From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
Victor Nogueira <victor@mojatatu.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH v2 net-next 2/8] net/sched: add qdisc_qlen_inc() and qdisc_qlen_dec()
Date: Sun, 10 May 2026 09:14:49 +0000 [thread overview]
Message-ID: <20260510091455.4039245-3-edumazet@google.com> (raw)
In-Reply-To: <20260510091455.4039245-1-edumazet@google.com>
Helpers to increment or decrement sch->q.qlen, with appropriate
WRITE_ONCE() to prevent store tearing.
Add other WRITE_ONCE() when sch->q.qlen is changed.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
include/net/sch_generic.h | 32 +++++++++++++++++++++-----------
net/sched/sch_api.c | 2 +-
net/sched/sch_cake.c | 8 ++++----
net/sched/sch_cbs.c | 4 ++--
net/sched/sch_choke.c | 8 ++++----
net/sched/sch_drr.c | 4 ++--
net/sched/sch_dualpi2.c | 6 +++---
net/sched/sch_etf.c | 8 ++++----
net/sched/sch_ets.c | 4 ++--
net/sched/sch_fq.c | 6 +++---
net/sched/sch_fq_codel.c | 7 ++++---
net/sched/sch_fq_pie.c | 4 ++--
net/sched/sch_generic.c | 10 +++++-----
net/sched/sch_hfsc.c | 4 ++--
net/sched/sch_hhf.c | 7 ++++---
net/sched/sch_htb.c | 4 ++--
net/sched/sch_mq.c | 5 +++--
net/sched/sch_mqprio.c | 18 ++++++++++--------
net/sched/sch_multiq.c | 4 ++--
net/sched/sch_netem.c | 10 +++++-----
net/sched/sch_prio.c | 4 ++--
net/sched/sch_qfq.c | 6 +++---
net/sched/sch_red.c | 4 ++--
net/sched/sch_sfb.c | 4 ++--
net/sched/sch_sfq.c | 9 +++++----
net/sched/sch_skbprio.c | 4 ++--
net/sched/sch_taprio.c | 4 ++--
net/sched/sch_tbf.c | 6 +++---
net/sched/sch_teql.c | 2 +-
29 files changed, 107 insertions(+), 91 deletions(-)
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index ccfabfac674ef8617faeabd2fcb15daf8a1ea17f..dbb3ba6416e485128c120eb3dacb9b38d8f8ffe6 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -542,6 +542,16 @@ static inline int qdisc_qlen(const struct Qdisc *q)
return q->q.qlen;
}
+static inline void qdisc_qlen_inc(struct Qdisc *q)
+{
+ WRITE_ONCE(q->q.qlen, q->q.qlen + 1);
+}
+
+static inline void qdisc_qlen_dec(struct Qdisc *q)
+{
+ WRITE_ONCE(q->q.qlen, q->q.qlen - 1);
+}
+
static inline int qdisc_qlen_sum(const struct Qdisc *q)
{
__u32 qlen = q->qstats.qlen;
@@ -549,9 +559,9 @@ static inline int qdisc_qlen_sum(const struct Qdisc *q)
if (qdisc_is_percpu_stats(q)) {
for_each_possible_cpu(i)
- qlen += per_cpu_ptr(q->cpu_qstats, i)->qlen;
+ qlen += READ_ONCE(per_cpu_ptr(q->cpu_qstats, i)->qlen);
} else {
- qlen += q->q.qlen;
+ qlen += READ_ONCE(q->q.qlen);
}
return qlen;
@@ -1068,7 +1078,7 @@ static inline void __qdisc_enqueue_tail(struct sk_buff *skb,
qh->tail = skb;
qh->head = skb;
}
- qh->qlen++;
+ WRITE_ONCE(qh->qlen, qh->qlen + 1);
}
static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
@@ -1086,7 +1096,7 @@ static inline void __qdisc_enqueue_head(struct sk_buff *skb,
if (!qh->head)
qh->tail = skb;
qh->head = skb;
- qh->qlen++;
+ WRITE_ONCE(qh->qlen, qh->qlen + 1);
}
static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh)
@@ -1095,7 +1105,7 @@ static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh)
if (likely(skb != NULL)) {
qh->head = skb->next;
- qh->qlen--;
+ WRITE_ONCE(qh->qlen, qh->qlen - 1);
if (qh->head == NULL)
qh->tail = NULL;
skb->next = NULL;
@@ -1110,7 +1120,7 @@ static inline struct sk_buff *qdisc_dequeue_internal(struct Qdisc *sch, bool dir
skb = __skb_dequeue(&sch->gso_skb);
if (skb) {
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
return skb;
}
@@ -1266,7 +1276,7 @@ static inline struct sk_buff *qdisc_peek_dequeued(struct Qdisc *sch)
__skb_queue_head(&sch->gso_skb, skb);
/* it's still part of the queue */
qdisc_qstats_backlog_inc(sch, skb);
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
