RDMA/rxe: Implement RC RDMA FLUSH service in requester side

Implement FLUSH request operation in the requester.

Link: https://lore.kernel.org/r/20221206130201.30986-7-lizhijian@fujitsu.comReviewed-by: NZhu Yanjun <zyjzyj2000@gmail.com>
Signed-off-by: NLi Zhijian <lizhijian@fujitsu.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/sw/rxe/rxe_req.c

@@ -241,6 +241,9 @@ static int next_opcode_rc(struct rxe_qp *qp, u32 opcode, int fits)
 				IB_OPCODE_RC_SEND_ONLY_WITH_IMMEDIATE :
 				IB_OPCODE_RC_SEND_FIRST;
 
+	case IB_WR_FLUSH:
+		return IB_OPCODE_RC_FLUSH;
+
 	case IB_WR_RDMA_READ:
 		return IB_OPCODE_RC_RDMA_READ_REQUEST;
 
@@ -425,11 +428,18 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
 
 	/* init optional headers */
 	if (pkt->mask & RXE_RETH_MASK) {
+		if (pkt->mask & RXE_FETH_MASK)
+			reth_set_rkey(pkt, ibwr->wr.flush.rkey);
+		else
 			reth_set_rkey(pkt, ibwr->wr.rdma.rkey);
 		reth_set_va(pkt, wqe->iova);
 		reth_set_len(pkt, wqe->dma.resid);
 	}
 
+	/* Fill Flush Extension Transport Header */
+	if (pkt->mask & RXE_FETH_MASK)
+		feth_init(pkt, ibwr->wr.flush.type, ibwr->wr.flush.level);
+
 	if (pkt->mask & RXE_IMMDT_MASK)
 		immdt_set_imm(pkt, ibwr->ex.imm_data);
 
@@ -488,6 +498,9 @@ static int finish_packet(struct rxe_qp *qp, struct rxe_av *av,
 
 			memset(pad, 0, bth_pad(pkt));
 		}
+	} else if (pkt->mask & RXE_FLUSH_MASK) {
+		/* oA19-2: shall have no payload. */
+		wqe->dma.resid = 0;
 	}
 
 	if (pkt->mask & RXE_ATOMIC_WRITE_MASK) {