Merge branch 'net_sched-dump-no-rtnl'

Eric Dumazet says:

====================
net_sched: first series for RTNL-less qdisc dumps

Medium term goal is to implement "tc qdisc show" without needing
to acquire RTNL.

This first series makes the requested changes in 14 qdisc.

Notes :

 - RTNL is still held in "tc qdisc show", more changes are needed.

 - Qdisc returning many attributes might want/need to provide
   a consistent set of attributes. If that is the case, their
   dump() method could acquire the qdisc spinlock, to pair the
   spinlock acquision in their change() method.

V2: Addressed Simon feedback (Thanks a lot Simon)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/red.h

@@ -233,10 +233,10 @@ static inline void red_set_parms(struct red_parms *p,
 	int delta = qth_max - qth_min;
 	u32 max_p_delta;
 
-	p->qth_min	= qth_min << Wlog;
-	p->qth_max	= qth_max << Wlog;
-	p->Wlog		= Wlog;
-	p->Plog		= Plog;
+	WRITE_ONCE(p->qth_min, qth_min << Wlog);
+	WRITE_ONCE(p->qth_max, qth_max << Wlog);
+	WRITE_ONCE(p->Wlog, Wlog);
+	WRITE_ONCE(p->Plog, Plog);
 	if (delta <= 0)
 		delta = 1;
 	p->qth_delta	= delta;
@@ -244,7 +244,7 @@ static inline void red_set_parms(struct red_parms *p,
 		max_P = red_maxp(Plog);
 		max_P *= delta; /* max_P = (qth_max - qth_min)/2^Plog */
 	}
-	p->max_P = max_P;
+	WRITE_ONCE(p->max_P, max_P);
 	max_p_delta = max_P / delta;
 	max_p_delta = max(max_p_delta, 1U);
 	p->max_P_reciprocal  = reciprocal_value(max_p_delta);
@@ -257,7 +257,7 @@ static inline void red_set_parms(struct red_parms *p,
 	p->target_min = qth_min + 2*delta;
 	p->target_max = qth_min + 3*delta;
 
-	p->Scell_log	= Scell_log;
+	WRITE_ONCE(p->Scell_log, Scell_log);
 	p->Scell_max	= (255 << Scell_log);
 
 	if (stab)

net/sched/sch_cake.c

@@ -2572,6 +2572,8 @@ static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 {
 	struct cake_sched_data *q = qdisc_priv(sch);
 	struct nlattr *tb[TCA_CAKE_MAX + 1];
+	u16 rate_flags;
+	u8 flow_mode;
 	int err;
 
 	err = nla_parse_nested_deprecated(tb, TCA_CAKE_MAX, opt, cake_policy,
@@ -2579,10 +2581,11 @@ static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 	if (err < 0)
 		return err;
 
+	flow_mode = q->flow_mode;
 	if (tb[TCA_CAKE_NAT]) {
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
-		q->flow_mode &= ~CAKE_FLOW_NAT_FLAG;
-		q->flow_mode |= CAKE_FLOW_NAT_FLAG *
+		flow_mode &= ~CAKE_FLOW_NAT_FLAG;
+		flow_mode |= CAKE_FLOW_NAT_FLAG *
 			!!nla_get_u32(tb[TCA_CAKE_NAT]);
 #else
 		NL_SET_ERR_MSG_ATTR(extack, tb[TCA_CAKE_NAT],
@@ -2592,29 +2595,34 @@ static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 	}
 
 	if (tb[TCA_CAKE_BASE_RATE64])
-		q->rate_bps = nla_get_u64(tb[TCA_CAKE_BASE_RATE64]);
+		WRITE_ONCE(q->rate_bps,
+			   nla_get_u64(tb[TCA_CAKE_BASE_RATE64]));
 
 	if (tb[TCA_CAKE_DIFFSERV_MODE])
-		q->tin_mode = nla_get_u32(tb[TCA_CAKE_DIFFSERV_MODE]);
+		WRITE_ONCE(q->tin_mode,
+			   nla_get_u32(tb[TCA_CAKE_DIFFSERV_MODE]));
 
+	rate_flags = q->rate_flags;
 	if (tb[TCA_CAKE_WASH]) {
 		if (!!nla_get_u32(tb[TCA_CAKE_WASH]))
-			q->rate_flags |= CAKE_FLAG_WASH;
+			rate_flags |= CAKE_FLAG_WASH;
 		else
-			q->rate_flags &= ~CAKE_FLAG_WASH;
+			rate_flags &= ~CAKE_FLAG_WASH;
 	}
 
 	if (tb[TCA_CAKE_FLOW_MODE])
-		q->flow_mode = ((q->flow_mode & CAKE_FLOW_NAT_FLAG) |
+		flow_mode = ((flow_mode & CAKE_FLOW_NAT_FLAG) |
 				(nla_get_u32(tb[TCA_CAKE_FLOW_MODE]) &
 					CAKE_FLOW_MASK));
 
 	if (tb[TCA_CAKE_ATM])
-		q->atm_mode = nla_get_u32(tb[TCA_CAKE_ATM]);
+		WRITE_ONCE(q->atm_mode,
+			   nla_get_u32(tb[TCA_CAKE_ATM]));
 
 	if (tb[TCA_CAKE_OVERHEAD]) {
-		q->rate_overhead = nla_get_s32(tb[TCA_CAKE_OVERHEAD]);
-		q->rate_flags |= CAKE_FLAG_OVERHEAD;
+		WRITE_ONCE(q->rate_overhead,
+			   nla_get_s32(tb[TCA_CAKE_OVERHEAD]));
+		rate_flags |= CAKE_FLAG_OVERHEAD;
 
 		q->max_netlen = 0;
 		q->max_adjlen = 0;
@@ -2623,7 +2631,7 @@ static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 	}
 
 	if (tb[TCA_CAKE_RAW]) {
-		q->rate_flags &= ~CAKE_FLAG_OVERHEAD;
+		rate_flags &= ~CAKE_FLAG_OVERHEAD;
 
 		q->max_netlen = 0;
 		q->max_adjlen = 0;
@@ -2632,54 +2640,58 @@ static int cake_change(struct Qdisc *sch, struct nlattr *opt,
 	}
 
 	if (tb[TCA_CAKE_MPU])
-		q->rate_mpu = nla_get_u32(tb[TCA_CAKE_MPU]);
+		WRITE_ONCE(q->rate_mpu,
+			   nla_get_u32(tb[TCA_CAKE_MPU]));
 
 	if (tb[TCA_CAKE_RTT]) {
-		q->interval = nla_get_u32(tb[TCA_CAKE_RTT]);
+		u32 interval = nla_get_u32(tb[TCA_CAKE_RTT]);
 
-		if (!q->interval)
-			q->interval = 1;
+		WRITE_ONCE(q->interval, max(interval, 1U));
 	}
 
 	if (tb[TCA_CAKE_TARGET]) {
-		q->target = nla_get_u32(tb[TCA_CAKE_TARGET]);
+		u32 target = nla_get_u32(tb[TCA_CAKE_TARGET]);
 