}
}
@@ -1283,7 +1293,7 @@ static inline void qdisc_update_stats_at_dequeue(struct Qdisc *sch,
} else {
qdisc_qstats_backlog_dec(sch, skb);
qdisc_bstats_update(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
}
}
@@ -1295,7 +1305,7 @@ static inline void qdisc_update_stats_at_enqueue(struct Qdisc *sch,
this_cpu_add(sch->cpu_qstats->backlog, pkt_len);
} else {
sch->qstats.backlog += pkt_len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
}
}
@@ -1311,7 +1321,7 @@ static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
qdisc_qstats_cpu_qlen_dec(sch);
} else {
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
}
} else {
skb = sch->dequeue(sch);
@@ -1332,7 +1342,7 @@ static inline void __qdisc_reset_queue(struct qdisc_skb_head *qh)
qh->head = NULL;
qh->tail = NULL;
- qh->qlen = 0;
+ WRITE_ONCE(qh->qlen, 0);
}
}
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 6f7847c5536f16e6754954f0a606581e17257361..cefa2d8ac5ec00c78b08b520a11672120d10cdef 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -805,7 +805,7 @@ void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
cl = cops->find(sch, parentid);
cops->qlen_notify(sch, cl);
}
- sch->q.qlen -= n;
+ WRITE_ONCE(sch->q.qlen, sch->q.qlen - n);
sch->qstats.backlog -= len;
__qdisc_qstats_drop(sch, drops);
}
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index d931e8d51f723fdedea9f3f90efceec6e0a070d3..7ab75a52f7d1a46d87fc8f7c099c749a5331ccf6 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1612,7 +1612,7 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
cake_advance_shaper(q, b, skb, now, true);
qdisc_drop_reason(skb, sch, to_free, QDISC_DROP_OVERLIMIT);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
cake_heapify(q, 0);
@@ -1822,7 +1822,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
segs);
flow_queue_add(flow, segs);
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
numsegs++;
slen += segs->len;
q->buffer_used += segs->truesize;
@@ -1861,7 +1861,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
qdisc_tree_reduce_backlog(sch, 1, ack_pkt_len);
consume_skb(ack);
} else {
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
q->buffer_used += skb->truesize;
}
@@ -1987,7 +1987,7 @@ static struct sk_buff *cake_dequeue_one(struct Qdisc *sch)
WRITE_ONCE(b->tin_backlog, b->tin_backlog - len);
sch->qstats.backlog -= len;
q->buffer_used -= skb->truesize;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
if (q->overflow_timeout)
cake_heapify(q, b->overflow_idx[q->cur_flow]);
diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c
index 8c9a0400c8622c652db290796f2dd338eb61799c..a75e58876797952f2218725f6da5cff29f330ae2 100644
--- a/net/sched/sch_cbs.c
+++ b/net/sched/sch_cbs.c
@@ -97,7 +97,7 @@ static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch,
return err;
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
@@ -168,7 +168,7 @@ static struct sk_buff *cbs_child_dequeue(struct Qdisc *sch, struct Qdisc *child)
qdisc_qstats_backlog_dec(sch, skb);
qdisc_bstats_update(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index 2875bcdb18a413075c795665e95f9dbbaac45962..73d3e673dc7b16cf2b9ac1d622da280c2ceb064a 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -123,7 +123,7 @@ static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx,
if (idx == q->tail)
choke_zap_tail_holes(q);
- --sch->q.qlen;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
qdisc_drop(skb, sch, to_free);
@@ -271,7 +271,7 @@ static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (sch->q.qlen < q->limit) {
q->tab[q->tail] = skb;
q->tail = (q->tail + 1) & q->tab_mask;
- ++sch->q.qlen;
+ qdisc_qlen_inc(sch);
