write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/net/sched/sch_netem.c
..
..
@@ -773,12 +773,10 @@
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  * signed 16 bit values.
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  */
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-static int get_dist_table(struct Qdisc *sch, struct disttable **tbl,
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-			  const struct nlattr *attr)
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+static int get_dist_table(struct disttable **tbl, const struct nlattr *attr)
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 {
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 	size_t n = nla_len(attr)/sizeof(__s16);
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 	const __s16 *data = nla_data(attr);
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-	spinlock_t *root_lock;
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 	struct disttable *d;
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 	int i;
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..
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@@ -793,13 +791,7 @@
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 	for (i = 0; i < n; i++)
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 		d->table[i] = data[i];
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-	root_lock = qdisc_root_sleeping_lock(sch);
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-
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-	spin_lock_bh(root_lock);
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-	swap(*tbl, d);
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-	spin_unlock_bh(root_lock);
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-
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-	dist_free(d);
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+	*tbl = d;
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 	return 0;
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 }
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..
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@@ -956,6 +948,8 @@
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 {
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 	struct netem_sched_data *q = qdisc_priv(sch);
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 	struct nlattr *tb[TCA_NETEM_MAX + 1];
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+	struct disttable *delay_dist = NULL;
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+	struct disttable *slot_dist = NULL;
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 	struct tc_netem_qopt *qopt;
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 	struct clgstate old_clg;
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 	int old_loss_model = CLG_RANDOM;
..
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@@ -969,6 +963,19 @@
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 	if (ret < 0)
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 		return ret;
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+	if (tb[TCA_NETEM_DELAY_DIST]) {
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+		ret = get_dist_table(&delay_dist, tb[TCA_NETEM_DELAY_DIST]);
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+		if (ret)
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+			goto table_free;
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+	}
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+
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+	if (tb[TCA_NETEM_SLOT_DIST]) {
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+		ret = get_dist_table(&slot_dist, tb[TCA_NETEM_SLOT_DIST]);
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+		if (ret)
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+			goto table_free;
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+	}
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+
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+	sch_tree_lock(sch);
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 	/* backup q->clg and q->loss_model */
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 	old_clg = q->clg;
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 	old_loss_model = q->loss_model;
..
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@@ -977,26 +984,17 @@
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 		ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
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 		if (ret) {
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 			q->loss_model = old_loss_model;
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-			return ret;
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+			q->clg = old_clg;
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+			goto unlock;
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 		}
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 	} else {
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 		q->loss_model = CLG_RANDOM;
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 	}
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-	if (tb[TCA_NETEM_DELAY_DIST]) {
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-		ret = get_dist_table(sch, &q->delay_dist,
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-				     tb[TCA_NETEM_DELAY_DIST]);
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-		if (ret)
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-			goto get_table_failure;
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-	}
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-
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-	if (tb[TCA_NETEM_SLOT_DIST]) {
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-		ret = get_dist_table(sch, &q->slot_dist,
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-				     tb[TCA_NETEM_SLOT_DIST]);
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-		if (ret)
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-			goto get_table_failure;
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-	}
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-
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+	if (delay_dist)
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+		swap(q->delay_dist, delay_dist);
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+	if (slot_dist)
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+		swap(q->slot_dist, slot_dist);
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 	sch->limit = qopt->limit;
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 	q->latency = PSCHED_TICKS2NS(qopt->latency);
..
..
@@ -1044,15 +1042,12 @@
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 	/* capping jitter to the range acceptable by tabledist() */
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 	q->jitter = min_t(s64, abs(q->jitter), INT_MAX);
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-	return ret;
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+unlock:
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+	sch_tree_unlock(sch);
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-get_table_failure:
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-	/* recover clg and loss_model, in case of
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-	 * q->clg and q->loss_model were modified
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-	 * in get_loss_clg()
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-	 */
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-	q->clg = old_clg;
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-	q->loss_model = old_loss_model;
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+table_free:
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+	dist_free(delay_dist);
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+	dist_free(slot_dist);
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 	return ret;
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 }
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