-		if (!q->target)
-			q->target = 1;
+		WRITE_ONCE(q->target, max(target, 1U));
 	}
 
 	if (tb[TCA_CAKE_AUTORATE]) {
 		if (!!nla_get_u32(tb[TCA_CAKE_AUTORATE]))
-			q->rate_flags |= CAKE_FLAG_AUTORATE_INGRESS;
+			rate_flags |= CAKE_FLAG_AUTORATE_INGRESS;
 		else
-			q->rate_flags &= ~CAKE_FLAG_AUTORATE_INGRESS;
+			rate_flags &= ~CAKE_FLAG_AUTORATE_INGRESS;
 	}
 
 	if (tb[TCA_CAKE_INGRESS]) {
 		if (!!nla_get_u32(tb[TCA_CAKE_INGRESS]))
-			q->rate_flags |= CAKE_FLAG_INGRESS;
+			rate_flags |= CAKE_FLAG_INGRESS;
 		else
-			q->rate_flags &= ~CAKE_FLAG_INGRESS;
+			rate_flags &= ~CAKE_FLAG_INGRESS;
 	}
 
 	if (tb[TCA_CAKE_ACK_FILTER])
-		q->ack_filter = nla_get_u32(tb[TCA_CAKE_ACK_FILTER]);
+		WRITE_ONCE(q->ack_filter,
+			   nla_get_u32(tb[TCA_CAKE_ACK_FILTER]));
 
 	if (tb[TCA_CAKE_MEMORY])
-		q->buffer_config_limit = nla_get_u32(tb[TCA_CAKE_MEMORY]);
+		WRITE_ONCE(q->buffer_config_limit,
+			   nla_get_u32(tb[TCA_CAKE_MEMORY]));
 
 	if (tb[TCA_CAKE_SPLIT_GSO]) {
 		if (!!nla_get_u32(tb[TCA_CAKE_SPLIT_GSO]))
-			q->rate_flags |= CAKE_FLAG_SPLIT_GSO;
+			rate_flags |= CAKE_FLAG_SPLIT_GSO;
 		else
-			q->rate_flags &= ~CAKE_FLAG_SPLIT_GSO;
+			rate_flags &= ~CAKE_FLAG_SPLIT_GSO;
 	}
 
 	if (tb[TCA_CAKE_FWMARK]) {
-		q->fwmark_mask = nla_get_u32(tb[TCA_CAKE_FWMARK]);
-		q->fwmark_shft = q->fwmark_mask ? __ffs(q->fwmark_mask) : 0;
+		WRITE_ONCE(q->fwmark_mask, nla_get_u32(tb[TCA_CAKE_FWMARK]));
+		WRITE_ONCE(q->fwmark_shft,
+			   q->fwmark_mask ? __ffs(q->fwmark_mask) : 0);
 	}
 
+	WRITE_ONCE(q->rate_flags, rate_flags);
+	WRITE_ONCE(q->flow_mode, flow_mode);
 	if (q->tins) {
 		sch_tree_lock(sch);
 		cake_reconfigure(sch);
@@ -2774,68 +2786,72 @@ static int cake_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct cake_sched_data *q = qdisc_priv(sch);
 	struct nlattr *opts;
+	u16 rate_flags;
+	u8 flow_mode;
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
 	if (!opts)
 		goto nla_put_failure;
 
-	if (nla_put_u64_64bit(skb, TCA_CAKE_BASE_RATE64, q->rate_bps,
-			      TCA_CAKE_PAD))
+	if (nla_put_u64_64bit(skb, TCA_CAKE_BASE_RATE64,
+			      READ_ONCE(q->rate_bps), TCA_CAKE_PAD))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_FLOW_MODE,
-			q->flow_mode & CAKE_FLOW_MASK))
+	flow_mode = READ_ONCE(q->flow_mode);
+	if (nla_put_u32(skb, TCA_CAKE_FLOW_MODE, flow_mode & CAKE_FLOW_MASK))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_RTT, q->interval))
+	if (nla_put_u32(skb, TCA_CAKE_RTT, READ_ONCE(q->interval)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_TARGET, q->target))
+	if (nla_put_u32(skb, TCA_CAKE_TARGET, READ_ONCE(q->target)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_MEMORY, q->buffer_config_limit))
+	if (nla_put_u32(skb, TCA_CAKE_MEMORY,
+			READ_ONCE(q->buffer_config_limit)))
 		goto nla_put_failure;
 
+	rate_flags = READ_ONCE(q->rate_flags);
 	if (nla_put_u32(skb, TCA_CAKE_AUTORATE,
-			!!(q->rate_flags & CAKE_FLAG_AUTORATE_INGRESS)))
+			!!(rate_flags & CAKE_FLAG_AUTORATE_INGRESS)))
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CAKE_INGRESS,
-			!!(q->rate_flags & CAKE_FLAG_INGRESS)))
+			!!(rate_flags & CAKE_FLAG_INGRESS)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_ACK_FILTER, q->ack_filter))
+	if (nla_put_u32(skb, TCA_CAKE_ACK_FILTER, READ_ONCE(q->ack_filter)))
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CAKE_NAT,
-			!!(q->flow_mode & CAKE_FLOW_NAT_FLAG)))
+			!!(flow_mode & CAKE_FLOW_NAT_FLAG)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_DIFFSERV_MODE, q->tin_mode))
+	if (nla_put_u32(skb, TCA_CAKE_DIFFSERV_MODE, READ_ONCE(q->tin_mode)))
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CAKE_WASH,
-			!!(q->rate_flags & CAKE_FLAG_WASH)))
+			!!(rate_flags & CAKE_FLAG_WASH)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_OVERHEAD, q->rate_overhead))
+	if (nla_put_u32(skb, TCA_CAKE_OVERHEAD, READ_ONCE(q->rate_overhead)))
 		goto nla_put_failure;
 
-	if (!(q->rate_flags & CAKE_FLAG_OVERHEAD))
+	if (!(rate_flags & CAKE_FLAG_OVERHEAD))
 		if (nla_put_u32(skb, TCA_CAKE_RAW, 0))
 			goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_ATM, q->atm_mode))
+	if (nla_put_u32(skb, TCA_CAKE_ATM, READ_ONCE(q->atm_mode)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_MPU, q->rate_mpu))
+	if (nla_put_u32(skb, TCA_CAKE_MPU, READ_ONCE(q->rate_mpu)))
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CAKE_SPLIT_GSO,
-			!!(q->rate_flags & CAKE_FLAG_SPLIT_GSO)))
+			!!(rate_flags & CAKE_FLAG_SPLIT_GSO)))
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_CAKE_FWMARK, q->fwmark_mask))
+	if (nla_put_u32(skb, TCA_CAKE_FWMARK, READ_ONCE(q->fwmark_mask)))
 		goto nla_put_failure;
 
 	return nla_nest_end(skb, opts);

net/sched/sch_cbs.c

@@ -389,11 +389,11 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
 	}
 
 	/* Everything went OK, save the parameters used. */
-	q->hicredit = qopt->hicredit;
-	q->locredit = qopt->locredit;
-	q->idleslope = qopt->idleslope * BYTES_PER_KBIT;
-	q->sendslope = qopt->sendslope * BYTES_PER_KBIT;
-	q->offload = qopt->offload;
+	WRITE_ONCE(q->hicredit, qopt->hicredit);
+	WRITE_ONCE(q->locredit, qopt->locredit);
+	WRITE_ONCE(q->idleslope, qopt->idleslope * BYTES_PER_KBIT);
+	WRITE_ONCE(q->sendslope, qopt->sendslope * BYTES_PER_KBIT);
+	WRITE_ONCE(q->offload, qopt->offload);
 
 	return 0;
 }
@@ -459,11 +459,11 @@ static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (!nest)
 		goto nla_put_failure;
 