qdisc_qstats_backlog_inc(sch, skb);
return NET_XMIT_SUCCESS;
}
@@ -298,7 +298,7 @@ static struct sk_buff *choke_dequeue(struct Qdisc *sch)
skb = q->tab[q->head];
q->tab[q->head] = NULL;
choke_zap_head_holes(q);
- --sch->q.qlen;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
qdisc_bstats_update(sch, skb);
@@ -396,7 +396,7 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt,
}
dropped += qdisc_pkt_len(skb);
qdisc_qstats_backlog_dec(sch, skb);
- --sch->q.qlen;
+ qdisc_qlen_dec(sch);
rtnl_qdisc_drop(skb, sch);
}
qdisc_tree_reduce_backlog(sch, oqlen - sch->q.qlen, dropped);
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index 01335a49e091444747635ee8bc7e22ded504d571..925fa0cfd730ce72e45e8983ba02eb913afb1235 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -366,7 +366,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch,
}
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return err;
}
@@ -399,7 +399,7 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch)
bstats_update(&cl->bstats, skb);
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
diff --git a/net/sched/sch_dualpi2.c b/net/sched/sch_dualpi2.c
index 241e6a46bd00e39820f5ba9dc71d559f205a4de0..c6416f09dddd8f170b92e50fb89377a15773c5bf 100644
--- a/net/sched/sch_dualpi2.c
+++ b/net/sched/sch_dualpi2.c
@@ -415,7 +415,7 @@ static int dualpi2_enqueue_skb(struct sk_buff *skb, struct Qdisc *sch,
dualpi2_skb_cb(skb)->apply_step = skb_apply_step(skb, q);
/* Keep the overall qdisc stats consistent */
- ++sch->q.qlen;
+ qdisc_qlen_inc(sch);
qdisc_qstats_backlog_inc(sch, skb);
++q->packets_in_l;
if (!q->l_head_ts)
@@ -530,7 +530,7 @@ static struct sk_buff *dequeue_packet(struct Qdisc *sch,
qdisc_qstats_backlog_dec(q->l_queue, skb);
/* Keep the global queue size consistent */
- --sch->q.qlen;
+ qdisc_qlen_dec(sch);
q->memory_used -= skb->truesize;
} else if (c_len) {
skb = __qdisc_dequeue_head(&sch->q);
@@ -888,7 +888,7 @@ static int dualpi2_change(struct Qdisc *sch, struct nlattr *opt,
* l_queue on enqueue; qdisc_dequeue_internal()
* handled l_queue, so we further account for sch.
*/
- --sch->q.qlen;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
q->memory_used -= skb->truesize;
rtnl_qdisc_drop(skb, q->l_queue);
diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
index c74d778c32a1eda639650df4d1d103c5338f14e6..ada87a81da6ac4c20e036b5391eb4efe9795ab91 100644
--- a/net/sched/sch_etf.c
+++ b/net/sched/sch_etf.c
@@ -189,7 +189,7 @@ static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
rb_insert_color_cached(&nskb->rbnode, &q->head, leftmost);
qdisc_qstats_backlog_inc(sch, nskb);
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
/* Now we may need to re-arm the qdisc watchdog for the next packet. */
reset_watchdog(sch);
@@ -222,7 +222,7 @@ static void timesortedlist_drop(struct Qdisc *sch, struct sk_buff *skb,
qdisc_qstats_backlog_dec(sch, skb);
qdisc_drop(skb, sch, &to_free);
qdisc_qstats_overlimit(sch);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
}
kfree_skb_list(to_free);
@@ -247,7 +247,7 @@ static void timesortedlist_remove(struct Qdisc *sch, struct sk_buff *skb)
q->last = skb->tstamp;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
}
static struct sk_buff *etf_dequeue_timesortedlist(struct Qdisc *sch)
@@ -426,7 +426,7 @@ static void timesortedlist_clear(struct Qdisc *sch)
rb_erase_cached(&skb->rbnode, &q->head);
rtnl_kfree_skbs(skb, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
}
}
diff --git a/net/sched/sch_ets.c b/net/sched/sch_ets.c
index a4b07b661b7756a675d22c0f84f8f0a713cdb7eb..c817e0a6c14653a35f5ebb9de1a5ccc44d1a2f98 100644
--- a/net/sched/sch_ets.c
+++ b/net/sched/sch_ets.c
