Merge branch 'net-sched-taprio-fix-picos_per_byte-miscalculation'

Leandro Dorileo says:

====================
net/sched: taprio: fix picos_per_byte miscalculation

This set fixes miscalculations based on invalid link speed values.

Changes in v6:
 + Avoid locking a spinlock while calling __ethtool_get_link_ksettings()
   (suggested by: Cong Wang);

Changes in v5:
 + Don't iterate over all the net_device maintained list (suggested by: Florian Fainelli);

Changes in v4:
 + converted pr_info calls to netdev_dbg (suggested by: Florian Fainelli);

Changes in v3:
 + yet pr_info() format warnings;

Changes in v2:
 + fixed pr_info() format both on cbs and taprio patches;
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_cbs.c

@@ -61,16 +61,20 @@
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/skbuff.h>
+#include <net/netevent.h>
 #include <net/netlink.h>
 #include <net/sch_generic.h>
 #include <net/pkt_sched.h>
 
+static LIST_HEAD(cbs_list);
+static DEFINE_SPINLOCK(cbs_list_lock);
+
 #define BYTES_PER_KBIT (1000LL / 8)
 
 struct cbs_sched_data {
 	bool offload;
 	int queue;
-	s64 port_rate; /* in bytes/s */
+	atomic64_t port_rate; /* in bytes/s */
 	s64 last; /* timestamp in ns */
 	s64 credits; /* in bytes */
 	s32 locredit; /* in bytes */
@@ -82,6 +86,7 @@ struct cbs_sched_data {
 		       struct sk_buff **to_free);
 	struct sk_buff *(*dequeue)(struct Qdisc *sch);
 	struct Qdisc *qdisc;
+	struct list_head cbs_list;
 };
 
 static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch,
@@ -181,6 +186,11 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
 	s64 credits;
 	int len;
 
+	if (atomic64_read(&q->port_rate) == -1) {
+		WARN_ONCE(1, "cbs: dequeue() called with unknown port rate.");
+		return NULL;
+	}
+
 	if (q->credits < 0) {
 		credits = timediff_to_credits(now - q->last, q->idleslope);
 
@@ -207,7 +217,8 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
 	/* As sendslope is a negative number, this will decrease the
 	 * amount of q->credits.
 	 */
-	credits = credits_from_len(len, q->sendslope, q->port_rate);
+	credits = credits_from_len(len, q->sendslope,
+				   atomic64_read(&q->port_rate));
 	credits += q->credits;
 
 	q->credits = max_t(s64, credits, q->locredit);
@@ -294,6 +305,50 @@ static int cbs_enable_offload(struct net_device *dev, struct cbs_sched_data *q,
 	return 0;
 }
 
+static void cbs_set_port_rate(struct net_device *dev, struct cbs_sched_data *q)
+{
+	struct ethtool_link_ksettings ecmd;
+	int port_rate = -1;
+
+	if (!__ethtool_get_link_ksettings(dev, &ecmd) &&
+	    ecmd.base.speed != SPEED_UNKNOWN)
+		port_rate = ecmd.base.speed * 1000 * BYTES_PER_KBIT;
+
+	atomic64_set(&q->port_rate, port_rate);
+	netdev_dbg(dev, "cbs: set %s's port_rate to: %lld, linkspeed: %d\n",
+		   dev->name, (long long)atomic64_read(&q->port_rate),
+		   ecmd.base.speed);
+}
+
+static int cbs_dev_notifier(struct notifier_block *nb, unsigned long event,
+			    void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct cbs_sched_data *q;
+	struct net_device *qdev;
+	bool found = false;
+
+	ASSERT_RTNL();
+
+	if (event != NETDEV_UP && event != NETDEV_CHANGE)
+		return NOTIFY_DONE;
+
+	spin_lock(&cbs_list_lock);
+	list_for_each_entry(q, &cbs_list, cbs_list) {
+		qdev = qdisc_dev(q->qdisc);
+		if (qdev == dev) {
+			found = true;
+			break;
+		}
+	}
+	spin_unlock(&cbs_list_lock);
+
+	if (found)
+		cbs_set_port_rate(dev, q);
+
+	return NOTIFY_DONE;
+}
+
 static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
 		      struct netlink_ext_ack *extack)
 {
@@ -315,16 +370,7 @@ static int cbs_change(struct Qdisc *sch, struct nlattr *opt,
 	qopt = nla_data(tb[TCA_CBS_PARMS]);
 