-	opt.hicredit = q->hicredit;
-	opt.locredit = q->locredit;
-	opt.sendslope = div64_s64(q->sendslope, BYTES_PER_KBIT);
-	opt.idleslope = div64_s64(q->idleslope, BYTES_PER_KBIT);
-	opt.offload = q->offload;
+	opt.hicredit = READ_ONCE(q->hicredit);
+	opt.locredit = READ_ONCE(q->locredit);
+	opt.sendslope = div64_s64(READ_ONCE(q->sendslope), BYTES_PER_KBIT);
+	opt.idleslope = div64_s64(READ_ONCE(q->idleslope), BYTES_PER_KBIT);
+	opt.offload = READ_ONCE(q->offload);
 
 	if (nla_put(skb, TCA_CBS_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;

net/sched/sch_choke.c

@@ -405,8 +405,8 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt,
 	} else
 		sch_tree_lock(sch);
 
-	q->flags = ctl->flags;
-	q->limit = ctl->limit;
+	WRITE_ONCE(q->flags, ctl->flags);
+	WRITE_ONCE(q->limit, ctl->limit);
 
 	red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
 		      ctl->Plog, ctl->Scell_log,
@@ -431,15 +431,16 @@ static int choke_init(struct Qdisc *sch, struct nlattr *opt,
 static int choke_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct choke_sched_data *q = qdisc_priv(sch);
+	u8 Wlog = READ_ONCE(q->parms.Wlog);
 	struct nlattr *opts = NULL;
 	struct tc_red_qopt opt = {
-		.limit		= q->limit,
-		.flags		= q->flags,
-		.qth_min	= q->parms.qth_min >> q->parms.Wlog,
-		.qth_max	= q->parms.qth_max >> q->parms.Wlog,
-		.Wlog		= q->parms.Wlog,
-		.Plog		= q->parms.Plog,
-		.Scell_log	= q->parms.Scell_log,
+		.limit		= READ_ONCE(q->limit),
+		.flags		= READ_ONCE(q->flags),
+		.qth_min	= READ_ONCE(q->parms.qth_min) >> Wlog,
+		.qth_max	= READ_ONCE(q->parms.qth_max) >> Wlog,
+		.Wlog		= Wlog,
+		.Plog		= READ_ONCE(q->parms.Plog),
+		.Scell_log	= READ_ONCE(q->parms.Scell_log),
 	};
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
@@ -447,7 +448,7 @@ static int choke_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_put_failure;
 
 	if (nla_put(skb, TCA_CHOKE_PARMS, sizeof(opt), &opt) ||
-	    nla_put_u32(skb, TCA_CHOKE_MAX_P, q->parms.max_P))
+	    nla_put_u32(skb, TCA_CHOKE_MAX_P, READ_ONCE(q->parms.max_P)))
 		goto nla_put_failure;
 	return nla_nest_end(skb, opts);
 

net/sched/sch_codel.c

@@ -118,26 +118,31 @@ static int codel_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_CODEL_TARGET]) {
 		u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]);
 
-		q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.target,
+			   ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_CE_THRESHOLD]) {
 		u64 val = nla_get_u32(tb[TCA_CODEL_CE_THRESHOLD]);
 
-		q->params.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.ce_threshold,
+			   (val * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_INTERVAL]) {
 		u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]);
 
-		q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->params.interval,
+			   ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_CODEL_LIMIT])
-		sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]);
+		WRITE_ONCE(sch->limit,
+			   nla_get_u32(tb[TCA_CODEL_LIMIT]));
 
 	if (tb[TCA_CODEL_ECN])
-		q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]);
+		WRITE_ONCE(q->params.ecn,
+			   !!nla_get_u32(tb[TCA_CODEL_ECN]));
 
 	qlen = sch->q.qlen;
 	while (sch->q.qlen > sch->limit) {
@@ -183,6 +188,7 @@ static int codel_init(struct Qdisc *sch, struct nlattr *opt,
 static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct codel_sched_data *q = qdisc_priv(sch);
+	codel_time_t ce_threshold;
 	struct nlattr *opts;
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
@@ -190,17 +196,18 @@ static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_CODEL_TARGET,
-			codel_time_to_us(q->params.target)) ||
+			codel_time_to_us(READ_ONCE(q->params.target))) ||
 	    nla_put_u32(skb, TCA_CODEL_LIMIT,
-			sch->limit) ||
+			READ_ONCE(sch->limit)) ||
 	    nla_put_u32(skb, TCA_CODEL_INTERVAL,
-			codel_time_to_us(q->params.interval)) ||
+			codel_time_to_us(READ_ONCE(q->params.interval))) ||
 	    nla_put_u32(skb, TCA_CODEL_ECN,
-			q->params.ecn))
+			READ_ONCE(q->params.ecn)))
 		goto nla_put_failure;
-	if (q->params.ce_threshold != CODEL_DISABLED_THRESHOLD &&
+	ce_threshold = READ_ONCE(q->params.ce_threshold);
+	if (ce_threshold != CODEL_DISABLED_THRESHOLD &&
 	    nla_put_u32(skb, TCA_CODEL_CE_THRESHOLD,
-			codel_time_to_us(q->params.ce_threshold)))
+			codel_time_to_us(ce_threshold)))
 		goto nla_put_failure;
 	return nla_nest_end(skb, opts);
 

net/sched/sch_etf.c

@@ -467,15 +467,15 @@ static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (!nest)
 		goto nla_put_failure;
 
-	opt.delta = q->delta;
-	opt.clockid = q->clockid;
-	if (q->offload)
+	opt.delta = READ_ONCE(q->delta);
+	opt.clockid = READ_ONCE(q->clockid);
+	if (READ_ONCE(q->offload))
 		opt.flags |= TC_ETF_OFFLOAD_ON;
 
-	if (q->deadline_mode)
+	if (READ_ONCE(q->deadline_mode))
 		opt.flags |= TC_ETF_DEADLINE_MODE_ON;
 
-	if (q->skip_sock_check)
+	if (READ_ONCE(q->skip_sock_check))
 		opt.flags |= TC_ETF_SKIP_SOCK_CHECK;
 
 	if (nla_put(skb, TCA_ETF_PARMS, sizeof(opt), &opt))

net/sched/sch_ets.c

@@ -646,7 +646,7 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
 
 	sch_tree_lock(sch);
 
