Commit 178ca308 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

Revert "net/sched: Fix mirred deadlock on device recursion" 



This reverts commits 0f022d32
and 44180fea.

Prior patch in this series implemented loop detection
in act_mirred, we can remove q->owner to save some cycles
in the fast path.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: default avatarVictor Nogueira <victor@mojatatu.com>
Tested-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20251014171907.3554413-5-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fe946a75

include/net/sch_generic.h

+0 −1
Original line number Diff line number Diff line
@@ -117,7 +117,6 @@ struct Qdisc { 
	struct qdisc_skb_head	q;

	struct gnet_stats_basic_sync bstats;

	struct gnet_stats_queue	qstats;

	int                     owner;

	unsigned long		state;

	unsigned long		state2; /* must be written under qdisc spinlock */

	struct Qdisc            *next_sched;

net/core/dev.c

+0 −6
Original line number Diff line number Diff line
@@ -4167,10 +4167,6 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, 
		return rc;

	}



	if (unlikely(READ_ONCE(q->owner) == smp_processor_id())) {

		kfree_skb_reason(skb, SKB_DROP_REASON_TC_RECLASSIFY_LOOP);

		return NET_XMIT_DROP;

	}

	/*

	 * Heuristic to force contended enqueues to serialize on a

	 * separate lock before trying to get qdisc main lock.
@@ -4210,9 +4206,7 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, 
		qdisc_run_end(q);

		rc = NET_XMIT_SUCCESS;

	} else {

		WRITE_ONCE(q->owner, smp_processor_id());

		rc = dev_qdisc_enqueue(skb, q, &to_free, txq);

		WRITE_ONCE(q->owner, -1);

		if (qdisc_run_begin(q)) {

			if (unlikely(contended)) {

				spin_unlock(&q->busylock);

net/sched/sch_generic.c

+0 −2
Original line number Diff line number Diff line
@@ -679,7 +679,6 @@ struct Qdisc noop_qdisc = { 
		.qlen = 0,

		.lock = __SPIN_LOCK_UNLOCKED(noop_qdisc.skb_bad_txq.lock),

	},

	.owner = -1,

};

EXPORT_SYMBOL(noop_qdisc);
@@ -985,7 +984,6 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, 
	sch->enqueue = ops->enqueue;

	sch->dequeue = ops->dequeue;

	sch->dev_queue = dev_queue;

	sch->owner = -1;

	netdev_hold(dev, &sch->dev_tracker, GFP_KERNEL);

	refcount_set(&sch->refcnt, 1);