1 files changed, 117 insertions, 0 deletions
diff --git a/net/sched/sch_mqprio_lib.c b/net/sched/sch_mqprio_lib.c
new file mode 100644
index 000000000000..c58a533b8ec5
--- /dev/null
+++ b/net/sched/sch_mqprio_lib.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/netlink.h>
+#include <linux/types.h>
+#include <net/pkt_sched.h>
+
+#include "sch_mqprio_lib.h"
+
+/* Returns true if the intervals [a, b) and [c, d) overlap. */
+static bool intervals_overlap(int a, int b, int c, int d)
+{
+	int left = max(a, c), right = min(b, d);
+
+	return left < right;
+}
+
+static int mqprio_validate_queue_counts(struct net_device *dev,
+					const struct tc_mqprio_qopt *qopt,
+					bool allow_overlapping_txqs,
+					struct netlink_ext_ack *extack)
+{
+	int i, j;
+
+	for (i = 0; i < qopt->num_tc; i++) {
+		unsigned int last = qopt->offset[i] + qopt->count[i];
+
+		if (!qopt->count[i]) {
+			NL_SET_ERR_MSG_FMT_MOD(extack, "No queues for TC %d",
+					       i);
+			return -EINVAL;
+		}
+
+		/* Verify the queue count is in tx range being equal to the
+		 * real_num_tx_queues indicates the last queue is in use.
+		 */
+		if (qopt->offset[i] >= dev->real_num_tx_queues ||
+		    last > dev->real_num_tx_queues) {
+			NL_SET_ERR_MSG_FMT_MOD(extack,
+					       "Queues %d:%d for TC %d exceed the %d TX queues available",
+					       qopt->count[i], qopt->offset[i],
+					       i, dev->real_num_tx_queues);
+			return -EINVAL;
+		}
+
+		if (allow_overlapping_txqs)
+			continue;
+
+		/* Verify that the offset and counts do not overlap */
+		for (j = i + 1; j < qopt->num_tc; j++) {
+			if (intervals_overlap(qopt->offset[i], last,
+					      qopt->offset[j],
+					      qopt->offset[j] +
+					      qopt->count[j])) {
+				NL_SET_ERR_MSG_FMT_MOD(extack,
+						       "TC %d queues %d@%d overlap with TC %d queues %d@%d",
+						       i, qopt->count[i], qopt->offset[i],
+						       j, qopt->count[j], qopt->offset[j]);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+int mqprio_validate_qopt(struct net_device *dev, struct tc_mqprio_qopt *qopt,
+			 bool validate_queue_counts,
+			 bool allow_overlapping_txqs,
+			 struct netlink_ext_ack *extack)
+{
+	int i, err;
+
+	/* Verify num_tc is not out of max range */
+	if (qopt->num_tc > TC_MAX_QUEUE) {
+		NL_SET_ERR_MSG(extack,
+			       "Number of traffic classes is outside valid range");
+		return -EINVAL;
+	}
+
+	/* Verify priority mapping uses valid tcs */
+	for (i = 0; i <= TC_BITMASK; i++) {
+		if (qopt->prio_tc_map[i] >= qopt->num_tc) {
+			NL_SET_ERR_MSG(extack,
+				       "Invalid traffic class in priority to traffic class mapping");
+			return -EINVAL;
+		}
+	}
+
+	if (validate_queue_counts) {
+		err = mqprio_validate_queue_counts(dev, qopt,
+						   allow_overlapping_txqs,
+						   extack);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mqprio_validate_qopt);
+
+void mqprio_qopt_reconstruct(struct net_device *dev, struct tc_mqprio_qopt *qopt)
+{
+	int tc, num_tc = netdev_get_num_tc(dev);
+
+	qopt->num_tc = num_tc;
+	memcpy(qopt->prio_tc_map, dev->prio_tc_map, sizeof(qopt->prio_tc_map));
+
+	for (tc = 0; tc < num_tc; tc++) {
+		qopt->count[tc] = dev->tc_to_txq[tc].count;
+		qopt->offset[tc] = dev->tc_to_txq[tc].offset;
+	}
+}
+EXPORT_SYMBOL_GPL(mqprio_qopt_reconstruct);
+
+MODULE_LICENSE("GPL");