-	q->nbands = nbands;
+	WRITE_ONCE(q->nbands, nbands);
 	for (i = nstrict; i < q->nstrict; i++) {
 		if (q->classes[i].qdisc->q.qlen) {
 			list_add_tail(&q->classes[i].alist, &q->active);
@@ -658,11 +658,11 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
 			list_del(&q->classes[i].alist);
 		qdisc_tree_flush_backlog(q->classes[i].qdisc);
 	}
-	q->nstrict = nstrict;
+	WRITE_ONCE(q->nstrict, nstrict);
 	memcpy(q->prio2band, priomap, sizeof(priomap));
 
 	for (i = 0; i < q->nbands; i++)
-		q->classes[i].quantum = quanta[i];
+		WRITE_ONCE(q->classes[i].quantum, quanta[i]);
 
 	for (i = oldbands; i < q->nbands; i++) {
 		q->classes[i].qdisc = queues[i];
@@ -676,7 +676,7 @@ static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
 	for (i = q->nbands; i < oldbands; i++) {
 		qdisc_put(q->classes[i].qdisc);
 		q->classes[i].qdisc = NULL;
-		q->classes[i].quantum = 0;
+		WRITE_ONCE(q->classes[i].quantum, 0);
 		q->classes[i].deficit = 0;
 		gnet_stats_basic_sync_init(&q->classes[i].bstats);
 		memset(&q->classes[i].qstats, 0, sizeof(q->classes[i].qstats));
@@ -733,6 +733,7 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
 	struct ets_sched *q = qdisc_priv(sch);
 	struct nlattr *opts;
 	struct nlattr *nest;
+	u8 nbands, nstrict;
 	int band;
 	int prio;
 	int err;
@@ -745,21 +746,22 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (!opts)
 		goto nla_err;
 
-	if (nla_put_u8(skb, TCA_ETS_NBANDS, q->nbands))
+	nbands = READ_ONCE(q->nbands);
+	if (nla_put_u8(skb, TCA_ETS_NBANDS, nbands))
 		goto nla_err;
 
-	if (q->nstrict &&
-	    nla_put_u8(skb, TCA_ETS_NSTRICT, q->nstrict))
+	nstrict = READ_ONCE(q->nstrict);
+	if (nstrict && nla_put_u8(skb, TCA_ETS_NSTRICT, nstrict))
 		goto nla_err;
 
-	if (q->nbands > q->nstrict) {
+	if (nbands > nstrict) {
 		nest = nla_nest_start(skb, TCA_ETS_QUANTA);
 		if (!nest)
 			goto nla_err;
 
-		for (band = q->nstrict; band < q->nbands; band++) {
+		for (band = nstrict; band < nbands; band++) {
 			if (nla_put_u32(skb, TCA_ETS_QUANTA_BAND,
-					q->classes[band].quantum))
+					READ_ONCE(q->classes[band].quantum)))
 				goto nla_err;
 		}
 
@@ -771,7 +773,8 @@ static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_err;
 
 	for (prio = 0; prio <= TC_PRIO_MAX; prio++) {
-		if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND, q->prio2band[prio]))
+		if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND,
+			       READ_ONCE(q->prio2band[prio])))
 			goto nla_err;
 	}
 

net/sched/sch_fifo.c

@@ -19,7 +19,8 @@
 static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 			 struct sk_buff **to_free)
 {
-	if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit))
+	if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <=
+		   READ_ONCE(sch->limit)))
 		return qdisc_enqueue_tail(skb, sch);
 
 	return qdisc_drop(skb, sch, to_free);
@@ -28,7 +29,7 @@ static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 			 struct sk_buff **to_free)
 {
-	if (likely(sch->q.qlen < sch->limit))
+	if (likely(sch->q.qlen < READ_ONCE(sch->limit)))
 		return qdisc_enqueue_tail(skb, sch);
 
 	return qdisc_drop(skb, sch, to_free);
@@ -39,7 +40,7 @@ static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 {
 	unsigned int prev_backlog;
 
-	if (likely(sch->q.qlen < sch->limit))
+	if (likely(sch->q.qlen < READ_ONCE(sch->limit)))
 		return qdisc_enqueue_tail(skb, sch);
 
 	prev_backlog = sch->qstats.backlog;
@@ -105,14 +106,14 @@ static int __fifo_init(struct Qdisc *sch, struct nlattr *opt,
 		if (is_bfifo)
 			limit *= psched_mtu(qdisc_dev(sch));
 
-		sch->limit = limit;
+		WRITE_ONCE(sch->limit, limit);
 	} else {
 		struct tc_fifo_qopt *ctl = nla_data(opt);
 
 		if (nla_len(opt) < sizeof(*ctl))
 			return -EINVAL;
 
-		sch->limit = ctl->limit;
+		WRITE_ONCE(sch->limit, ctl->limit);
 	}
 
 	if (is_bfifo)
@@ -154,7 +155,7 @@ static void fifo_destroy(struct Qdisc *sch)
 
 static int __fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
-	struct tc_fifo_qopt opt = { .limit = sch->limit };
+	struct tc_fifo_qopt opt = { .limit = READ_ONCE(sch->limit) };
 
 	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 		goto nla_put_failure;

net/sched/sch_fq.c

@@ -106,6 +106,8 @@ struct fq_perband_flows {
 	int		    quantum; /* based on band nr : 576KB, 192KB, 64KB */
 };
 
+#define FQ_PRIO2BAND_CRUMB_SIZE ((TC_PRIO_MAX + 1) >> 2)
+
 struct fq_sched_data {
 /* Read mostly cache line */
 
@@ -122,7 +124,7 @@ struct fq_sched_data {
 	u8		rate_enable;
 	u8		fq_trees_log;
 	u8		horizon_drop;
-	u8		prio2band[(TC_PRIO_MAX + 1) >> 2];
+	u8		prio2band[FQ_PRIO2BAND_CRUMB_SIZE];
 	u32		timer_slack; /* hrtimer slack in ns */
 
 /* Read/Write fields. */
@@ -159,7 +161,7 @@ struct fq_sched_data {
 /* return the i-th 2-bit value ("crumb") */
 static u8 fq_prio2band(const u8 *prio2band, unsigned int prio)
 {
-	return (prio2band[prio / 4] >> (2 * (prio & 0x3))) & 0x3;
+	return (READ_ONCE(prio2band[prio / 4]) >> (2 * (prio & 0x3))) & 0x3;
 }
 
 /*
@@ -888,7 +890,7 @@ static int fq_resize(struct Qdisc *sch, u32 log)
 		fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
 
 	q->fq_root = array;
-	q->fq_trees_log = log;
+	WRITE_ONCE(q->fq_trees_log, log);
 
 	sch_tree_unlock(sch);
 
@@ -927,11 +929,15 @@ static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
 static void fq_prio2band_compress_crumb(const u8 *in, u8 *out)
 {
 	const int num_elems = TC_PRIO_MAX + 1;
+	u8 tmp[FQ_PRIO2BAND_CRUMB_SIZE];
 	int i;
 
-	memset(out, 0, num_elems / 4);
+	memset(tmp, 0, sizeof(tmp));
 	for (i = 0; i < num_elems; i++)
-		out[i / 4] |= in[i] << (2 * (i & 0x3));
+		tmp[i / 4] |= in[i] << (2 * (i & 0x3));
+
+	for (i = 0; i < FQ_PRIO2BAND_CRUMB_SIZE; i++)
+		WRITE_ONCE(out[i], tmp[i]);
 }
 
 static void fq_prio2band_decompress_crumb(const u8 *in, u8 *out)
@@ -958,7 +964,7 @@ static int fq_load_weights(struct fq_sched_data *q,
 		}
 	}
 	for (i = 0; i < FQ_BANDS; i++)
-		q->band_flows[i].quantum = weights[i];
+		WRITE_ONCE(q->band_flows[i].quantum, weights[i]);
 	return 0;
 }
 
