[PATCH net-next v3 04/10] net: sched: add helper function to take reference to Qdisc
From: Vlad Buslov <hidden>
Date: 2018-09-24 22:26:20
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted> Acked-by: Jiri Pirko <redacted> --- 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 091b40c198ff..43b17f82d8ee 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)
--
2.7.5