RDMA/rxe: Improve loopback marking

Currently a packet is marked for loopback only if the source and
destination addresses equals. This is not enough when multiple gids are
present in rxe device's gid table and the traffic is from one gid to
another. Fix it by marking the packet for loopback if the destination MAC
address is equal to the source MAC address.
Signed-off-by: Kamal Heib <kamalheib1@gmail.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Tested-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rxe/rxe_av.c

@@ -38,6 +38,7 @@ void rxe_init_av(struct rdma_ah_attr *attr, struct rxe_av *av)
 {
 	rxe_av_from_attr(rdma_ah_get_port_num(attr), av, attr);
 	rxe_av_fill_ip_info(av, attr);
+	memcpy(av->dmac, attr->roce.dmac, ETH_ALEN);
 }
 
 int rxe_av_chk_attr(struct rxe_dev *rxe, struct rdma_ah_attr *attr)

drivers/infiniband/sw/rxe/rxe_net.c

@@ -384,9 +384,6 @@ static int prepare4(struct rxe_pkt_info *pkt, struct sk_buff *skb,
 		return -EHOSTUNREACH;
 	}
 
-	if (!memcmp(saddr, daddr, sizeof(*daddr)))
-		pkt->mask |= RXE_LOOPBACK_MASK;
-
 	prepare_udp_hdr(skb, cpu_to_be16(qp->src_port),
 			cpu_to_be16(ROCE_V2_UDP_DPORT));
 
@@ -411,9 +408,6 @@ static int prepare6(struct rxe_pkt_info *pkt, struct sk_buff *skb,
 		return -EHOSTUNREACH;
 	}
 
-	if (!memcmp(saddr, daddr, sizeof(*daddr)))
-		pkt->mask |= RXE_LOOPBACK_MASK;
-
 	prepare_udp_hdr(skb, cpu_to_be16(qp->src_port),
 			cpu_to_be16(ROCE_V2_UDP_DPORT));
 
@@ -437,6 +431,9 @@ int rxe_prepare(struct rxe_pkt_info *pkt, struct sk_buff *skb, u32 *crc)
 
 	*crc = rxe_icrc_hdr(pkt, skb);
 
+	if (ether_addr_equal(skb->dev->dev_addr, av->dmac))
+		pkt->mask |= RXE_LOOPBACK_MASK;
+
 	return err;
 }
 

include/uapi/rdma/rdma_user_rxe.h

@@ -58,8 +58,7 @@ struct rxe_global_route {
 struct rxe_av {
 	__u8			port_num;
 	__u8			network_type;
-	__u16			reserved1;
-	__u32			reserved2;
+	__u8			dmac[6];
 	struct rxe_global_route	grh;
 	union {
 		struct sockaddr_in	_sockaddr_in;