@@ -1011,16 +1017,18 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 			err = -EINVAL;
 	}
 	if (tb[TCA_FQ_PLIMIT])
-		sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]);
+		WRITE_ONCE(sch->limit,
+			   nla_get_u32(tb[TCA_FQ_PLIMIT]));
 
 	if (tb[TCA_FQ_FLOW_PLIMIT])
-		q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]);
+		WRITE_ONCE(q->flow_plimit,
+			   nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]));
 
 	if (tb[TCA_FQ_QUANTUM]) {
 		u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
 
 		if (quantum > 0 && quantum <= (1 << 20)) {
-			q->quantum = quantum;
+			WRITE_ONCE(q->quantum, quantum);
 		} else {
 			NL_SET_ERR_MSG_MOD(extack, "invalid quantum");
 			err = -EINVAL;
@@ -1028,7 +1036,8 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 	}
 
 	if (tb[TCA_FQ_INITIAL_QUANTUM])
-		q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
+		WRITE_ONCE(q->initial_quantum,
+			   nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]));
 
 	if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
 		pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
@@ -1037,17 +1046,19 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_FQ_FLOW_MAX_RATE]) {
 		u32 rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
 
-		q->flow_max_rate = (rate == ~0U) ? ~0UL : rate;
+		WRITE_ONCE(q->flow_max_rate,
+			   (rate == ~0U) ? ~0UL : rate);
 	}
 	if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
-		q->low_rate_threshold =
-			nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
+		WRITE_ONCE(q->low_rate_threshold,
+			   nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]));
 
 	if (tb[TCA_FQ_RATE_ENABLE]) {
 		u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
 
 		if (enable <= 1)
-			q->rate_enable = enable;
+			WRITE_ONCE(q->rate_enable,
+				   enable);
 		else
 			err = -EINVAL;
 	}
@@ -1055,7 +1066,8 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
 		u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
 
-		q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
+		WRITE_ONCE(q->flow_refill_delay,
+			   usecs_to_jiffies(usecs_delay));
 	}
 
 	if (!err && tb[TCA_FQ_PRIOMAP])
@@ -1065,21 +1077,26 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt,
 		err = fq_load_weights(q, tb[TCA_FQ_WEIGHTS], extack);
 
 	if (tb[TCA_FQ_ORPHAN_MASK])
-		q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
+		WRITE_ONCE(q->orphan_mask,
+			   nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]));
 
 	if (tb[TCA_FQ_CE_THRESHOLD])
-		q->ce_threshold = (u64)NSEC_PER_USEC *
-				  nla_get_u32(tb[TCA_FQ_CE_THRESHOLD]);
+		WRITE_ONCE(q->ce_threshold,
+			   (u64)NSEC_PER_USEC *
+			   nla_get_u32(tb[TCA_FQ_CE_THRESHOLD]));
 
 	if (tb[TCA_FQ_TIMER_SLACK])
-		q->timer_slack = nla_get_u32(tb[TCA_FQ_TIMER_SLACK]);
+		WRITE_ONCE(q->timer_slack,
+			   nla_get_u32(tb[TCA_FQ_TIMER_SLACK]));
 
 	if (tb[TCA_FQ_HORIZON])
-		q->horizon = (u64)NSEC_PER_USEC *
-				  nla_get_u32(tb[TCA_FQ_HORIZON]);
+		WRITE_ONCE(q->horizon,
+			   (u64)NSEC_PER_USEC *
+			   nla_get_u32(tb[TCA_FQ_HORIZON]));
 
 	if (tb[TCA_FQ_HORIZON_DROP])
-		q->horizon_drop = nla_get_u8(tb[TCA_FQ_HORIZON_DROP]);
+		WRITE_ONCE(q->horizon_drop,
+			   nla_get_u8(tb[TCA_FQ_HORIZON_DROP]));
 
 	if (!err) {
 
@@ -1160,13 +1177,13 @@ static int fq_init(struct Qdisc *sch, struct nlattr *opt,
 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct fq_sched_data *q = qdisc_priv(sch);
-	u64 ce_threshold = q->ce_threshold;
 	struct tc_prio_qopt prio = {
 		.bands = FQ_BANDS,
 	};
-	u64 horizon = q->horizon;
 	struct nlattr *opts;
+	u64 ce_threshold;
 	s32 weights[3];
+	u64 horizon;
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
 	if (opts == NULL)
@@ -1174,35 +1191,48 @@ static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
 
 	/* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
 
+	ce_threshold = READ_ONCE(q->ce_threshold);
 	do_div(ce_threshold, NSEC_PER_USEC);
+
+	horizon = READ_ONCE(q->horizon);
 	do_div(horizon, NSEC_PER_USEC);
 
-	if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) ||
-	    nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) ||
-	    nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) ||
-	    nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) ||
-	    nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) ||
+	if (nla_put_u32(skb, TCA_FQ_PLIMIT,
+			READ_ONCE(sch->limit)) ||
+	    nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT,
+			READ_ONCE(q->flow_plimit)) ||
+	    nla_put_u32(skb, TCA_FQ_QUANTUM,
+			READ_ONCE(q->quantum)) ||
+	    nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM,
+			READ_ONCE(q->initial_quantum)) ||
+	    nla_put_u32(skb, TCA_FQ_RATE_ENABLE,
+			READ_ONCE(q->rate_enable)) ||
 	    nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE,
-			min_t(unsigned long, q->flow_max_rate, ~0U)) ||
+			min_t(unsigned long,
+			      READ_ONCE(q->flow_max_rate), ~0U)) ||
 	    nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
-			jiffies_to_usecs(q->flow_refill_delay)) ||
-	    nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
+			jiffies_to_usecs(READ_ONCE(q->flow_refill_delay))) ||
+	    nla_put_u32(skb, TCA_FQ_ORPHAN_MASK,
+			READ_ONCE(q->orphan_mask)) ||
 	    nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
-			q->low_rate_threshold) ||
+			READ_ONCE(q->low_rate_threshold)) ||
 	    nla_put_u32(skb, TCA_FQ_CE_THRESHOLD, (u32)ce_threshold) ||
-	    nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log) ||
-	    nla_put_u32(skb, TCA_FQ_TIMER_SLACK, q->timer_slack) ||
+	    nla_put_u32(skb, TCA_FQ_BUCKETS_LOG,
+			READ_ONCE(q->fq_trees_log)) ||
+	    nla_put_u32(skb, TCA_FQ_TIMER_SLACK,
+			READ_ONCE(q->timer_slack)) ||
 	    nla_put_u32(skb, TCA_FQ_HORIZON, (u32)horizon) ||
-	    nla_put_u8(skb, TCA_FQ_HORIZON_DROP, q->horizon_drop))
+	    nla_put_u8(skb, TCA_FQ_HORIZON_DROP,
+		       READ_ONCE(q->horizon_drop)))
 		goto nla_put_failure;
 
 	fq_prio2band_decompress_crumb(q->prio2band, prio.priomap);
 	if (nla_put(skb, TCA_FQ_PRIOMAP, sizeof(prio), &prio))
 		goto nla_put_failure;
 
-	weights[0] = q->band_flows[0].quantum;
-	weights[1] = q->band_flows[1].quantum;
-	weights[2] = q->band_flows[2].quantum;
+	weights[0] = READ_ONCE(q->band_flows[0].quantum);
+	weights[1] = READ_ONCE(q->band_flows[1].quantum);
+	weights[2] = READ_ONCE(q->band_flows[2].quantum);
 	if (nla_put(skb, TCA_FQ_WEIGHTS, sizeof(weights), &weights))
 		goto nla_put_failure;
 

net/sched/sch_fq_codel.c

@@ -396,40 +396,49 @@ static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_FQ_CODEL_TARGET]) {
 		u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
 
