net/sched: add READ_ONCE() in gnet_stats_add_queue[_cpu]

Stats are read locklessly, add READ_ONCE() to prevent load-tearing.

Write side will be handled in separate patches.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Link: https://patch.msgid.link/20260510091455.4039245-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
index b71ccaec0991461333dbe465ee619bca4a06e75b..1a2380e74272de8eaf3d4ef453e56105a31e9edf 100644 (file)
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -345,11 +345,11 @@ static void gnet_stats_add_queue_cpu(struct gnet_stats_queue *qstats,
        for_each_possible_cpu(i) {
                const struct gnet_stats_queue *qcpu = per_cpu_ptr(q, i);
 
-               qstats->qlen += qcpu->qlen;
-               qstats->backlog += qcpu->backlog;
-               qstats->drops += qcpu->drops;
-               qstats->requeues += qcpu->requeues;
-               qstats->overlimits += qcpu->overlimits;
+               qstats->qlen += READ_ONCE(qcpu->qlen);
+               qstats->backlog += READ_ONCE(qcpu->backlog);
+               qstats->drops += READ_ONCE(qcpu->drops);
+               qstats->requeues += READ_ONCE(qcpu->requeues);
+               qstats->overlimits += READ_ONCE(qcpu->overlimits);
        }
 }
 
@@ -360,11 +360,11 @@ void gnet_stats_add_queue(struct gnet_stats_queue *qstats,
        if (cpu) {
                gnet_stats_add_queue_cpu(qstats, cpu);
        } else {
-               qstats->qlen += q->qlen;
-               qstats->backlog += q->backlog;
-               qstats->drops += q->drops;
-               qstats->requeues += q->requeues;
-               qstats->overlimits += q->overlimits;
+               qstats->qlen += READ_ONCE(q->qlen);
+               qstats->backlog += READ_ONCE(q->backlog);
+               qstats->drops += READ_ONCE(q->drops);
+               qstats->requeues += READ_ONCE(q->requeues);
+               qstats->overlimits += READ_ONCE(q->overlimits);
        }
 }
 EXPORT_SYMBOL(gnet_stats_add_queue);