@@ -449,7 +449,7 @@ static int ets_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
}
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return err;
}
@@ -458,7 +458,7 @@ ets_qdisc_dequeue_skb(struct Qdisc *sch, struct sk_buff *skb)
{
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index f2edcf872981fd8181dfb97a3bc665fd4a869115..1e34ac136b15cf24742f2810d201420cf763021a 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -497,7 +497,7 @@ static void fq_dequeue_skb(struct Qdisc *sch, struct fq_flow *flow,
fq_erase_head(sch, flow, skb);
skb_mark_not_on_list(skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_bstats_update(sch, skb);
}
@@ -597,7 +597,7 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
flow_queue_add(f, skb);
qdisc_qstats_backlog_inc(sch, skb);
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
@@ -801,7 +801,7 @@ static void fq_reset(struct Qdisc *sch)
struct fq_flow *f;
unsigned int idx;
- sch->q.qlen = 0;
+ WRITE_ONCE(sch->q.qlen, 0);
sch->qstats.backlog = 0;
fq_flow_purge(&q->internal);
diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index ed42ce62a17f1de9516af90533d16b65657f86cd..cae8483fbb0c4f62f28dba4c15b4426485390bcf 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -178,7 +178,7 @@ static unsigned int fq_codel_drop(struct Qdisc *sch, unsigned int max_packets,
q->memory_usage -= mem;
__qdisc_qstats_drop(sch, i);
sch->qstats.backlog -= len;
- sch->q.qlen -= i;
+ WRITE_ONCE(sch->q.qlen, sch->q.qlen - i);
return idx;
}
@@ -215,7 +215,8 @@ static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch,
get_codel_cb(skb)->mem_usage = skb->truesize;
q->memory_usage += get_codel_cb(skb)->mem_usage;
memory_limited = q->memory_usage > q->memory_limit;
- if (++sch->q.qlen <= sch->limit && !memory_limited)
+ qdisc_qlen_inc(sch);
+ if (sch->q.qlen <= sch->limit && !memory_limited)
return NET_XMIT_SUCCESS;
prev_backlog = sch->qstats.backlog;
@@ -266,7 +267,7 @@ static struct sk_buff *dequeue_func(struct codel_vars *vars, void *ctx)
WRITE_ONCE(q->backlogs[flow - q->flows],
q->backlogs[flow - q->flows] - qdisc_pkt_len(skb));
q->memory_usage -= get_codel_cb(skb)->mem_usage;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
sch->qstats.backlog -= qdisc_pkt_len(skb);
}
return skb;
diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c
index 7becbf5362b3165bac4517f32887386b01301612..0a4eca4ab086ebebbdba17784f12370c301bbac6 100644
--- a/net/sched/sch_fq_pie.c
+++ b/net/sched/sch_fq_pie.c
@@ -185,7 +185,7 @@ static int fq_pie_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
q->stats.packets_in++;
q->memory_usage += skb->truesize;
sch->qstats.backlog += pkt_len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
flow_queue_add(sel_flow, skb);
if (list_empty(&sel_flow->flowchain)) {
list_add_tail(&sel_flow->flowchain, &q->new_flows);
@@ -263,7 +263,7 @@ static struct sk_buff *fq_pie_qdisc_dequeue(struct Qdisc *sch)
skb = dequeue_head(flow);
pkt_len = qdisc_pkt_len(skb);
sch->qstats.backlog -= pkt_len;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_bstats_update(sch, skb);
}
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 05c250c483f0cbe8ccaf810558d9465073b72699..7b4a5874ed1f612ed1e16f910df30eadce8330fe 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -118,7 +118,7 @@ static inline struct sk_buff *__skb_dequeue_bad_txq(struct Qdisc *q)
qdisc_qstats_cpu_qlen_dec(q);
} else {
qdisc_qstats_backlog_dec(q, skb);
- q->q.qlen--;
+ qdisc_qlen_dec(q);
}
} else {
skb = SKB_XOFF_MAGIC;
@@ -159,7 +159,7 @@ static inline void qdisc_enqueue_skb_bad_txq(struct Qdisc *q,
qdisc_qstats_cpu_qlen_inc(q);
} else {
qdisc_qstats_backlog_inc(q, skb);
- q->q.qlen++;
+ qdisc_qlen_inc(q);
}
if (lock)
