1 files changed, 27 insertions, 36 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index f74a097f54ae..d7c767b861a4 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -25,6 +25,7 @@
 #include <linux/hrtimer.h>
 #include <linux/slab.h>
 #include <linux/hashtable.h>
+#include <linux/bpf.h>
 
 #include <net/netdev_lock.h>
 #include <net/net_namespace.h>
@@ -207,7 +208,7 @@ static struct Qdisc_ops *qdisc_lookup_default(const char *name)
 
 	for (q = qdisc_base; q; q = q->next) {
 		if (!strcmp(name, q->id)) {
-			if (!try_module_get(q->owner))
+			if (!bpf_try_module_get(q, q->owner))
 				q = NULL;
 			break;
 		}
@@ -237,7 +238,7 @@ int qdisc_set_default(const char *name)
 
 	if (ops) {
 		/* Set new default */
-		module_put(default_qdisc_ops->owner);
+		bpf_module_put(default_qdisc_ops, default_qdisc_ops->owner);
 		default_qdisc_ops = ops;
 	}
 	write_unlock(&qdisc_mod_lock);
@@ -335,17 +336,22 @@ out:
 	return q;
 }
 
-static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
+static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid,
+				struct netlink_ext_ack *extack)
 {
 	unsigned long cl;
 	const struct Qdisc_class_ops *cops = p->ops->cl_ops;
 
-	if (cops == NULL)
-		return NULL;
+	if (cops == NULL) {
+		NL_SET_ERR_MSG(extack, "Parent qdisc is not classful");
+		return ERR_PTR(-EOPNOTSUPP);
+	}
 	cl = cops->find(p, classid);
 
-	if (cl == 0)
-		return NULL;
+	if (cl == 0) {
+		NL_SET_ERR_MSG(extack, "Specified class not found");
+		return ERR_PTR(-ENOENT);
+	}
 	return cops->leaf(p, cl);
 }
 
@@ -359,7 +365,7 @@ static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
 		read_lock(&qdisc_mod_lock);
 		for (q = qdisc_base; q; q = q->next) {
 			if (nla_strcmp(kind, q->id) == 0) {
-				if (!try_module_get(q->owner))
+				if (!bpf_try_module_get(q, q->owner))
 					q = NULL;
 				break;
 			}
@@ -595,16 +601,6 @@ out:
 	qdisc_skb_cb(skb)->pkt_len = pkt_len;
 }
 
-void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
-{
-	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
-		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
-			txt, qdisc->ops->id, qdisc->handle >> 16);
-		qdisc->flags |= TCQ_F_WARN_NONWC;
-	}
-}
-EXPORT_SYMBOL(qdisc_warn_nonwc);
-
 static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
 {
 	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
@@ -779,15 +775,12 @@ static u32 qdisc_alloc_handle(struct net_device *dev)
 
 void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
 {
-	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
 	const struct Qdisc_class_ops *cops;
 	unsigned long cl;
 	u32 parentid;
 	bool notify;
 	int drops;
 
-	if (n == 0 && len == 0)
-		return;
 	drops = max_t(int, n, 0);
 	rcu_read_lock();
 	while ((parentid = sch->parent)) {
@@ -796,17 +789,8 @@ void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
 
 		if (sch->flags & TCQ_F_NOPARENT)
 			break;
-		/* Notify parent qdisc only if child qdisc becomes empty.
-		 *
-		 * If child was empty even before update then backlog
-		 * counter is screwed and we skip notification because
-		 * parent class is already passive.
-		 *
-		 * If the original child was offloaded then it is allowed
-		 * to be seem as empty, so the parent is notified anyway.
-		 */
-		notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
-						       !qdisc_is_offloaded);
+		/* Notify parent qdisc only if child qdisc becomes empty. */
+		notify = !sch->q.qlen;
 		/* TODO: perform the search on a per txq basis */
 		sch = qdisc_lookup_rcu(qdisc_dev(sch), TC_H_MAJ(parentid));
 		if (sch == NULL) {
@@ -815,6 +799,9 @@ void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
 		}
 		cops = sch->ops->cl_ops;
 		if (notify && cops->qlen_notify) {
+			/* Note that qlen_notify must be idempotent as it may get called
+			 * multiple times.
+			 */
 			cl = cops->find(sch, parentid);
 			cops->qlen_notify(sch, cl);
 		}
@@ -1370,7 +1357,7 @@ err_out3:
 	netdev_put(dev, &sch->dev_tracker);
 	qdisc_free(sch);
 err_out2:
-	module_put(ops->owner);
+	bpf_module_put(ops, ops->owner);
 err_out:
 	*errp = err;
 	return NULL;
@@ -1498,7 +1485,7 @@ static int __tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
 					NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
 					return -ENOENT;
 				}
-				q = qdisc_leaf(p, clid);
+				q = qdisc_leaf(p, clid, extack);
 			} else if (dev_ingress_queue(dev)) {
 				q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping);
 			}
@@ -1509,6 +1496,8 @@ static int __tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
 			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
 			return -ENOENT;
 		}
+		if (IS_ERR(q))
+			return PTR_ERR(q);
 
 		if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
 			NL_SET_ERR_MSG(extack, "Invalid handle");
@@ -1610,7 +1599,9 @@ static int __tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
 					NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
 					return -ENOENT;
 				}
-				q = qdisc_leaf(p, clid);
+				q = qdisc_leaf(p, clid, extack);
+				if (IS_ERR(q))
+					return PTR_ERR(q);
 			} else if (dev_ingress_queue_create(dev)) {
 				q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping);
 			}
@@ -1782,7 +1773,7 @@ static void request_qdisc_module(struct nlattr *kind)
 
 	ops = qdisc_lookup_ops(kind);
 	if (ops) {
-		module_put(ops->owner);
+		bpf_module_put(ops, ops->owner);
 		return;
 	}