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net/sched: taprio: delete peek() implementation

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There isn't any code in the network stack which calls taprio_peek().
We only see qdisc->ops->peek() being called on child qdiscs of other
classful qdiscs, never from the generic qdisc code. Whereas taprio is
never a child qdisc, it is always root.

This snippet of a comment from qdisc_peek_dequeued() seems to confirm:

	/* we can reuse ->gso_skb because peek isn't called for root qdiscs */

Since I've been known to be wrong many times though, I'm not completely
removing it, but leaving a stub function in place which emits a warning.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2023-02-07 15:54:26 +02:00 committed by David S. Miller
parent 6da13bf976
commit ecc0cc9863
1 changed files with 1 additions and 42 deletions
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43
net/sched/sch_taprio.c
View file

@ -499,50 +499,9 @@ static int taprio_enqueue(struct sk_buff *skb, struct Qdisc *sch,
return taprio_enqueue_one(skb, sch, child, to_free);
}
/* Will not be called in the full offload case, since the TX queues are
* attached to the Qdisc created using qdisc_create_dflt()
*/
static struct sk_buff *taprio_peek(struct Qdisc *sch)
{
struct taprio_sched *q = qdisc_priv(sch);
struct net_device *dev = qdisc_dev(sch);
struct sched_entry *entry;
struct sk_buff *skb;
u32 gate_mask;
int i;
rcu_read_lock();
entry = rcu_dereference(q->current_entry);
gate_mask = entry ? entry->gate_mask : TAPRIO_ALL_GATES_OPEN;
rcu_read_unlock();
if (!gate_mask)
return NULL;
for (i = 0; i < dev->num_tx_queues; i++) {
struct Qdisc *child = q->qdiscs[i];
int prio;
u8 tc;
if (unlikely(!child))
continue;
skb = child->ops->peek(child);
if (!skb)
continue;
if (TXTIME_ASSIST_IS_ENABLED(q->flags))
return skb;
prio = skb->priority;
tc = netdev_get_prio_tc_map(dev, prio);
if (!(gate_mask & BIT(tc)))
continue;
return skb;
}
WARN_ONCE(1, "taprio only supports operating as root qdisc, peek() not implemented");
return NULL;
}