@@ -188,7 +188,7 @@ static inline void dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
} else {
q->qstats.requeues++;
qdisc_qstats_backlog_inc(q, skb);
- q->q.qlen++;
+ qdisc_qlen_inc(q);
}
skb = next;
@@ -294,7 +294,7 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
qdisc_qstats_cpu_qlen_dec(q);
} else {
qdisc_qstats_backlog_dec(q, skb);
- q->q.qlen--;
+ qdisc_qlen_dec(q);
}
} else {
skb = NULL;
@@ -1062,7 +1062,7 @@ void qdisc_reset(struct Qdisc *qdisc)
__skb_queue_purge(&qdisc->gso_skb);
__skb_queue_purge(&qdisc->skb_bad_txq);
- qdisc->q.qlen = 0;
+ WRITE_ONCE(qdisc->q.qlen, 0);
qdisc->qstats.backlog = 0;
}
EXPORT_SYMBOL(qdisc_reset);
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 83b2ca2e37fc82cfebf089e6c0e36f18af939887..e71a565100edf60881ca7542faa408c5bb1a0984 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1561,7 +1561,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
}
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
if (first && !cl_in_el_or_vttree(cl)) {
if (cl->cl_flags & HFSC_RSC)
@@ -1650,7 +1650,7 @@ hfsc_dequeue(struct Qdisc *sch)
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c
index 96021f52d835b56339509565ca03fe796593e231..1e25b75daae2e5de31bd212dfa1f6d7aea927174 100644
--- a/net/sched/sch_hhf.c
+++ b/net/sched/sch_hhf.c
@@ -360,7 +360,7 @@ static unsigned int hhf_drop(struct Qdisc *sch, struct sk_buff **to_free)
if (bucket->head) {
struct sk_buff *skb = dequeue_head(bucket);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
qdisc_drop(skb, sch, to_free);
}
@@ -400,7 +400,8 @@ static int hhf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
}
bucket->deficit = weight * q->quantum;
}
- if (++sch->q.qlen <= sch->limit)
+ qdisc_qlen_inc(sch);
+ if (sch->q.qlen <= sch->limit)
return NET_XMIT_SUCCESS;
prev_backlog = sch->qstats.backlog;
@@ -443,7 +444,7 @@ static struct sk_buff *hhf_dequeue(struct Qdisc *sch)
if (bucket->head) {
skb = dequeue_head(bucket);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
}
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index eb12381795ce1bb0f3b8c5f502e16ad64c4408c8..c22ccd8eae8c73323ccdf425e62857b3b851d74e 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -651,7 +651,7 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
}
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
@@ -951,7 +951,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
ok:
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c
index a0133a7b9d3b09a0d2a6064234c8fdef60dbf955..ec8c91d3fde04e59daec2aecdb14d6bf50715e15 100644
--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c
@@ -143,10 +143,10 @@ EXPORT_SYMBOL_NS_GPL(mq_attach, "NET_SCHED_INTERNAL");
void mq_dump_common(struct Qdisc *sch, struct sk_buff *skb)
{
struct net_device *dev = qdisc_dev(sch);
+ unsigned int qlen = 0;
struct Qdisc *qdisc;
unsigned int ntx;
- sch->q.qlen = 0;
gnet_stats_basic_sync_init(&sch->bstats);
memset(&sch->qstats, 0, sizeof(sch->qstats));
@@ -163,10 +163,11 @@ void mq_dump_common(struct Qdisc *sch, struct sk_buff *skb)
&qdisc->bstats, false);
gnet_stats_add_queue(&sch->qstats, qdisc->cpu_qstats,
&qdisc->qstats);
- sch->q.qlen += qdisc_qlen(qdisc);
+ qlen += qdisc_qlen(qdisc);
spin_unlock_bh(qdisc_lock(qdisc));
}
+ WRITE_ONCE(sch->q.qlen, qlen);
}
EXPORT_SYMBOL_NS_GPL(mq_dump_common, "NET_SCHED_INTERNAL");
diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c
index 002add5ce9e0ab04a6260495d1bec02983c2a204..91a92992cd24ab6c30bf7db2288c08cd493c7bc3 100644
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c
@@ -555,10 +555,11 @@ static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
struct mqprio_sched *priv = qdisc_priv(sch);
struct nlattr *nla = (struct nlattr *)skb_tail_pointer(skb);
