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Commit da1d3240 authored by Vlad Buslov's avatar Vlad Buslov Committed by Greg Kroah-Hartman
Browse files

net: sched: add helper function to take reference to Qdisc 



[ Upstream commit 9d7e82cec35c027756ec97e274f878251f271181 ]

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: default avatarVlad Buslov <vladbu@mellanox.com>
Acked-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
[Lee: Sent to Stable]
Link: https://syzkaller.appspot.com/bug?id=d7e411c5472dd5da33d8cc921ccadc747743a568


Reported-by: default avatar <syzbot+5f229e48cccc804062c0@syzkaller.appspotmail.com>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f602ed9f

include/net/sch_generic.h

+13 −0
Original line number Diff line number Diff line
@@ -118,6 +118,19 @@ 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)