Re: [PATCH net-next 3/4] net_sched: sch_fq: add fast path for mostly idle qdisc

[kernel test robot <lkp@intel.com>]

:::::: 
:::::: Manual check reason: "low confidence static check warning: net/sched/sch_fq.c:550:1: sparse: sparse: unused label 'queue'"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20230920125418.3675569-4-edumazet@google.com>
References: <20230920125418.3675569-4-edumazet@google.com>
TO: Eric Dumazet <edumazet@google.com>
TO: "David S . Miller" <davem@davemloft.net>
TO: Jakub Kicinski <kuba@kernel.org>
TO: Paolo Abeni <pabeni@redhat.com>
CC: Willem de Bruijn <willemb@google.com>
CC: Jamal Hadi Salim <jhs@mojatatu.com>
CC: Cong Wang <xiyou.wangcong@gmail.com>
CC: Jiri Pirko <jiri@resnulli.us>
CC: netdev@vger.kernel.org
CC: eric.dumazet@gmail.com
CC: Eric Dumazet <edumazet@google.com>

Hi Eric,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/net_sched-sch_fq-struct-sched_data-reorg/20230920-205744
base:   net-next/main
patch link:    https://lore.kernel.org/r/20230920125418.3675569-4-edumazet%40google.com
patch subject: [PATCH net-next 3/4] net_sched: sch_fq: add fast path for mostly idle qdisc
:::::: branch date: 5 days ago
:::::: commit date: 5 days ago
config: x86_64-randconfig-123-20230925 (https://download.01.org/0day-ci/archive/20230925/202309252000.LAvn3XwF-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230925/202309252000.LAvn3XwF-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202309252000.LAvn3XwF-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> net/sched/sch_fq.c:550:1: sparse: sparse: unused label 'queue'

vim +/queue +550 net/sched/sch_fq.c

39d010504e6b44 Eric Dumazet 2020-05-01  505  
b2377bef637585 Eric Dumazet 2023-09-20  506  
520ac30f45519b Eric Dumazet 2016-06-21  507  static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
520ac30f45519b Eric Dumazet 2016-06-21  508  		      struct sk_buff **to_free)
afe4fd062416b1 Eric Dumazet 2013-08-29  509  {
afe4fd062416b1 Eric Dumazet 2013-08-29  510  	struct fq_sched_data *q = qdisc_priv(sch);
afe4fd062416b1 Eric Dumazet 2013-08-29  511  	struct fq_flow *f;
afe4fd062416b1 Eric Dumazet 2013-08-29  512  
afe4fd062416b1 Eric Dumazet 2013-08-29  513  	if (unlikely(sch->q.qlen >= sch->limit))
520ac30f45519b Eric Dumazet 2016-06-21  514  		return qdisc_drop(skb, sch, to_free);
afe4fd062416b1 Eric Dumazet 2013-08-29  515  
b2377bef637585 Eric Dumazet 2023-09-20  516  	q->ktime_cache = ktime_get_ns();
39d010504e6b44 Eric Dumazet 2020-05-01  517  	if (!skb->tstamp) {
b2377bef637585 Eric Dumazet 2023-09-20  518  		fq_skb_cb(skb)->time_to_send = q->ktime_cache;
39d010504e6b44 Eric Dumazet 2020-05-01  519  	} else {
b2377bef637585 Eric Dumazet 2023-09-20  520  		/* Check if packet timestamp is too far in the future. */
39d010504e6b44 Eric Dumazet 2020-05-01  521  		if (fq_packet_beyond_horizon(skb, q)) {
39d010504e6b44 Eric Dumazet 2020-05-01  522  			if (q->horizon_drop) {
39d010504e6b44 Eric Dumazet 2020-05-01  523  					q->stat_horizon_drops++;
39d010504e6b44 Eric Dumazet 2020-05-01  524  					return qdisc_drop(skb, sch, to_free);
39d010504e6b44 Eric Dumazet 2020-05-01  525  			}
39d010504e6b44 Eric Dumazet 2020-05-01  526  			q->stat_horizon_caps++;
39d010504e6b44 Eric Dumazet 2020-05-01  527  			skb->tstamp = q->ktime_cache + q->horizon;
39d010504e6b44 Eric Dumazet 2020-05-01  528  		}
39d010504e6b44 Eric Dumazet 2020-05-01  529  		fq_skb_cb(skb)->time_to_send = skb->tstamp;
39d010504e6b44 Eric Dumazet 2020-05-01  530  	}
39d010504e6b44 Eric Dumazet 2020-05-01  531  
b2377bef637585 Eric Dumazet 2023-09-20  532  	f = fq_classify(sch, skb);
afe4fd062416b1 Eric Dumazet 2013-08-29  533  	if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
afe4fd062416b1 Eric Dumazet 2013-08-29  534  		q->stat_flows_plimit++;
520ac30f45519b Eric Dumazet 2016-06-21  535  		return qdisc_drop(skb, sch, to_free);
afe4fd062416b1 Eric Dumazet 2013-08-29  536  	}
afe4fd062416b1 Eric Dumazet 2013-08-29  537  
afe4fd062416b1 Eric Dumazet 2013-08-29  538  	if (fq_flow_is_detached(f)) {
afe4fd062416b1 Eric Dumazet 2013-08-29  539  		fq_flow_add_tail(&q->new_flows, f);
f52ed89971adbe Eric Dumazet 2013-11-15  540  		if (time_after(jiffies, f->age + q->flow_refill_delay))
f52ed89971adbe Eric Dumazet 2013-11-15  541  			f->credit = max_t(u32, f->credit, q->quantum);
afe4fd062416b1 Eric Dumazet 2013-08-29  542  	}
f52ed89971adbe Eric Dumazet 2013-11-15  543  
afe4fd062416b1 Eric Dumazet 2013-08-29  544  	if (unlikely(f == &q->internal)) {
afe4fd062416b1 Eric Dumazet 2013-08-29  545  		q->stat_internal_packets++;
b2377bef637585 Eric Dumazet 2023-09-20  546  	} else {
b2377bef637585 Eric Dumazet 2023-09-20  547  		if (f->qlen == 0)
b2377bef637585 Eric Dumazet 2023-09-20  548  			q->inactive_flows--;
afe4fd062416b1 Eric Dumazet 2013-08-29  549  	}
b2377bef637585 Eric Dumazet 2023-09-20 @550  queue:
b2377bef637585 Eric Dumazet 2023-09-20  551  	f->qlen++;
b2377bef637585 Eric Dumazet 2023-09-20  552  	/* Note: this overwrites f->age */
b2377bef637585 Eric Dumazet 2023-09-20  553  	flow_queue_add(f, skb);
b2377bef637585 Eric Dumazet 2023-09-20  554  
b2377bef637585 Eric Dumazet 2023-09-20  555  	qdisc_qstats_backlog_inc(sch, skb);
afe4fd062416b1 Eric Dumazet 2013-08-29  556  	sch->q.qlen++;
afe4fd062416b1 Eric Dumazet 2013-08-29  557  
afe4fd062416b1 Eric Dumazet 2013-08-29  558  	return NET_XMIT_SUCCESS;
afe4fd062416b1 Eric Dumazet 2013-08-29  559  }
afe4fd062416b1 Eric Dumazet 2013-08-29  560  

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