 	if (!qopt->offload) {
-		struct ethtool_link_ksettings ecmd;
-		s64 link_speed;
-
-		if (!__ethtool_get_link_ksettings(dev, &ecmd))
-			link_speed = ecmd.base.speed;
-		else
-			link_speed = SPEED_1000;
-
-		q->port_rate = link_speed * 1000 * BYTES_PER_KBIT;
-
+		cbs_set_port_rate(dev, q);
 		cbs_disable_offload(dev, q);
 	} else {
 		err = cbs_enable_offload(dev, q, qopt, extack);
@@ -347,6 +393,7 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
 {
 	struct cbs_sched_data *q = qdisc_priv(sch);
 	struct net_device *dev = qdisc_dev(sch);
+	int err;
 
 	if (!opt) {
 		NL_SET_ERR_MSG(extack, "Missing CBS qdisc options  which are mandatory");
@@ -367,7 +414,17 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
 
 	qdisc_watchdog_init(&q->watchdog, sch);
 
-	return cbs_change(sch, opt, extack);
+	err = cbs_change(sch, opt, extack);
+	if (err)
+		return err;
+
+	if (!q->offload) {
+		spin_lock(&cbs_list_lock);
+		list_add(&q->cbs_list, &cbs_list);
+		spin_unlock(&cbs_list_lock);
+	}
+
+	return 0;
 }
 
 static void cbs_destroy(struct Qdisc *sch)
@@ -375,8 +432,11 @@ static void cbs_destroy(struct Qdisc *sch)
 	struct cbs_sched_data *q = qdisc_priv(sch);
 	struct net_device *dev = qdisc_dev(sch);
 
-	qdisc_watchdog_cancel(&q->watchdog);
+	spin_lock(&cbs_list_lock);
+	list_del(&q->cbs_list);
+	spin_unlock(&cbs_list_lock);
 
+	qdisc_watchdog_cancel(&q->watchdog);
 	cbs_disable_offload(dev, q);
 
 	if (q->qdisc)
@@ -487,14 +547,24 @@ static struct Qdisc_ops cbs_qdisc_ops __read_mostly = {
 	.owner		=	THIS_MODULE,
 };
 
+static struct notifier_block cbs_device_notifier = {
+	.notifier_call = cbs_dev_notifier,
+};
+
 static int __init cbs_module_init(void)
 {
+	int err = register_netdevice_notifier(&cbs_device_notifier);
+
+	if (err)
+		return err;
+
 	return register_qdisc(&cbs_qdisc_ops);
 }
 
 static void __exit cbs_module_exit(void)
 {
 	unregister_qdisc(&cbs_qdisc_ops);
+	unregister_netdevice_notifier(&cbs_device_notifier);
 }
 module_init(cbs_module_init)
 module_exit(cbs_module_exit)

net/sched/sch_taprio.c

@@ -20,6 +20,9 @@
 #include <net/pkt_cls.h>
 #include <net/sch_generic.h>
 
+static LIST_HEAD(taprio_list);
+static DEFINE_SPINLOCK(taprio_list_lock);
+
 #define TAPRIO_ALL_GATES_OPEN -1
 
 struct sched_entry {
@@ -42,9 +45,9 @@ struct taprio_sched {
 	struct Qdisc *root;
 	s64 base_time;
 	int clockid;
-	int picos_per_byte; /* Using picoseconds because for 10Gbps+
-			     * speeds it's sub-nanoseconds per byte
-			     */
+	atomic64_t picos_per_byte; /* Using picoseconds because for 10Gbps+
+				    * speeds it's sub-nanoseconds per byte
+				    */
 	size_t num_entries;
 
 	/* Protects the update side of the RCU protected current_entry */
@@ -53,6 +56,7 @@ struct taprio_sched {
 	struct list_head entries;
 	ktime_t (*get_time)(void);
 	struct hrtimer advance_timer;
+	struct list_head taprio_list;
 };
 
 static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
@@ -117,7 +121,7 @@ static struct sk_buff *taprio_peek(struct Qdisc *sch)
 
 static inline int length_to_duration(struct taprio_sched *q, int len)
 {
-	return (len * q->picos_per_byte) / 1000;
+	return (len * atomic64_read(&q->picos_per_byte)) / 1000;
 }
 
 static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
@@ -129,6 +133,11 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
 	u32 gate_mask;
 	int i;
 
