net/sched: taprio: refactor one skb dequeue from TXQ to separate function

Future changes will refactor the TXQ selection procedure, and a lot of
stuff will become messy, the indentation of the bulk of the dequeue
procedure would increase, etc.

Break out the bulk of the function into a new one, which knows the TXQ
(child qdisc) we should perform a dequeue from.

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>

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 0fde303978a58cfe5fc5ce26cc8e36026406e062..272a8b7c0f9f311ef2ee57ebe6812d3ab7b2d060 100644 (file)
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -512,6 +512,66 @@ static void taprio_set_budget(struct taprio_sched *q, struct sched_entry *entry)
                             atomic64_read(&q->picos_per_byte)));
 }
 
+static struct sk_buff *taprio_dequeue_from_txq(struct Qdisc *sch, int txq,
+                                              struct sched_entry *entry,
+                                              u32 gate_mask)
+{
+       struct taprio_sched *q = qdisc_priv(sch);
+       struct net_device *dev = qdisc_dev(sch);
+       struct Qdisc *child = q->qdiscs[txq];
+       struct sk_buff *skb;
+       ktime_t guard;
+       int prio;
+       int len;
+       u8 tc;
+
+       if (unlikely(!child))
+               return NULL;
+
+       if (TXTIME_ASSIST_IS_ENABLED(q->flags)) {
+               skb = child->ops->dequeue(child);
+               if (!skb)
+                       return NULL;
+               goto skb_found;
+       }
+
+       skb = child->ops->peek(child);
+       if (!skb)
+               return NULL;
+
+       prio = skb->priority;
+       tc = netdev_get_prio_tc_map(dev, prio);
+
+       if (!(gate_mask & BIT(tc)))
+               return NULL;
+
+       len = qdisc_pkt_len(skb);
+       guard = ktime_add_ns(taprio_get_time(q), length_to_duration(q, len));
+
+       /* In the case that there's no gate entry, there's no
+        * guard band ...
+        */
+       if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
+           ktime_after(guard, entry->close_time))
+               return NULL;
+
+       /* ... and no budget. */
+       if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
+           atomic_sub_return(len, &entry->budget) < 0)
+               return NULL;
+
+       skb = child->ops->dequeue(child);
+       if (unlikely(!skb))
+               return NULL;
+
+skb_found:
+       qdisc_bstats_update(sch, skb);
+       qdisc_qstats_backlog_dec(sch, skb);
+       sch->q.qlen--;
+
+       return skb;
+}
+
 /* Will not be called in the full offload case, since the TX queues are
  * attached to the Qdisc created using qdisc_create_dflt()
  */
@@ -537,64 +597,9 @@ static struct sk_buff *taprio_dequeue(struct Qdisc *sch)
                goto done;
 
        for (i = 0; i < dev->num_tx_queues; i++) {
-               struct Qdisc *child = q->qdiscs[i];
-               ktime_t guard;
-               int prio;
-               int len;
-               u8 tc;
-
-               if (unlikely(!child))
-                       continue;
-
-               if (TXTIME_ASSIST_IS_ENABLED(q->flags)) {
-                       skb = child->ops->dequeue(child);
-                       if (!skb)
-                               continue;
-                       goto skb_found;
-               }
-
-               skb = child->ops->peek(child);
-               if (!skb)
-                       continue;
-
-               prio = skb->priority;
-               tc = netdev_get_prio_tc_map(dev, prio);
-
-               if (!(gate_mask & BIT(tc))) {
-                       skb = NULL;
-                       continue;
-               }
-
-               len = qdisc_pkt_len(skb);
-               guard = ktime_add_ns(taprio_get_time(q),
-                                    length_to_duration(q, len));
-
-               /* In the case that there's no gate entry, there's no
-                * guard band ...
-                */
-               if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
-                   ktime_after(guard, entry->close_time)) {
-                       skb = NULL;
-                       continue;
-               }
-
-               /* ... and no budget. */
-               if (gate_mask != TAPRIO_ALL_GATES_OPEN &&
-                   atomic_sub_return(len, &entry->budget) < 0) {
-                       skb = NULL;
-                       continue;
-               }
-
-               skb = child->ops->dequeue(child);
-               if (unlikely(!skb))
-                       continue;
-
-skb_found:
-               qdisc_bstats_update(sch, skb);
-               qdisc_qstats_backlog_dec(sch, skb);
-               sch->q.qlen--;
-
-               goto done;
+               skb = taprio_dequeue_from_txq(sch, i, entry, gate_mask);
+               if (skb)
+                       goto done;
        }
 
 done: