net: sched: rename qdisc_destroy() to qdisc_put()

Current implementation of qdisc_destroy() decrements Qdisc reference
counter and only actually destroy Qdisc if reference counter value reached
zero. Rename qdisc_destroy() to qdisc_put() in order for it to better
describe the way in which this function currently implemented and used.

Extract code that deallocates Qdisc into new private qdisc_destroy()
function. It is intended to be shared between regular qdisc_put() and its
unlocked version that is introduced in next patch in this series.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: w1ldptr

include/net/sch_generic.h

@@ -554,7 +554,7 @@ void dev_deactivate_many(struct list_head *head);
 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
 			      struct Qdisc *qdisc);
 void qdisc_reset(struct Qdisc *qdisc);
-void qdisc_destroy(struct Qdisc *qdisc);
+void qdisc_put(struct Qdisc *qdisc);
 void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, unsigned int n,
 			       unsigned int len);
 struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,

net/sched/sch_api.c

@@ -920,7 +920,7 @@ static void notify_and_destroy(struct net *net, struct sk_buff *skb,
 		qdisc_notify(net, skb, n, clid, old, new);
 
 	if (old)
-		qdisc_destroy(old);
+		qdisc_put(old);
 }
 
 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
@@ -973,7 +973,7 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
 				qdisc_refcount_inc(new);
 
 			if (!ingress)
-				qdisc_destroy(old);
+				qdisc_put(old);
 		}
 
 skip:
@@ -1561,7 +1561,7 @@ static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
 	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
 	if (err) {
 		if (q)
-			qdisc_destroy(q);
+			qdisc_put(q);
 		return err;
 	}
 

net/sched/sch_atm.c

@@ -150,7 +150,7 @@ static void atm_tc_put(struct Qdisc *sch, unsigned long cl)
 	pr_debug("atm_tc_put: destroying\n");
 	list_del_init(&flow->list);
 	pr_debug("atm_tc_put: qdisc %p\n", flow->q);
-	qdisc_destroy(flow->q);
+	qdisc_put(flow->q);
 	tcf_block_put(flow->block);
 	if (flow->sock) {
 		pr_debug("atm_tc_put: f_count %ld\n",

net/sched/sch_cbq.c

@@ -1418,7 +1418,7 @@ static void cbq_destroy_class(struct Qdisc *sch, struct cbq_class *cl)
 	WARN_ON(cl->filters);
 
 	tcf_block_put(cl->block);
-	qdisc_destroy(cl->q);
+	qdisc_put(cl->q);
 	qdisc_put_rtab(cl->R_tab);
 	gen_kill_estimator(&cl->rate_est);
 	if (cl != &q->link)

net/sched/sch_cbs.c

@@ -379,7 +379,7 @@ static void cbs_destroy(struct Qdisc *sch)
 	cbs_disable_offload(dev, q);
 
 	if (q->qdisc)
-		qdisc_destroy(q->qdisc);
+		qdisc_put(q->qdisc);
 }
 
 static int cbs_dump(struct Qdisc *sch, struct sk_buff *skb)

net/sched/sch_drr.c

@@ -134,7 +134,7 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 					    tca[TCA_RATE]);
 		if (err) {
 			NL_SET_ERR_MSG(extack, "Failed to replace estimator");
-			qdisc_destroy(cl->qdisc);
+			qdisc_put(cl->qdisc);
 			kfree(cl);
 			return err;
 		}
@@ -153,7 +153,7 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
 static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
 {
 	gen_kill_estimator(&cl->rate_est);
-	qdisc_destroy(cl->qdisc);
+	qdisc_put(cl->qdisc);
 	kfree(cl);
 }
 

net/sched/sch_dsmark.c

@@ -412,7 +412,7 @@ static void dsmark_destroy(struct Qdisc *sch)
 	pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
 
 	tcf_block_put(p->block);
-	qdisc_destroy(p->q);
+	qdisc_put(p->q);
 	if (p->mv != p->embedded)
 		kfree(p->mv);
 }

net/sched/sch_fifo.c

@@ -177,7 +177,7 @@ struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
 	if (q) {
 		err = fifo_set_limit(q, limit);
 		if (err < 0) {
-			qdisc_destroy(q);
+			qdisc_put(q);
 			q = NULL;
 		}
 	}

net/sched/sch_generic.c

@@ -901,7 +901,7 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue,
 	if (!ops->init || ops->init(sch, NULL, extack) == 0)
 		return sch;
 
-	qdisc_destroy(sch);
+	qdisc_put(sch);
 	return NULL;
 }
 EXPORT_SYMBOL(qdisc_create_dflt);
@@ -941,15 +941,11 @@ void qdisc_free(struct Qdisc *qdisc)
 	kfree((char *) qdisc - qdisc->padded);
 }
 
-void qdisc_destroy(struct Qdisc *qdisc)
+static void qdisc_destroy(struct Qdisc *qdisc)
 {
 	const struct Qdisc_ops  *ops = qdisc->ops;
 	struct sk_buff *skb, *tmp;
 
-	if (qdisc->flags & TCQ_F_BUILTIN ||
-	    !refcount_dec_and_test(&qdisc->refcnt))
-		return;
-
 #ifdef CONFIG_NET_SCHED
 	qdisc_hash_del(qdisc);
 
@@ -976,7 +972,16 @@ void qdisc_destroy(struct Qdisc *qdisc)
 
 	qdisc_free(qdisc);
 }
-EXPORT_SYMBOL(qdisc_destroy);
+
+void qdisc_put(struct Qdisc *qdisc)
+{
+	if (qdisc->flags & TCQ_F_BUILTIN ||
+	    !refcount_dec_and_test(&qdisc->refcnt))
+		return;
+
+	qdisc_destroy(qdisc);
+}
+EXPORT_SYMBOL(qdisc_put);
 
 /* Attach toplevel qdisc to device queue. */
 struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
@@ -1270,7 +1275,7 @@ static void shutdown_scheduler_queue(struct net_device *dev,
 		rcu_assign_pointer(dev_queue->qdisc, qdisc_default);
 		dev_queue->qdisc_sleeping = qdisc_default;
 
-		qdisc_destroy(qdisc);
+		qdisc_put(qdisc);
 	}
 }
 
@@ -1279,7 +1284,7 @@ void dev_shutdown(struct net_device *dev)
 	netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
 	if (dev_ingress_queue(dev))
 		shutdown_scheduler_queue(dev, dev_ingress_queue(dev), &noop_qdisc);
-	qdisc_destroy(dev->qdisc);
+	qdisc_put(dev->qdisc);
 	dev->qdisc = &noop_qdisc;
 
 	WARN_ON(timer_pending(&dev->watchdog_timer));

net/sched/sch_hfsc.c

@@ -1092,7 +1092,7 @@ hfsc_destroy_class(struct Qdisc *sch, struct hfsc_class *cl)
 	struct hfsc_sched *q = qdisc_priv(sch);
 
 	tcf_block_put(cl->block);
-	qdisc_destroy(cl->qdisc);
+	qdisc_put(cl->qdisc);
 	gen_kill_estimator(&cl->rate_est);
 	if (cl != &q->root)
 		kfree(cl);