diff options
| author | Vlad Buslov <vladbu@mellanox.com> | 2021-12-10 10:47:27 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-14 10:18:04 +0100 |
| commit | f602ed9f8574512e7ea1ab65c3db7ba71053bf27 (patch) | |
| tree | ed454e606d35f221b917385923d18a19d80d17f6 /net | |
| parent | 92833e8b5db6c209e9311ac8c6a44d3bf1856659 (diff) | |
net: sched: extend Qdisc with rcu
[ Upstream commit 3a7d0d07a386716b459b00783b11a8211cefcc0f ]
Currently, Qdisc API functions assume that users have rtnl lock taken. To
implement rtnl unlocked classifiers update interface, Qdisc API must be
extended with functions that do not require rtnl lock.
Extend Qdisc structure with rcu. Implement special version of put function
qdisc_put_unlocked() that is called without rtnl lock taken. This function
only takes rtnl lock if Qdisc reference counter reached zero and is
intended to be used as optimization.
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[Lee: Sent to Stable]
Link: https://syzkaller.appspot.com/bug?id=d7e411c5472dd5da33d8cc921ccadc747743a568
Reported-by: syzbot+5f229e48cccc804062c0@syzkaller.appspotmail.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/sch_api.c | 18 | ||||
| -rw-r--r-- | net/sched/sch_generic.c | 25 |
2 files changed, 42 insertions, 1 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 60f40a396a03..af035431bec6 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -315,6 +315,24 @@ out: return q; } +struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle) +{ + struct netdev_queue *nq; + struct Qdisc *q; + + if (!handle) + return NULL; + q = qdisc_match_from_root(dev->qdisc, handle); + if (q) + goto out; + + nq = dev_ingress_queue_rcu(dev); + if (nq) + q = qdisc_match_from_root(nq->qdisc_sleeping, handle); +out: + return q; +} + static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid) { unsigned long cl; diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 6fee2731b4c2..80498c22d001 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -958,6 +958,13 @@ void qdisc_free(struct Qdisc *qdisc) kfree((char *) qdisc - qdisc->padded); } +void qdisc_free_cb(struct rcu_head *head) +{ + struct Qdisc *q = container_of(head, struct Qdisc, rcu); + + qdisc_free(q); +} + static void qdisc_destroy(struct Qdisc *qdisc) { const struct Qdisc_ops *ops; @@ -991,7 +998,7 @@ static void qdisc_destroy(struct Qdisc *qdisc) kfree_skb_list(skb); } - qdisc_free(qdisc); + call_rcu(&qdisc->rcu, qdisc_free_cb); } void qdisc_put(struct Qdisc *qdisc) @@ -1004,6 +1011,22 @@ void qdisc_put(struct Qdisc *qdisc) } EXPORT_SYMBOL(qdisc_put); +/* Version of qdisc_put() that is called with rtnl mutex unlocked. + * Intended to be used as optimization, this function only takes rtnl lock if + * qdisc reference counter reached zero. + */ + +void qdisc_put_unlocked(struct Qdisc *qdisc) +{ + if (qdisc->flags & TCQ_F_BUILTIN || + !refcount_dec_and_rtnl_lock(&qdisc->refcnt)) + return; + + qdisc_destroy(qdisc); + rtnl_unlock(); +} +EXPORT_SYMBOL(qdisc_put_unlocked); + /* Attach toplevel qdisc to device queue. */ struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue, struct Qdisc *qdisc) |