IB/rxe: vary the source udp port for receive scaling

Select the source udp port number for a QP based on the
source QPN. This provides a better spread of traffic
across NIC RX queues for RC/UC QPs.
Signed-off-by: Vijay Immanuel <vijayi@attalasystems.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/sw/rxe/rxe_net.c

@@ -396,8 +396,8 @@ static int prepare4(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
 	if (!memcmp(saddr, daddr, sizeof(*daddr)))
 		pkt->mask |= RXE_LOOPBACK_MASK;
 
-	prepare_udp_hdr(skb, htons(RXE_ROCE_V2_SPORT),
-			htons(ROCE_V2_UDP_DPORT));
+	prepare_udp_hdr(skb, cpu_to_be16(qp->src_port),
+			cpu_to_be16(ROCE_V2_UDP_DPORT));
 
 	prepare_ipv4_hdr(dst, skb, saddr->s_addr, daddr->s_addr, IPPROTO_UDP,
 			 av->grh.traffic_class, av->grh.hop_limit, df, xnet);
@@ -423,8 +423,8 @@ static int prepare6(struct rxe_dev *rxe, struct rxe_pkt_info *pkt,
 	if (!memcmp(saddr, daddr, sizeof(*daddr)))
 		pkt->mask |= RXE_LOOPBACK_MASK;
 
-	prepare_udp_hdr(skb, htons(RXE_ROCE_V2_SPORT),
-			htons(ROCE_V2_UDP_DPORT));
+	prepare_udp_hdr(skb, cpu_to_be16(qp->src_port),
+			cpu_to_be16(ROCE_V2_UDP_DPORT));
 
 	prepare_ipv6_hdr(dst, skb, saddr, daddr, IPPROTO_UDP,
 			 av->grh.traffic_class,

drivers/infiniband/sw/rxe/rxe_qp.c

@@ -227,6 +227,16 @@ static int rxe_qp_init_req(struct rxe_dev *rxe, struct rxe_qp *qp,
 		return err;
 	qp->sk->sk->sk_user_data = qp;
 
+	/* pick a source UDP port number for this QP based on
+	 * the source QPN. this spreads traffic for different QPs
+	 * across different NIC RX queues (while using a single
+	 * flow for a given QP to maintain packet order).
+	 * the port number must be in the Dynamic Ports range
+	 * (0xc000 - 0xffff).
+	 */
+	qp->src_port = RXE_ROCE_V2_SPORT +
+		(hash_32_generic(qp_num(qp), 14) & 0x3fff);
+
 	qp->sq.max_wr		= init->cap.max_send_wr;
 	qp->sq.max_sge		= init->cap.max_send_sge;
 	qp->sq.max_inline	= init->cap.max_inline_data;

drivers/infiniband/sw/rxe/rxe_verbs.h

@@ -248,6 +248,7 @@ struct rxe_qp {
 
 	struct socket		*sk;
 	u32			dst_cookie;
+	u16			src_port;
 
 	struct rxe_av		pri_av;
 	struct rxe_av		alt_av;