Merge branch 'fixes-for-tc-taprio-software-mode'

Vladimir Oltean says:

====================
Fixes for tc-taprio software mode

While working on some new features for tc-taprio, I found some strange
behavior which looked like bugs. I was able to eventually trigger a NULL
pointer dereference. This patch set fixes 2 issues I saw. Detailed
explanation in patches.
====================

Link: https://lore.kernel.org/r/20220915100802.2308279-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/sched/sch_taprio.c

@@ -67,6 +67,7 @@ struct taprio_sched {
 	u32 flags;
 	enum tk_offsets tk_offset;
 	int clockid;
+	bool offloaded;
 	atomic64_t picos_per_byte; /* Using picoseconds because for 10Gbps+
 				    * speeds it's sub-nanoseconds per byte
 				    */
@@ -1279,6 +1280,8 @@ static int taprio_enable_offload(struct net_device *dev,
 		goto done;
 	}
 
+	q->offloaded = true;
+
 done:
 	taprio_offload_free(offload);
 
@@ -1293,12 +1296,9 @@ static int taprio_disable_offload(struct net_device *dev,
 	struct tc_taprio_qopt_offload *offload;
 	int err;
 
-	if (!FULL_OFFLOAD_IS_ENABLED(q->flags))
+	if (!q->offloaded)
 		return 0;
 
-	if (!ops->ndo_setup_tc)
-		return -EOPNOTSUPP;
-
 	offload = taprio_offload_alloc(0);
 	if (!offload) {
 		NL_SET_ERR_MSG(extack,
@@ -1314,6 +1314,8 @@ static int taprio_disable_offload(struct net_device *dev,
 		goto out;
 	}
 
+	q->offloaded = false;
+
 out:
 	taprio_offload_free(offload);
 
@@ -1949,12 +1951,14 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 
 static struct Qdisc *taprio_leaf(struct Qdisc *sch, unsigned long cl)
 {
-	struct netdev_queue *dev_queue = taprio_queue_get(sch, cl);
+	struct taprio_sched *q = qdisc_priv(sch);
+	struct net_device *dev = qdisc_dev(sch);
+	unsigned int ntx = cl - 1;
 
-	if (!dev_queue)
+	if (ntx >= dev->num_tx_queues)
 		return NULL;
 
-	return dev_queue->qdisc_sleeping;
+	return q->qdiscs[ntx];
 }
 
 static unsigned long taprio_find(struct Qdisc *sch, u32 classid)