-		q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->cparams.target,
+			   (target * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_FQ_CODEL_CE_THRESHOLD]) {
 		u64 val = nla_get_u32(tb[TCA_FQ_CODEL_CE_THRESHOLD]);
 
-		q->cparams.ce_threshold = (val * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->cparams.ce_threshold,
+			   (val * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR])
-		q->cparams.ce_threshold_selector = nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR]);
+		WRITE_ONCE(q->cparams.ce_threshold_selector,
+			   nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR]));
 	if (tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK])
-		q->cparams.ce_threshold_mask = nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK]);
+		WRITE_ONCE(q->cparams.ce_threshold_mask,
+			   nla_get_u8(tb[TCA_FQ_CODEL_CE_THRESHOLD_MASK]));
 
 	if (tb[TCA_FQ_CODEL_INTERVAL]) {
 		u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
 
-		q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT;
+		WRITE_ONCE(q->cparams.interval,
+			   (interval * NSEC_PER_USEC) >> CODEL_SHIFT);
 	}
 
 	if (tb[TCA_FQ_CODEL_LIMIT])
-		sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]);
+		WRITE_ONCE(sch->limit,
+			   nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]));
 
 	if (tb[TCA_FQ_CODEL_ECN])
-		q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]);
+		WRITE_ONCE(q->cparams.ecn,
+			   !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]));
 
 	if (quantum)
-		q->quantum = quantum;
+		WRITE_ONCE(q->quantum, quantum);
 
 	if (tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])
-		q->drop_batch_size = max(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE]));
+		WRITE_ONCE(q->drop_batch_size,
+			   max(1U, nla_get_u32(tb[TCA_FQ_CODEL_DROP_BATCH_SIZE])));
 
 	if (tb[TCA_FQ_CODEL_MEMORY_LIMIT])
-		q->memory_limit = min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT]));
+		WRITE_ONCE(q->memory_limit,
+			   min(1U << 31, nla_get_u32(tb[TCA_FQ_CODEL_MEMORY_LIMIT])));
 
 	while (sch->q.qlen > sch->limit ||
 	       q->memory_usage > q->memory_limit) {
@@ -522,6 +531,7 @@ static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt,
 static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct fq_codel_sched_data *q = qdisc_priv(sch);
+	codel_time_t ce_threshold;
 	struct nlattr *opts;
 
 	opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
@@ -529,30 +539,33 @@ static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
 		goto nla_put_failure;
 
 	if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET,
-			codel_time_to_us(q->cparams.target)) ||
+			codel_time_to_us(READ_ONCE(q->cparams.target))) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_LIMIT,
-			sch->limit) ||
+			READ_ONCE(sch->limit)) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL,
-			codel_time_to_us(q->cparams.interval)) ||
+			codel_time_to_us(READ_ONCE(q->cparams.interval))) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_ECN,
-			q->cparams.ecn) ||
+			READ_ONCE(q->cparams.ecn)) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
-			q->quantum) ||
+			READ_ONCE(q->quantum)) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_DROP_BATCH_SIZE,
-			q->drop_batch_size) ||
+			READ_ONCE(q->drop_batch_size)) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_MEMORY_LIMIT,
-			q->memory_limit) ||
+			READ_ONCE(q->memory_limit)) ||
 	    nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
-			q->flows_cnt))
+			READ_ONCE(q->flows_cnt)))
 		goto nla_put_failure;
 
-	if (q->cparams.ce_threshold != CODEL_DISABLED_THRESHOLD) {
+	ce_threshold = READ_ONCE(q->cparams.ce_threshold);
+	if (ce_threshold != CODEL_DISABLED_THRESHOLD) {
 		if (nla_put_u32(skb, TCA_FQ_CODEL_CE_THRESHOLD,
-				codel_time_to_us(q->cparams.ce_threshold)))
+				codel_time_to_us(ce_threshold)))
 			goto nla_put_failure;
-		if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR, q->cparams.ce_threshold_selector))
+		if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_SELECTOR,
+			       READ_ONCE(q->cparams.ce_threshold_selector)))
 			goto nla_put_failure;
-		if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_MASK, q->cparams.ce_threshold_mask))
+		if (nla_put_u8(skb, TCA_FQ_CODEL_CE_THRESHOLD_MASK,
+			       READ_ONCE(q->cparams.ce_threshold_mask)))
 			goto nla_put_failure;
 	}
 

net/sched/sch_fq_pie.c

@@ -299,8 +299,8 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
 	if (tb[TCA_FQ_PIE_LIMIT]) {
 		u32 limit = nla_get_u32(tb[TCA_FQ_PIE_LIMIT]);
 
-		q->p_params.limit = limit;
-		sch->limit = limit;
+		WRITE_ONCE(q->p_params.limit, limit);
+		WRITE_ONCE(sch->limit, limit);
 	}
 	if (tb[TCA_FQ_PIE_FLOWS]) {
 		if (q->flows) {
@@ -322,39 +322,45 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
 		u32 target = nla_get_u32(tb[TCA_FQ_PIE_TARGET]);
 
 		/* convert to pschedtime */
-		q->p_params.target =
-			PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC);
+		WRITE_ONCE(q->p_params.target,
+			   PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC));
 	}
 
 	/* tupdate is in jiffies */
 	if (tb[TCA_FQ_PIE_TUPDATE])
-		q->p_params.tupdate =
-			usecs_to_jiffies(nla_get_u32(tb[TCA_FQ_PIE_TUPDATE]));
+		WRITE_ONCE(q->p_params.tupdate,
+			usecs_to_jiffies(nla_get_u32(tb[TCA_FQ_PIE_TUPDATE])));
 
 	if (tb[TCA_FQ_PIE_ALPHA])
-		q->p_params.alpha = nla_get_u32(tb[TCA_FQ_PIE_ALPHA]);
+		WRITE_ONCE(q->p_params.alpha,
+			   nla_get_u32(tb[TCA_FQ_PIE_ALPHA]));
 
 	if (tb[TCA_FQ_PIE_BETA])
-		q->p_params.beta = nla_get_u32(tb[TCA_FQ_PIE_BETA]);
+		WRITE_ONCE(q->p_params.beta,
+			   nla_get_u32(tb[TCA_FQ_PIE_BETA]));
 
 	if (tb[TCA_FQ_PIE_QUANTUM])
-		q->quantum = nla_get_u32(tb[TCA_FQ_PIE_QUANTUM]);
+		WRITE_ONCE(q->quantum, nla_get_u32(tb[TCA_FQ_PIE_QUANTUM]));
 
 	if (tb[TCA_FQ_PIE_MEMORY_LIMIT])
-		q->memory_limit = nla_get_u32(tb[TCA_FQ_PIE_MEMORY_LIMIT]);
+		WRITE_ONCE(q->memory_limit,
+			   nla_get_u32(tb[TCA_FQ_PIE_MEMORY_LIMIT]));
 
 	if (tb[TCA_FQ_PIE_ECN_PROB])
-		q->ecn_prob = nla_get_u32(tb[TCA_FQ_PIE_ECN_PROB]);
+		WRITE_ONCE(q->ecn_prob,
+			   nla_get_u32(tb[TCA_FQ_PIE_ECN_PROB]));
 
