory failures, which are transient, the device is not kept in IFF_NO_QUEUE state. This allows the net_device to retry to default qdisc assignment. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/sch_generic.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 2efd5b61acef..ad24fa1a51e6 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -1037,10 +1037,9 @@ static void attach_one_default_qdisc(struct net_device *dev,
ops = &pfifo_fast_ops;
qdisc = qdisc_create_dflt(dev_queue, ops, TC_H_ROOT, NULL);
- if (!qdisc) {
- netdev_info(dev, "activation failed\n");
+ if (!qdisc)
return;
- }
+
if (!netif_is_multiqueue(dev))
qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
dev_queue->qdisc_sleeping = qdisc;
@@ -1065,6 +1064,18 @@ static void attach_default_qdiscs(struct net_device *dev)
qdisc->ops->attach(qdisc);
}
}
+
+ /* Detect default qdisc setup/init failed and fallback to "noqueue" */
+ if (dev->qdisc == &noop_qdisc) {
+ netdev_warn(dev, "default qdisc (%s) fail, fallback to %s\n",
+ default_qdisc_ops->id, noqueue_qdisc_ops.id);
+ dev->priv_flags |= IFF_NO_QUEUE;
+ netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+ dev->qdisc = txq->qdisc_sleeping;
+ qdisc_refcount_inc(dev->qdisc);
+ dev->priv_flags ^= IFF_NO_QUEUE;
+ }
+
#ifdef CONFIG_NET_SCHED
if (dev->qdisc != &noop_qdisc)
qdisc_hash_add(dev->qdisc, false);