+	if (atomic64_read(&q->picos_per_byte) == -1) {
+		WARN_ONCE(1, "taprio: dequeue() called with unknown picos per byte.");
+		return NULL;
+	}
+
 	rcu_read_lock();
 	entry = rcu_dereference(q->current_entry);
 	/* if there's no entry, it means that the schedule didn't
@@ -233,7 +242,7 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer)
 
 	next->close_time = close_time;
 	atomic_set(&next->budget,
-		   (next->interval * 1000) / q->picos_per_byte);
+		   (next->interval * 1000) / atomic64_read(&q->picos_per_byte));
 
 first_run:
 	rcu_assign_pointer(q->current_entry, next);
@@ -567,7 +576,8 @@ static void taprio_start_sched(struct Qdisc *sch, ktime_t start)
 
 	first->close_time = ktime_add_ns(start, first->interval);
 	atomic_set(&first->budget,
-		   (first->interval * 1000) / q->picos_per_byte);
+		   (first->interval * 1000) /
+		   atomic64_read(&q->picos_per_byte));
 	rcu_assign_pointer(q->current_entry, NULL);
 
 	spin_unlock_irqrestore(&q->current_entry_lock, flags);
@@ -575,6 +585,52 @@ static void taprio_start_sched(struct Qdisc *sch, ktime_t start)
 	hrtimer_start(&q->advance_timer, start, HRTIMER_MODE_ABS);
 }
 
+static void taprio_set_picos_per_byte(struct net_device *dev,
+				      struct taprio_sched *q)
+{
+	struct ethtool_link_ksettings ecmd;
+	int picos_per_byte = -1;
+
+	if (!__ethtool_get_link_ksettings(dev, &ecmd) &&
+	    ecmd.base.speed != SPEED_UNKNOWN)
+		picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
+					   ecmd.base.speed * 1000 * 1000);
+
+	atomic64_set(&q->picos_per_byte, picos_per_byte);
+	netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed: %d\n",
+		   dev->name, (long long)atomic64_read(&q->picos_per_byte),
+		   ecmd.base.speed);
+}
+
+static int taprio_dev_notifier(struct notifier_block *nb, unsigned long event,
+			       void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct net_device *qdev;
+	struct taprio_sched *q;
+	bool found = false;
+
+	ASSERT_RTNL();
+
+	if (event != NETDEV_UP && event != NETDEV_CHANGE)
+		return NOTIFY_DONE;
+
+	spin_lock(&taprio_list_lock);
+	list_for_each_entry(q, &taprio_list, taprio_list) {
+		qdev = qdisc_dev(q->root);
+		if (qdev == dev) {
+			found = true;
+			break;
+		}
+	}
+	spin_unlock(&taprio_list_lock);
+
+	if (found)
+		taprio_set_picos_per_byte(dev, q);
+
+	return NOTIFY_DONE;
+}
+
 static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 			 struct netlink_ext_ack *extack)
 {
@@ -582,9 +638,7 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 	struct taprio_sched *q = qdisc_priv(sch);
 	struct net_device *dev = qdisc_dev(sch);
 	struct tc_mqprio_qopt *mqprio = NULL;
-	struct ethtool_link_ksettings ecmd;
 	int i, err, size;
-	s64 link_speed;
 	ktime_t start;
 
 	err = nla_parse_nested(tb, TCA_TAPRIO_ATTR_MAX, opt,
@@ -657,14 +711,7 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 					       mqprio->prio_tc_map[i]);
 	}
 
-	if (!__ethtool_get_link_ksettings(dev, &ecmd))
-		link_speed = ecmd.base.speed;
-	else
-		link_speed = SPEED_1000;
-
-	q->picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
-				      link_speed * 1000 * 1000);
-
+	taprio_set_picos_per_byte(dev, q);
 	start = taprio_get_start_time(sch);
 	if (!start)
 		return 0;
@@ -681,6 +728,10 @@ static void taprio_destroy(struct Qdisc *sch)
 	struct sched_entry *entry, *n;
 	unsigned int i;
 
+	spin_lock(&taprio_list_lock);
+	list_del(&q->taprio_list);
+	spin_unlock(&taprio_list_lock);
+
 	hrtimer_cancel(&q->advance_timer);
 
 	if (q->qdiscs) {
@@ -735,6 +786,10 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
 	if (!opt)
 		return -EINVAL;
 
+	spin_lock(&taprio_list_lock);
+	list_add(&q->taprio_list, &taprio_list);
+	spin_unlock(&taprio_list_lock);
+
 	return taprio_change(sch, opt, extack);
 }
 
@@ -947,14 +1002,24 @@ static struct Qdisc_ops taprio_qdisc_ops __read_mostly = {
 	.owner		= THIS_MODULE,
 };
 
+static struct notifier_block taprio_device_notifier = {
+	.notifier_call = taprio_dev_notifier,
+};
+
 static int __init taprio_module_init(void)
 {
+	int err = register_netdevice_notifier(&taprio_device_notifier);
+
+	if (err)
+		return err;
+
 	return register_qdisc(&taprio_qdisc_ops);
 }
 
 static void __exit taprio_module_exit(void)
 {
 	unregister_qdisc(&taprio_qdisc_ops);
+	unregister_netdevice_notifier(&taprio_device_notifier);
 }
 
 module_init(taprio_module_init);