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>

5 files changed, 25 insertions, 9 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index b1d2cfea89c5..ef8a7e2e12e7 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -217,6 +217,14 @@ static inline spinlock_t *qdisc_root_lock(struct Qdisc *qdisc)
         return qdisc_lock(root);
 }
 
+static inline spinlock_t *qdisc_root_sleeping_lock(struct Qdisc *qdisc)
+{
+        struct Qdisc *root = qdisc_root_sleeping(qdisc);
+
+        ASSERT_RTNL();
+        return qdisc_lock(root);
+}
+
 static inline struct net_device *qdisc_dev(struct Qdisc *qdisc)
 {
         return qdisc->dev_queue->dev;
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;
 }
 
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 8fa90d68ec6d..9b720adedead 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -1839,7 +1839,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
 
                 if (tca[TCA_RATE])
                         gen_replace_estimator(&cl->bstats, &cl->rate_est,
-                                              qdisc_root_lock(sch),
+                                              qdisc_root_sleeping_lock(sch),
                                               tca[TCA_RATE]);
                 return 0;
         }
@@ -1930,7 +1930,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
 
         if (tca[TCA_RATE])
                 gen_new_estimator(&cl->bstats, &cl->rate_est,
-                                  qdisc_root_lock(sch), tca[TCA_RATE]);
+                                  qdisc_root_sleeping_lock(sch), tca[TCA_RATE]);
 
         *arg = (unsigned long)cl;
         return 0;
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index c2b8d9cce3d2..c1e77da8cd09 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1045,7 +1045,7 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 
                 if (tca[TCA_RATE])
                         gen_replace_estimator(&cl->bstats, &cl->rate_est,
-                                              qdisc_root_lock(sch),
+                                              qdisc_root_sleeping_lock(sch),
                                               tca[TCA_RATE]);
                 return 0;
         }
@@ -1104,7 +1104,7 @@ hfsc_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 
         if (tca[TCA_RATE])
                 gen_new_estimator(&cl->bstats, &cl->rate_est,
-                                  qdisc_root_lock(sch), tca[TCA_RATE]);
+                                  qdisc_root_sleeping_lock(sch), tca[TCA_RATE]);
         *arg = (unsigned long)cl;
         return 0;
 }
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 0df0df202ed0..97d4761cc31e 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1372,7 +1372,7 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
                         goto failure;
 
                 gen_new_estimator(&cl->bstats, &cl->rate_est,
-                                  qdisc_root_lock(sch),
+                                  qdisc_root_sleeping_lock(sch),
                                   tca[TCA_RATE] ? : &est.nla);
                 cl->refcnt = 1;
                 cl->children = 0;
@@ -1427,7 +1427,7 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
         } else {
                 if (tca[TCA_RATE])
                         gen_replace_estimator(&cl->bstats, &cl->rate_est,
-                                              qdisc_root_lock(sch),
+                                              qdisc_root_sleeping_lock(sch),
                                               tca[TCA_RATE]);
                 sch_tree_lock(sch);
         }