Commit ca1e4ab1 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Jakub Kicinski
Browse files

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: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: default avatarTariq Toukan <tariqt@nvidia.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 04a88637

include/net/sch_generic.h

+10 −4
Original line number Diff line number Diff line
@@ -552,13 +552,19 @@ 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)

{

	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)

{

	if (q->flags & TCQ_F_MQROOT)

		spin_unlock_bh(qdisc_lock(q));

	else

		spin_unlock_bh(qdisc_root_sleeping_lock(q));

}