linux-kernel - [PATCH v3 net 3/4] net/sched: taprio: fix impacted fields value during cycle time adjustment

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Message-Id: <20231219081453.718489-4-faizal.abdul.rahim@linux.intel.com>
Date: Tue, 19 Dec 2023 03:14:52 -0500
From: Faizal Rahim <faizal.abdul.rahim@...ux.intel.com>
To: Vladimir Oltean <vladimir.oltean@....com>,
	Vinicius Costa Gomes <vinicius.gomes@...el.com>,
	Jamal Hadi Salim <jhs@...atatu.com>,
	Cong Wang <xiyou.wangcong@...il.com>,
	Jiri Pirko <jiri@...nulli.us>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v3 net 3/4] net/sched: taprio: fix impacted fields value during cycle time adjustment

During the cycle time adjustment period, there's a single entry left
from the oper schedule to be executed. As a result, updates are
needed for the affected fields' logic, which did not previously
consider dynamic scheduling.

Fixes: a306a90c8ffe ("net/sched: taprio: calculate tc gate durations")
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@...ux.intel.com>
---
 net/sched/sch_taprio.c | 44 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index e70dc69c311f..a3c71be21af2 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -285,7 +285,8 @@ static void taprio_update_queue_max_sdu(struct taprio_sched *q,
 		/* TC gate never closes => keep the queueMaxSDU
 		 * selected by the user
 		 */
-		if (sched->max_open_gate_duration[tc] == sched->cycle_time) {
+		if (sched->max_open_gate_duration[tc] == sched->cycle_time &&
+		    !sched_switch_pending(sched)) {
 			max_sdu_dynamic = U32_MAX;
 		} else {
 			u32 max_frm_len;
@@ -681,7 +682,8 @@ static void taprio_set_budgets(struct taprio_sched *q,
 
 	for (tc = 0; tc < num_tc; tc++) {
 		/* Traffic classes which never close have infinite budget */
-		if (entry->gate_duration[tc] == sched->cycle_time)
+		if (entry->gate_duration[tc] == sched->cycle_time &&
+		    !sched_switch_pending(sched))
 			budget = INT_MAX;
 		else
 			budget = div64_u64((u64)entry->gate_duration[tc] * PSEC_PER_NSEC,
@@ -893,6 +895,29 @@ static bool should_restart_cycle(const struct sched_gate_list *oper,
 	return false;
 }
 
+/* Open gate duration were calculated at the beginning with consideration of
+ * multiple entries. If sched_switch_pending() is active, there's only a single
+ * remaining entry left from oper to run. Update open gate duration based
+ * on this last entry.
+ */
+static void update_open_gate_duration(struct sched_entry *entry,
+				      struct sched_gate_list *oper,
+				      int num_tc,
+				      u64 open_gate_duration)
+{
+	int tc;
+
+	for (tc = 0; tc < num_tc; tc++) {
+		if (entry->gate_mask & BIT(tc)) {
+			entry->gate_duration[tc] = open_gate_duration;
+			oper->max_open_gate_duration[tc] = open_gate_duration;
+		} else {
+			entry->gate_duration[tc] = 0;
+			oper->max_open_gate_duration[tc] = 0;
+		}
+	}
+}
+
 static bool should_extend_cycle(const struct sched_gate_list *oper,
 				ktime_t new_base_time,
 				ktime_t next_entry_end_time,
@@ -1002,13 +1027,26 @@ static enum hrtimer_restart advance_sched(struct hrtimer *timer)
 			/* The next entry is the last entry we will run from
 			 * oper, subsequent ones will take from the new admin
 			 */
+			u64 new_gate_duration =
+				next->interval + oper->cycle_time_correction;
+			struct qdisc_size_table *stab;
+
 			oper->cycle_end_time = new_base_time;
 			end_time = new_base_time;
+
+			update_open_gate_duration(next, oper, num_tc,
+						  new_gate_duration);
+			rcu_read_lock();
+			stab = rcu_dereference(q->root->stab);
+			taprio_update_queue_max_sdu(q, oper, stab);
+			rcu_read_unlock();
 		}
 	}
 
 	for (tc = 0; tc < num_tc; tc++) {
-		if (next->gate_duration[tc] == oper->cycle_time)
+		if (sched_switch_pending(oper) && (next->gate_mask & BIT(tc)))
+			next->gate_close_time[tc] = end_time;
+		else if (next->gate_duration[tc] == oper->cycle_time)
 			next->gate_close_time[tc] = KTIME_MAX;
 		else
 			next->gate_close_time[tc] = ktime_add_ns(entry->end_time,
-- 
2.25.1