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From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
Date: Sat, 16 Oct 2021 10:49:08 +0200
Subject: [PATCH 7/9] net: sched: Use _bstats_update/set() instead of raw
writes
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.15/older/patches-5.15.3-rt21.tar.xz
The Qdisc::running sequence counter, used to protect Qdisc::bstats reads
from parallel writes, is in the process of being removed. Qdisc::bstats
read/writes will synchronize using an internal u64_stats sync point
instead.
Modify all bstats writes to use _bstats_update(). This ensures that
the internal u64_stats sync point is always acquired and released as
appropriate.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/gen_stats.c | 9 +++++----
net/sched/sch_cbq.c | 3 +--
net/sched/sch_gred.c | 7 ++++---
net/sched/sch_htb.c | 25 +++++++++++++++----------
net/sched/sch_qfq.c | 3 +--
5 files changed, 26 insertions(+), 21 deletions(-)
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -126,6 +126,7 @@ EXPORT_SYMBOL(gnet_stats_basic_packed_in
static void gnet_stats_add_basic_cpu(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu)
{
+ u64 t_bytes = 0, t_packets = 0;
int i;
for_each_possible_cpu(i) {
@@ -139,9 +140,10 @@ static void gnet_stats_add_basic_cpu(str
packets = bcpu->bstats.packets;
} while (u64_stats_fetch_retry_irq(&bcpu->syncp, start));
- bstats->bytes += bytes;
- bstats->packets += packets;
+ t_bytes += bytes;
+ t_packets += packets;
}
+ _bstats_update(bstats, t_bytes, t_packets);
}
void gnet_stats_add_basic(const seqcount_t *running,
@@ -164,8 +166,7 @@ void gnet_stats_add_basic(const seqcount
packets = b->packets;
} while (running && read_seqcount_retry(running, seq));
- bstats->bytes += bytes;
- bstats->packets += packets;
+ _bstats_update(bstats, bytes, packets);
}
EXPORT_SYMBOL(gnet_stats_add_basic);
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -565,8 +565,7 @@ cbq_update(struct cbq_sched_data *q)
long avgidle = cl->avgidle;
long idle;
- cl->bstats.packets++;
- cl->bstats.bytes += len;
+ _bstats_update(&cl->bstats, len, 1);
/*
* (now - last) is total time between packet right edges.
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -353,6 +353,7 @@ static int gred_offload_dump_stats(struc
{
struct gred_sched *table = qdisc_priv(sch);
struct tc_gred_qopt_offload *hw_stats;
+ u64 bytes = 0, packets = 0;
unsigned int i;
int ret;
@@ -381,15 +382,15 @@ static int gred_offload_dump_stats(struc
table->tab[i]->bytesin += hw_stats->stats.bstats[i].bytes;
table->tab[i]->backlog += hw_stats->stats.qstats[i].backlog;
- _bstats_update(&sch->bstats,
- hw_stats->stats.bstats[i].bytes,
- hw_stats->stats.bstats[i].packets);
+ bytes += hw_stats->stats.bstats[i].bytes;
+ packets += hw_stats->stats.bstats[i].packets;
sch->qstats.qlen += hw_stats->stats.qstats[i].qlen;
sch->qstats.backlog += hw_stats->stats.qstats[i].backlog;
sch->qstats.drops += hw_stats->stats.qstats[i].drops;
sch->qstats.requeues += hw_stats->stats.qstats[i].requeues;
sch->qstats.overlimits += hw_stats->stats.qstats[i].overlimits;
}
+ _bstats_update(&sch->bstats, bytes, packets);
kfree(hw_stats);
return ret;
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1308,6 +1308,7 @@ static int htb_dump_class(struct Qdisc *
static void htb_offload_aggregate_stats(struct htb_sched *q,
struct htb_class *cl)
{
+ u64 bytes = 0, packets = 0;
struct htb_class *c;
unsigned int i;
@@ -1323,14 +1324,15 @@ static void htb_offload_aggregate_stats(
if (p != cl)
continue;
- cl->bstats.bytes += c->bstats_bias.bytes;
- cl->bstats.packets += c->bstats_bias.packets;
+ bytes += c->bstats_bias.bytes;
+ packets += c->bstats_bias.packets;
if (c->level == 0) {
- cl->bstats.bytes += c->leaf.q->bstats.bytes;
- cl->bstats.packets += c->leaf.q->bstats.packets;
+ bytes += c->leaf.q->bstats.bytes;
+ packets += c->leaf.q->bstats.packets;
}
}
}
+ _bstats_update(&cl->bstats, bytes, packets);
}
static int
@@ -1358,8 +1360,9 @@ htb_dump_class_stats(struct Qdisc *sch,
cl->bstats = cl->leaf.q->bstats;
else
gnet_stats_basic_packed_init(&cl->bstats);
- cl->bstats.bytes += cl->bstats_bias.bytes;
- cl->bstats.packets += cl->bstats_bias.packets;
+ _bstats_update(&cl->bstats,
+ cl->bstats_bias.bytes,
+ cl->bstats_bias.packets);
} else {
htb_offload_aggregate_stats(q, cl);
}
@@ -1578,8 +1581,9 @@ static int htb_destroy_class_offload(str
WARN_ON(old != q);
if (cl->parent) {
- cl->parent->bstats_bias.bytes += q->bstats.bytes;
- cl->parent->bstats_bias.packets += q->bstats.packets;
+ _bstats_update(&cl->parent->bstats_bias,
+ q->bstats.bytes,
+ q->bstats.packets);
}
offload_opt = (struct tc_htb_qopt_offload) {
@@ -1925,8 +1929,9 @@ static int htb_change_class(struct Qdisc
htb_graft_helper(dev_queue, old_q);
goto err_kill_estimator;
}
- parent->bstats_bias.bytes += old_q->bstats.bytes;
- parent->bstats_bias.packets += old_q->bstats.packets;
+ _bstats_update(&parent->bstats_bias,
+ old_q->bstats.bytes,
+ old_q->bstats.packets);
qdisc_put(old_q);
}
new_q = qdisc_create_dflt(dev_queue, &pfifo_qdisc_ops,
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -1235,8 +1235,7 @@ static int qfq_enqueue(struct sk_buff *s
return err;
}
- cl->bstats.bytes += len;
- cl->bstats.packets += gso_segs;
+ _bstats_update(&cl->bstats, len, gso_segs);
sch->qstats.backlog += len;
++sch->q.qlen;
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