 	if (tb[TCA_FQ_PIE_ECN])
-		q->p_params.ecn = nla_get_u32(tb[TCA_FQ_PIE_ECN]);
+		WRITE_ONCE(q->p_params.ecn,
+			   nla_get_u32(tb[TCA_FQ_PIE_ECN]));
 
 	if (tb[TCA_FQ_PIE_BYTEMODE])
-		q->p_params.bytemode = nla_get_u32(tb[TCA_FQ_PIE_BYTEMODE]);
+		WRITE_ONCE(q->p_params.bytemode,
+			   nla_get_u32(tb[TCA_FQ_PIE_BYTEMODE]));
 
 	if (tb[TCA_FQ_PIE_DQ_RATE_ESTIMATOR])
-		q->p_params.dq_rate_estimator =
-			nla_get_u32(tb[TCA_FQ_PIE_DQ_RATE_ESTIMATOR]);
+		WRITE_ONCE(q->p_params.dq_rate_estimator,
+			   nla_get_u32(tb[TCA_FQ_PIE_DQ_RATE_ESTIMATOR]));
 
 	/* Drop excess packets if new limit is lower */
 	while (sch->q.qlen > sch->limit) {
@@ -471,22 +477,23 @@ static int fq_pie_dump(struct Qdisc *sch, struct sk_buff *skb)
 		return -EMSGSIZE;
 
 	/* convert target from pschedtime to us */
-	if (nla_put_u32(skb, TCA_FQ_PIE_LIMIT, sch->limit) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_FLOWS, q->flows_cnt) ||
+	if (nla_put_u32(skb, TCA_FQ_PIE_LIMIT, READ_ONCE(sch->limit)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_FLOWS, READ_ONCE(q->flows_cnt)) ||
 	    nla_put_u32(skb, TCA_FQ_PIE_TARGET,
-			((u32)PSCHED_TICKS2NS(q->p_params.target)) /
+			((u32)PSCHED_TICKS2NS(READ_ONCE(q->p_params.target))) /
 			NSEC_PER_USEC) ||
 	    nla_put_u32(skb, TCA_FQ_PIE_TUPDATE,
-			jiffies_to_usecs(q->p_params.tupdate)) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_ALPHA, q->p_params.alpha) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_BETA, q->p_params.beta) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_QUANTUM, q->quantum) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_MEMORY_LIMIT, q->memory_limit) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_ECN_PROB, q->ecn_prob) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_ECN, q->p_params.ecn) ||
-	    nla_put_u32(skb, TCA_FQ_PIE_BYTEMODE, q->p_params.bytemode) ||
+			jiffies_to_usecs(READ_ONCE(q->p_params.tupdate))) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_ALPHA, READ_ONCE(q->p_params.alpha)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_BETA, READ_ONCE(q->p_params.beta)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_QUANTUM, READ_ONCE(q->quantum)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_MEMORY_LIMIT,
+			READ_ONCE(q->memory_limit)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_ECN_PROB, READ_ONCE(q->ecn_prob)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_ECN, READ_ONCE(q->p_params.ecn)) ||
+	    nla_put_u32(skb, TCA_FQ_PIE_BYTEMODE, READ_ONCE(q->p_params.bytemode)) ||
 	    nla_put_u32(skb, TCA_FQ_PIE_DQ_RATE_ESTIMATOR,
-			q->p_params.dq_rate_estimator))
+			READ_ONCE(q->p_params.dq_rate_estimator)))
 		goto nla_put_failure;
 
 	return nla_nest_end(skb, opts);

net/sched/sch_hfsc.c

@@ -1174,7 +1174,8 @@ hfsc_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
 	}
 
 	/* classification failed, try default class */
-	cl = hfsc_find_class(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
+	cl = hfsc_find_class(TC_H_MAKE(TC_H_MAJ(sch->handle),
+				       READ_ONCE(q->defcls)), sch);
 	if (cl == NULL || cl->level > 0)
 		return NULL;
 
@@ -1443,9 +1444,7 @@ hfsc_change_qdisc(struct Qdisc *sch, struct nlattr *opt,
 		return -EINVAL;
 	qopt = nla_data(opt);
 
-	sch_tree_lock(sch);
-	q->defcls = qopt->defcls;
-	sch_tree_unlock(sch);
+	WRITE_ONCE(q->defcls, qopt->defcls);
 
 	return 0;
 }
@@ -1525,7 +1524,7 @@ hfsc_dump_qdisc(struct Qdisc *sch, struct sk_buff *skb)
 	unsigned char *b = skb_tail_pointer(skb);
 	struct tc_hfsc_qopt qopt;
 
-	qopt.defcls = q->defcls;
+	qopt.defcls = READ_ONCE(q->defcls);
 	if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt))
 		goto nla_put_failure;
 	return skb->len;

net/sched/sch_hhf.c

@@ -534,27 +534,31 @@ static int hhf_change(struct Qdisc *sch, struct nlattr *opt,
 	sch_tree_lock(sch);
 
 	if (tb[TCA_HHF_BACKLOG_LIMIT])
-		sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);
+		WRITE_ONCE(sch->limit, nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]));
 
-	q->quantum = new_quantum;
-	q->hhf_non_hh_weight = new_hhf_non_hh_weight;
+	WRITE_ONCE(q->quantum, new_quantum);
+	WRITE_ONCE(q->hhf_non_hh_weight, new_hhf_non_hh_weight);
 
 	if (tb[TCA_HHF_HH_FLOWS_LIMIT])
-		q->hh_flows_limit = nla_get_u32(tb[TCA_HHF_HH_FLOWS_LIMIT]);
+		WRITE_ONCE(q->hh_flows_limit,
+			   nla_get_u32(tb[TCA_HHF_HH_FLOWS_LIMIT]));
 
 	if (tb[TCA_HHF_RESET_TIMEOUT]) {
 		u32 us = nla_get_u32(tb[TCA_HHF_RESET_TIMEOUT]);
 
-		q->hhf_reset_timeout = usecs_to_jiffies(us);
+		WRITE_ONCE(q->hhf_reset_timeout,
+			   usecs_to_jiffies(us));
 	}
 
 	if (tb[TCA_HHF_ADMIT_BYTES])
-		q->hhf_admit_bytes = nla_get_u32(tb[TCA_HHF_ADMIT_BYTES]);
+		WRITE_ONCE(q->hhf_admit_bytes,
+			   nla_get_u32(tb[TCA_HHF_ADMIT_BYTES]));
 
 	if (tb[TCA_HHF_EVICT_TIMEOUT]) {
 		u32 us = nla_get_u32(tb[TCA_HHF_EVICT_TIMEOUT]);
 
