pkt_sched: Fix gen_estimator locks

While passing a qdisc root lock to gen_new_estimator() and
gen_replace_estimator() dev could be deactivated or even before
grafting proper root qdisc as qdisc_sleeping (e.g. qdisc_create), so
using qdisc_root_lock() is not enough. This patch adds
qdisc_root_sleeping_lock() for this, plus additional checks, where
necessary.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index ad9cda1b8c0a..506b709510b6 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -830,9 +830,16 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
                         sch->stab = stab;
                 }
                 if (tca[TCA_RATE]) {
+                        spinlock_t *root_lock;
+
+                        if ((sch->parent != TC_H_ROOT) &&
+                            !(sch->flags & TCQ_F_INGRESS))
+                                root_lock = qdisc_root_sleeping_lock(sch);
+                        else
+                                root_lock = qdisc_lock(sch);
+
                         err = gen_new_estimator(&sch->bstats, &sch->rate_est,
-                                                qdisc_root_lock(sch),
-                                                tca[TCA_RATE]);
+                                                root_lock, tca[TCA_RATE]);
                         if (err) {
                                 /*
                                  * Any broken qdiscs that would require
@@ -884,7 +891,8 @@ static int qdisc_change(struct Qdisc *sch, struct nlattr **tca)
 
         if (tca[TCA_RATE])
                 gen_replace_estimator(&sch->bstats, &sch->rate_est,
-                                      qdisc_root_lock(sch), tca[TCA_RATE]);
+                                      qdisc_root_sleeping_lock(sch),
+                                      tca[TCA_RATE]);
         return 0;
 }