struct tc_mqprio_qopt opt = { 0 };
+ unsigned int qlen = 0;
struct Qdisc *qdisc;
unsigned int ntx;
- sch->q.qlen = 0;
+ qlen = 0;
gnet_stats_basic_sync_init(&sch->bstats);
memset(&sch->qstats, 0, sizeof(sch->qstats));
@@ -575,10 +576,11 @@ static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb)
&qdisc->bstats, false);
gnet_stats_add_queue(&sch->qstats, qdisc->cpu_qstats,
&qdisc->qstats);
- sch->q.qlen += qdisc_qlen(qdisc);
+ qlen += qdisc_qlen(qdisc);
spin_unlock_bh(qdisc_lock(qdisc));
}
+ WRITE_ONCE(sch->q.qlen, qlen);
mqprio_qopt_reconstruct(dev, &opt);
opt.hw = priv->hw_offload;
@@ -663,12 +665,12 @@ static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
__acquires(d->lock)
{
if (cl >= TC_H_MIN_PRIORITY) {
- int i;
- __u32 qlen;
- struct gnet_stats_queue qstats = {0};
- struct gnet_stats_basic_sync bstats;
struct net_device *dev = qdisc_dev(sch);
struct netdev_tc_txq tc = dev->tc_to_txq[cl & TC_BITMASK];
+ struct gnet_stats_queue qstats = {0};
+ struct gnet_stats_basic_sync bstats;
+ u32 qlen = 0;
+ int i;
gnet_stats_basic_sync_init(&bstats);
/* Drop lock here it will be reclaimed before touching
@@ -689,11 +691,11 @@ static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
&qdisc->bstats, false);
gnet_stats_add_queue(&qstats, qdisc->cpu_qstats,
&qdisc->qstats);
- sch->q.qlen += qdisc_qlen(qdisc);
+ qlen += qdisc_qlen(qdisc);
spin_unlock_bh(qdisc_lock(qdisc));
}
- qlen = qdisc_qlen(sch) + qstats.qlen;
+ qlen = qlen + qstats.qlen;
/* Reclaim root sleeping lock before completing stats */
if (d->lock)
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index 9f822fee113df6562ddac89092357434547a4599..4e465d11e3d75e36b875b66f8c8087c2e15cdad9 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -76,7 +76,7 @@ multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
ret = qdisc_enqueue(skb, qdisc, to_free);
if (ret == NET_XMIT_SUCCESS) {
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
if (net_xmit_drop_count(ret))
@@ -106,7 +106,7 @@ static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
skb = qdisc->dequeue(qdisc);
if (skb) {
qdisc_bstats_update(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
}
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index bc18e1976b6e07f81f975ceeb35c8b1a5125e8df..57b12cbca45355c69780614fa87aaf37255d64cc 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -416,7 +416,7 @@ static void tfifo_enqueue(struct sk_buff *nskb, struct Qdisc *sch)
rb_insert_color(&nskb->rbnode, &q->t_root);
}
q->t_len++;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
}
/* netem can't properly corrupt a megapacket (like we get from GSO), so instead
@@ -751,19 +751,19 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
if (net_xmit_drop_count(err))
qdisc_qstats_drop(sch);
sch->qstats.backlog -= pkt_len;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_tree_reduce_backlog(sch, 1, pkt_len);
}
goto tfifo_dequeue;
}
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
goto deliver;
}
if (q->qdisc) {
skb = q->qdisc->ops->dequeue(q->qdisc);
if (skb) {
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
goto deliver;
}
}
@@ -776,7 +776,7 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
if (q->qdisc) {
skb = q->qdisc->ops->dequeue(q->qdisc);
if (skb) {
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
goto deliver;
}
}
diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index 9e2b9a490db23d858b27b7fc073b05a06535b05e..fe42ae3d6b696b2fc47f4d397af32e950eeec194 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -86,7 +86,7 @@ prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
ret = qdisc_enqueue(skb, qdisc, to_free);
if (ret == NET_XMIT_SUCCESS) {
