net/mlx4_en: Force user priority by QP attribute

Instead of relying on HW to change schedule queue by UP, schedule
queue is fixed for a tx_ring, and UP in WQE is ignored in this aspect. This
resolves two issues with untagged traffic:
1. untagged traffic has no UP in packet which is needed for QoS. The change
above allows setting the schedule queue (and by that the UP) of such a stream.
2. BlueFlame uses the same field used by vlan tag. So forcing UP from QPC
allows using BF for untagged but prioritized traffic.

In old firmware that force UP is not supported, untagged traffic will not subject to
QoS.

Because UP is set by QP, need to always have a tx ring per UP, even if pfcrx
module paramter is false.

Signed-off-by: Amir Vadai <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/mellanox/mlx4/en_main.c

···
 		params->prof[i].tx_ring_size = MLX4_EN_DEF_TX_RING_SIZE;
 		params->prof[i].rx_ring_size = MLX4_EN_DEF_RX_RING_SIZE;
 		params->prof[i].tx_ring_num = MLX4_EN_NUM_TX_RINGS +
-			(!!pfcrx) * MLX4_EN_NUM_PPP_RINGS;
+			MLX4_EN_NUM_PPP_RINGS;
 		params->prof[i].rss_rings = 0;
 	}
 

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

···
 
 		/* Configure ring */
 		tx_ring = &priv->tx_ring[i];
-		err = mlx4_en_activate_tx_ring(priv, tx_ring, cq->mcq.cqn);
+		err = mlx4_en_activate_tx_ring(priv, tx_ring, cq->mcq.cqn,
+				max(0, i - MLX4_EN_NUM_TX_RINGS));
 		if (err) {
 			en_err(priv, "Failed allocating Tx ring\n");
 			mlx4_en_deactivate_cq(priv, cq);

drivers/net/ethernet/mellanox/mlx4/en_resources.c

···
 
 void mlx4_en_fill_qp_context(struct mlx4_en_priv *priv, int size, int stride,
 			     int is_tx, int rss, int qpn, int cqn,
-			     struct mlx4_qp_context *context)
+			     int user_prio, struct mlx4_qp_context *context)
 {
 	struct mlx4_en_dev *mdev = priv->mdev;
 
···
 	context->local_qpn = cpu_to_be32(qpn);
 	context->pri_path.ackto = 1 & 0x07;
 	context->pri_path.sched_queue = 0x83 | (priv->port - 1) << 6;
+	if (user_prio >= 0) {
+		context->pri_path.sched_queue |= user_prio << 3;
+		context->pri_path.feup = 1 << 6;
+	}
 	context->pri_path.counter_index = 0xff;
 	context->cqn_send = cpu_to_be32(cqn);
 	context->cqn_recv = cpu_to_be32(cqn);

drivers/net/ethernet/mellanox/mlx4/en_rx.c

···
 
 	memset(context, 0, sizeof *context);
 	mlx4_en_fill_qp_context(priv, ring->actual_size, ring->stride, 0, 0,
-				qpn, ring->cqn, context);
+				qpn, ring->cqn, -1, context);
 	context->db_rec_addr = cpu_to_be64(ring->wqres.db.dma);
 
 	/* Cancel FCS removal if FW allows */
···
 	}
 	rss_map->indir_qp.event = mlx4_en_sqp_event;
 	mlx4_en_fill_qp_context(priv, 0, 0, 0, 1, priv->base_qpn,
-				priv->rx_ring[0].cqn, &context);
+				priv->rx_ring[0].cqn, -1, &context);
 
 	if (!priv->prof->rss_rings || priv->prof->rss_rings > priv->rx_ring_num)
 		rss_rings = priv->rx_ring_num;

drivers/net/ethernet/mellanox/mlx4/en_tx.c

···
 
 int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
 			     struct mlx4_en_tx_ring *ring,
-			     int cq)
+			     int cq, int user_prio)
 {
 	struct mlx4_en_dev *mdev = priv->mdev;
 	int err;
···
 	ring->doorbell_qpn = ring->qp.qpn << 8;
 
 	mlx4_en_fill_qp_context(priv, ring->size, ring->stride, 1, 0, ring->qpn,
-				ring->cqn, &ring->context);
+				ring->cqn, user_prio, &ring->context);
 	if (ring->bf_enabled)
 		ring->context.usr_page = cpu_to_be32(ring->bf.uar->index);
 
···
 
 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb)
 {
-	struct mlx4_en_priv *priv = netdev_priv(dev);
 	u16 vlan_tag = 0;
 
-	/* If we support per priority flow control and the packet contains
-	 * a vlan tag, send the packet to the TX ring assigned to that priority
-	 */
-	if (priv->prof->rx_ppp && vlan_tx_tag_present(skb)) {
+	if (vlan_tx_tag_present(skb)) {
 		vlan_tag = vlan_tx_tag_get(skb);
 		return MLX4_EN_NUM_TX_RINGS + (vlan_tag >> 13);
 	}
 
-	return skb_tx_hash(dev, skb);
+	return __skb_tx_hash(dev, skb, MLX4_EN_NUM_TX_RINGS);
 }
 
 static void mlx4_bf_copy(void __iomem *dst, unsigned long *src, unsigned bytecnt)

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

···
 void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv, struct mlx4_en_tx_ring *ring);
 int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
 			     struct mlx4_en_tx_ring *ring,
-			     int cq);
+			     int cq, int user_prio);
 void mlx4_en_deactivate_tx_ring(struct mlx4_en_priv *priv,
 				struct mlx4_en_tx_ring *ring);
 
···
 			  int budget);
 int mlx4_en_poll_rx_cq(struct napi_struct *napi, int budget);
 void mlx4_en_fill_qp_context(struct mlx4_en_priv *priv, int size, int stride,
-			     int is_tx, int rss, int qpn, int cqn,
-			     struct mlx4_qp_context *context);
+		int is_tx, int rss, int qpn, int cqn, int user_prio,
+		struct mlx4_qp_context *context);
 void mlx4_en_sqp_event(struct mlx4_qp *qp, enum mlx4_event event);
 int mlx4_en_map_buffer(struct mlx4_buf *buf);
 void mlx4_en_unmap_buffer(struct mlx4_buf *buf);

include/linux/mlx4/qp.h

···
 	u8			rgid[16];
 	u8			sched_queue;
 	u8			vlan_index;
-	u8			reserved3[2];
+	u8			feup;
+	u8			reserved3;
 	u8			reserved4[2];
 	u8			dmac[6];
 };