[Cake] [PATCH net-next v6 2/4] net/sched: cake: use a dedicated split-GSO list iterator

[Jamal Hadi Salim <jhs@mojatatu.com>]

skb_list_walk_safe(segs, segs, nskb) reuses the list head as the walk
cursor, so segs no longer names the segment list once the walk finishes.
Use a separate seg cursor to keep the head and the walker distinct. No
behaviour change.

Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>

---
v5 -> v6: split out of the single v5 patch; no code change.
---
 net/sched/sch_cake.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index 6432d10c992e..0d13c4b0bfe3 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1810,7 +1810,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		WRITE_ONCE(b->max_skblen, len);
 
 	if (qdisc_pkt_segs(skb) > 1 && q->config->rate_flags & CAKE_FLAG_SPLIT_GSO) {
-		struct sk_buff *segs, *nskb;
+		struct sk_buff *segs, *nskb, *seg;
 		netdev_features_t features = netif_skb_features(skb);
 		unsigned int slen = 0, numsegs = 0;
 
@@ -1818,19 +1818,19 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		if (IS_ERR_OR_NULL(segs))
 			return qdisc_drop(skb, sch, to_free);
 
-		skb_list_walk_safe(segs, segs, nskb) {
-			skb_mark_not_on_list(segs);
-			qdisc_skb_cb(segs)->pkt_len = segs->len;
-			qdisc_skb_cb(segs)->pkt_segs = 1;
-			cobalt_set_enqueue_time(segs, now);
-			get_cobalt_cb(segs)->adjusted_len = cake_overhead(q,
-									  segs);
-			flow_queue_add(flow, segs);
+		skb_list_walk_safe(segs, seg, nskb) {
+			skb_mark_not_on_list(seg);
+			qdisc_skb_cb(seg)->pkt_len = seg->len;
+			qdisc_skb_cb(seg)->pkt_segs = 1;
+			cobalt_set_enqueue_time(seg, now);
+			get_cobalt_cb(seg)->adjusted_len = cake_overhead(q,
+									 seg);
+			flow_queue_add(flow, seg);
 
 			qdisc_qlen_inc(sch);
 			numsegs++;
-			slen += segs->len;
-			q->buffer_used += segs->truesize;
+			q->buffer_used += seg->truesize;
+			slen += seg->len;
 			WRITE_ONCE(b->packets, b->packets + 1);
 		}
 
-- 
2.43.0