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
if (net_xmit_drop_count(ret))
@@ -119,7 +119,7 @@ static struct sk_buff *prio_dequeue(struct Qdisc *sch)
if (skb) {
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
}
diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index 699e45873f86145e96abd0d9ca77a6d0ff763b1b..195c434aae5f7e03d1a1238ed73bb64b3f04e105 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -1152,12 +1152,12 @@ static struct sk_buff *qfq_dequeue(struct Qdisc *sch)
if (!skb)
return NULL;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
skb = agg_dequeue(in_serv_agg, cl, len);
if (!skb) {
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NULL;
}
@@ -1265,7 +1265,7 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
_bstats_update(&cl->bstats, len, gso_segs);
sch->qstats.backlog += len;
- ++sch->q.qlen;
+ qdisc_qlen_inc(sch);
agg = cl->agg;
/* if the class is active, then done here */
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 4d0e44a2e7c664e1599699d21ef482529ee2b119..0719590dfd73b64d21f71ab00621f64ed0eefc89 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -139,7 +139,7 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
ret = qdisc_enqueue(skb, child, to_free);
if (likely(ret == NET_XMIT_SUCCESS)) {
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
} else if (net_xmit_drop_count(ret)) {
WRITE_ONCE(q->stats.pdrop,
q->stats.pdrop + 1);
@@ -166,7 +166,7 @@ static struct sk_buff *red_dequeue(struct Qdisc *sch)
if (skb) {
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
} else {
if (!red_is_idling(&q->vars))
red_start_of_idle_period(&q->vars);
diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c
index d3ee8e5479b35e38b71b0979e78aeadb40eb1655..efd9251c3add317f3b817f08c732fca0c347bf35 100644
--- a/net/sched/sch_sfb.c
+++ b/net/sched/sch_sfb.c
@@ -416,7 +416,7 @@ static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch,
ret = qdisc_enqueue(skb, child, to_free);
if (likely(ret == NET_XMIT_SUCCESS)) {
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
increment_qlen(&cb, q);
} else if (net_xmit_drop_count(ret)) {
WRITE_ONCE(q->stats.childdrop,
@@ -446,7 +446,7 @@ static struct sk_buff *sfb_dequeue(struct Qdisc *sch)
if (skb) {
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
decrement_qlen(skb, q);
}
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index f39822babf88bee9d52cac9f39637d38ec36994f..f9807ee2cf6c72101ce39c4f43bf32c03c0a5f62 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -302,7 +302,7 @@ static unsigned int sfq_drop(struct Qdisc *sch, struct sk_buff **to_free)
len = qdisc_pkt_len(skb);
WRITE_ONCE(slot->backlog, slot->backlog - len);
sfq_dec(q, x);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
qdisc_drop_reason(skb, sch, to_free, QDISC_DROP_OVERLIMIT);
return len;
@@ -456,7 +456,8 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
/* We could use a bigger initial quantum for new flows */
WRITE_ONCE(slot->allot, q->quantum);
}
- if (++sch->q.qlen <= q->limit)
+ qdisc_qlen_inc(sch);
+ if (sch->q.qlen <= q->limit)
return NET_XMIT_SUCCESS;
qlen = slot->qlen;
@@ -497,7 +498,7 @@ sfq_dequeue(struct Qdisc *sch)
skb = slot_dequeue_head(slot);
sfq_dec(q, a);
qdisc_bstats_update(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
WRITE_ONCE(slot->backlog, slot->backlog - qdisc_pkt_len(skb));
/* Is the slot empty? */
@@ -596,7 +597,7 @@ static void sfq_rehash(struct Qdisc *sch)
WRITE_ONCE(slot->allot, q->quantum);
}
}
- sch->q.qlen -= dropped;
+ WRITE_ONCE(sch->q.qlen, sch->q.qlen - dropped);
qdisc_tree_reduce_backlog(sch, dropped, drop_len);
}
diff --git a/net/sched/sch_skbprio.c b/net/sched/sch_skbprio.c
index f485f62ab721ab8cde21230c60514708fb479982..52abfb4015a36408046d96b349497419ab5dacf8 100644
--- a/net/sched/sch_skbprio.c
+++ b/net/sched/sch_skbprio.c
@@ -93,7 +93,7 @@ static int skbprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (prio < q->lowest_prio)
q->lowest_prio = prio;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
@@ -145,7 +145,7 @@ static struct sk_buff *skbprio_dequeue(struct Qdisc *sch)
if (unlikely(!skb))
return NULL;
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_qstats_backlog_dec(sch, skb);
qdisc_bstats_update(sch, skb);
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 71b690e1974dad8fbab7e12998e03f86a0847a98..d6b981e5df11cba060c9c92212479c0d5a058f5b 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -574,7 +574,7 @@ static int taprio_enqueue_one(struct sk_buff *skb, struct Qdisc *sch,
}
qdisc_qstats_backlog_inc(sch, skb);
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return qdisc_enqueue(skb, child, to_free);
}
@@ -755,7 +755,7 @@ static struct sk_buff *taprio_dequeue_from_txq(struct Qdisc *sch, int txq,
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
return skb;
}
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index f2340164f579a25431979e12ec3d23ab828edd16..25edf11a7d671fe63878b0995998c5920b86ef74 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -231,7 +231,7 @@ static int tbf_segment(struct sk_buff *skb, struct Qdisc *sch,
len += seg_len;
}
}
- sch->q.qlen += nb;
+ WRITE_ONCE(sch->q.qlen, sch->q.qlen + nb);
sch->qstats.backlog += len;
if (nb > 0) {
qdisc_tree_reduce_backlog(sch, 1 - nb, prev_len - len);
@@ -264,7 +264,7 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
}
sch->qstats.backlog += len;
- sch->q.qlen++;
+ qdisc_qlen_inc(sch);
return NET_XMIT_SUCCESS;
}
@@ -309,7 +309,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
q->tokens = toks;
q->ptokens = ptoks;
qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
+ qdisc_qlen_dec(sch);
qdisc_bstats_update(sch, skb);
return skb;
}
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index ec4039a201a2c2c502bc649fa5f6a0e4feee8fd5..e7bbc9e5174d0e76252e9091963ddf4fc8fa5557 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -107,7 +107,7 @@ teql_dequeue(struct Qdisc *sch)
} else {
qdisc_bstats_update(sch, skb);
}
- sch->q.qlen = dat->q.qlen + q->q.qlen;
+ WRITE_ONCE(sch->q.qlen, dat->q.qlen + READ_ONCE(q->q.qlen));
return skb;
}
--
2.54.0.563.g4f69b47b94-goog
next prev parent reply other threads:[~2026-05-10 9:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-10 9:14 [PATCH v2 net-next 0/8] net/sched: prepare lockless qdisc dumps Eric Dumazet
2026-05-10 9:14 ` [PATCH v2 net-next 1/8] net/sched: add READ_ONCE() in gnet_stats_add_queue[_cpu] Eric Dumazet
2026-05-10 9:14 ` Eric Dumazet [this message]
2026-05-10 9:14 ` [PATCH v2 net-next 3/8] net/sched: annotate data-races around sch->qstats.backlog Eric Dumazet
2026-05-10 9:14 ` [PATCH v2 net-next 4/8] net/sched: add qdisc_qlen_lockless() helper Eric Dumazet
2026-05-10 9:14 ` [PATCH v2 net-next 5/8] net/sched: add const qualifiers to gnet_stats helpers Eric Dumazet
2026-05-10 9:14 ` [PATCH v2 net-next 6/8] net/sched: mq: no longer acquire qdisc spinlocks in dump operations Eric Dumazet
2026-05-10 9:14 ` [PATCH v2 net-next 7/8] net/sched: mq_prio: no longer acquire qdisc spinlocks in mqprio_dump() Eric Dumazet
2026-05-10 9:14 ` [PATCH v2 net-next 8/8] net/sched: mq_prio: no longer acquire qdisc spinlocks in mqprio_dump_class_stats() Eric Dumazet
2026-05-10 9:31 ` [PATCH v2 net-next 0/8] net/sched: prepare lockless qdisc dumps Toke Høiland-Jørgensen
2026-05-12 1:48 ` patchwork-bot+netdevbpf
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