-		q->hhf_evict_timeout = usecs_to_jiffies(us);
+		WRITE_ONCE(q->hhf_evict_timeout,
+			   usecs_to_jiffies(us));
 	}
 
 	qlen = sch->q.qlen;
@@ -657,15 +661,18 @@ static int hhf_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (opts == NULL)
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, TCA_HHF_BACKLOG_LIMIT, sch->limit) ||
-	    nla_put_u32(skb, TCA_HHF_QUANTUM, q->quantum) ||
-	    nla_put_u32(skb, TCA_HHF_HH_FLOWS_LIMIT, q->hh_flows_limit) ||
+	if (nla_put_u32(skb, TCA_HHF_BACKLOG_LIMIT, READ_ONCE(sch->limit)) ||
+	    nla_put_u32(skb, TCA_HHF_QUANTUM, READ_ONCE(q->quantum)) ||
+	    nla_put_u32(skb, TCA_HHF_HH_FLOWS_LIMIT,
+			READ_ONCE(q->hh_flows_limit)) ||
 	    nla_put_u32(skb, TCA_HHF_RESET_TIMEOUT,
-			jiffies_to_usecs(q->hhf_reset_timeout)) ||
-	    nla_put_u32(skb, TCA_HHF_ADMIT_BYTES, q->hhf_admit_bytes) ||
+			jiffies_to_usecs(READ_ONCE(q->hhf_reset_timeout))) ||
+	    nla_put_u32(skb, TCA_HHF_ADMIT_BYTES,
+			READ_ONCE(q->hhf_admit_bytes)) ||
 	    nla_put_u32(skb, TCA_HHF_EVICT_TIMEOUT,
-			jiffies_to_usecs(q->hhf_evict_timeout)) ||
-	    nla_put_u32(skb, TCA_HHF_NON_HH_WEIGHT, q->hhf_non_hh_weight))
+			jiffies_to_usecs(READ_ONCE(q->hhf_evict_timeout))) ||
+	    nla_put_u32(skb, TCA_HHF_NON_HH_WEIGHT,
+			READ_ONCE(q->hhf_non_hh_weight)))
 		goto nla_put_failure;
 
 	return nla_nest_end(skb, opts);

net/sched/sch_pie.c

@@ -156,36 +156,38 @@ static int pie_change(struct Qdisc *sch, struct nlattr *opt,
 		u32 target = nla_get_u32(tb[TCA_PIE_TARGET]);
 
 		/* convert to pschedtime */
-		q->params.target = PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC);
+		WRITE_ONCE(q->params.target,
+			   PSCHED_NS2TICKS((u64)target * NSEC_PER_USEC));
 	}
 
 	/* tupdate is in jiffies */
 	if (tb[TCA_PIE_TUPDATE])
-		q->params.tupdate =
-			usecs_to_jiffies(nla_get_u32(tb[TCA_PIE_TUPDATE]));
+		WRITE_ONCE(q->params.tupdate,
+			   usecs_to_jiffies(nla_get_u32(tb[TCA_PIE_TUPDATE])));
 
 	if (tb[TCA_PIE_LIMIT]) {
 		u32 limit = nla_get_u32(tb[TCA_PIE_LIMIT]);
 
-		q->params.limit = limit;
-		sch->limit = limit;
+		WRITE_ONCE(q->params.limit, limit);
+		WRITE_ONCE(sch->limit, limit);
 	}
 
 	if (tb[TCA_PIE_ALPHA])
-		q->params.alpha = nla_get_u32(tb[TCA_PIE_ALPHA]);
+		WRITE_ONCE(q->params.alpha, nla_get_u32(tb[TCA_PIE_ALPHA]));
 
 	if (tb[TCA_PIE_BETA])
-		q->params.beta = nla_get_u32(tb[TCA_PIE_BETA]);
+		WRITE_ONCE(q->params.beta, nla_get_u32(tb[TCA_PIE_BETA]));
 
 	if (tb[TCA_PIE_ECN])
-		q->params.ecn = nla_get_u32(tb[TCA_PIE_ECN]);
+		WRITE_ONCE(q->params.ecn, nla_get_u32(tb[TCA_PIE_ECN]));
 
 	if (tb[TCA_PIE_BYTEMODE])
-		q->params.bytemode = nla_get_u32(tb[TCA_PIE_BYTEMODE]);
+		WRITE_ONCE(q->params.bytemode,
+			   nla_get_u32(tb[TCA_PIE_BYTEMODE]));
 
 	if (tb[TCA_PIE_DQ_RATE_ESTIMATOR])
-		q->params.dq_rate_estimator =
-				nla_get_u32(tb[TCA_PIE_DQ_RATE_ESTIMATOR]);
+		WRITE_ONCE(q->params.dq_rate_estimator,
+			   nla_get_u32(tb[TCA_PIE_DQ_RATE_ESTIMATOR]));
 
 	/* Drop excess packets if new limit is lower */
 	qlen = sch->q.qlen;
@@ -469,17 +471,18 @@ static int pie_dump(struct Qdisc *sch, struct sk_buff *skb)
 
 	/* convert target from pschedtime to us */
 	if (nla_put_u32(skb, TCA_PIE_TARGET,
-			((u32)PSCHED_TICKS2NS(q->params.target)) /
+			((u32)PSCHED_TICKS2NS(READ_ONCE(q->params.target))) /
 			NSEC_PER_USEC) ||
-	    nla_put_u32(skb, TCA_PIE_LIMIT, sch->limit) ||
+	    nla_put_u32(skb, TCA_PIE_LIMIT, READ_ONCE(sch->limit)) ||
 	    nla_put_u32(skb, TCA_PIE_TUPDATE,
-			jiffies_to_usecs(q->params.tupdate)) ||
-	    nla_put_u32(skb, TCA_PIE_ALPHA, q->params.alpha) ||
-	    nla_put_u32(skb, TCA_PIE_BETA, q->params.beta) ||
+			jiffies_to_usecs(READ_ONCE(q->params.tupdate))) ||
+	    nla_put_u32(skb, TCA_PIE_ALPHA, READ_ONCE(q->params.alpha)) ||
+	    nla_put_u32(skb, TCA_PIE_BETA, READ_ONCE(q->params.beta)) ||
 	    nla_put_u32(skb, TCA_PIE_ECN, q->params.ecn) ||
-	    nla_put_u32(skb, TCA_PIE_BYTEMODE, q->params.bytemode) ||
+	    nla_put_u32(skb, TCA_PIE_BYTEMODE,
+			READ_ONCE(q->params.bytemode)) ||
 	    nla_put_u32(skb, TCA_PIE_DQ_RATE_ESTIMATOR,
-			q->params.dq_rate_estimator))
+			READ_ONCE(q->params.dq_rate_estimator)))
 		goto nla_put_failure;
 
 	return nla_nest_end(skb, opts);

net/sched/sch_skbprio.c

@@ -79,7 +79,9 @@ static int skbprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	prio = min(skb->priority, max_priority);
 
 	qdisc = &q->qdiscs[prio];
-	if (sch->q.qlen < sch->limit) {
+
+	/* sch->limit can change under us from skbprio_change() */
+	if (sch->q.qlen < READ_ONCE(sch->limit)) {
 		__skb_queue_tail(qdisc, skb);
 		qdisc_qstats_backlog_inc(sch, skb);
 		q->qstats[prio].backlog += qdisc_pkt_len(skb);
@@ -172,7 +174,7 @@ static int skbprio_change(struct Qdisc *sch, struct nlattr *opt,
 	if (opt->nla_len != nla_attr_size(sizeof(*ctl)))
 		return -EINVAL;
 
-	sch->limit = ctl->limit;
+	WRITE_ONCE(sch->limit, ctl->limit);
 	return 0;
 }
 
@@ -200,7 +202,7 @@ static int skbprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
 	struct tc_skbprio_qopt opt;
 
-	opt.limit = sch->limit;
+	opt.limit = READ_ONCE(sch->limit);
 
 	if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 		return -1;