From ca1e4ab199933e1af3f9a86d31060b7f9181c3fc Mon Sep 17 00:00:00 2001 From: Maxim Mikityanskiy Date: Tue, 19 Jan 2021 14:08:11 +0200 Subject: [PATCH] net: sched: Add multi-queue support to sch_tree_lock The existing qdiscs that set TCQ_F_MQROOT don't use sch_tree_lock. However, hardware-offloaded HTB will start setting this flag while also using sch_tree_lock. The current implementation of sch_tree_lock basically locks on qdisc->dev_queue->qdisc, and it works fine when the tree is attached to some queue. However, it's not the case for MQROOT qdiscs: such a qdisc is the root itself, and its dev_queue just points to queue 0, while not actually being used, because there are real per-queue qdiscs. This patch changes the logic of sch_tree_lock and sch_tree_unlock to lock the qdisc itself if it's the MQROOT. Signed-off-by: Maxim Mikityanskiy Reviewed-by: Tariq Toukan Signed-off-by: Jakub Kicinski --- include/net/sch_generic.h | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index e7bee99aebce4..2969190105523 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -552,14 +552,20 @@ static inline struct net_device *qdisc_dev(const struct Qdisc *qdisc) return qdisc->dev_queue->dev; } -static inline void sch_tree_lock(const struct Qdisc *q) +static inline void sch_tree_lock(struct Qdisc *q) { - spin_lock_bh(qdisc_root_sleeping_lock(q)); + if (q->flags & TCQ_F_MQROOT) + spin_lock_bh(qdisc_lock(q)); + else + spin_lock_bh(qdisc_root_sleeping_lock(q)); } -static inline void sch_tree_unlock(const struct Qdisc *q) +static inline void sch_tree_unlock(struct Qdisc *q) { - spin_unlock_bh(qdisc_root_sleeping_lock(q)); + if (q->flags & TCQ_F_MQROOT) + spin_unlock_bh(qdisc_lock(q)); + else + spin_unlock_bh(qdisc_root_sleeping_lock(q)); } extern struct Qdisc noop_qdisc;