From 6e1c7a08c846ddaf938b015e8031012c07ce4814 Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Mon, 24 Sep 2018 19:22:52 +0300 Subject: [PATCH] net: sched: add helper function to take reference to Qdisc Implement function to take reference to Qdisc that relies on rcu read lock instead of rtnl mutex. Function only takes reference to Qdisc if reference counter isn't zero. Intended to be used by unlocked cls API. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/sch_generic.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 091b40c198ff8..43b17f82d8eeb 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -115,6 +115,19 @@ static inline void qdisc_refcount_inc(struct Qdisc *qdisc) refcount_inc(&qdisc->refcnt); } +/* Intended to be used by unlocked users, when concurrent qdisc release is + * possible. + */ + +static inline struct Qdisc *qdisc_refcount_inc_nz(struct Qdisc *qdisc) +{ + if (qdisc->flags & TCQ_F_BUILTIN) + return qdisc; + if (refcount_inc_not_zero(&qdisc->refcnt)) + return qdisc; + return NULL; +} + static inline bool qdisc_is_running(struct Qdisc *qdisc) { if (qdisc->flags & TCQ_F_NOLOCK) -- 2.39.5