RDMA/rxe: Fill in wc byte_len with IB_WC_RECV_RDMA_WITH_IMM

Calculate the correct byte_len on the receiving side when a work
completion is generated with IB_WC_RECV_RDMA_WITH_IMM opcode.

According to the IBA byte_len must indicate the number of written bytes,
whereas it was always equal to zero for the IB_WC_RECV_RDMA_WITH_IMM
opcode, even though data was transferred.

Fixes: 8700e3e7 ("Soft RoCE driver")
Signed-off-by: Konstantin Taranov <konstantin.taranov@inf.ethz.ch>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rxe/rxe_resp.c

@@ -431,6 +431,7 @@ static enum resp_states check_rkey(struct rxe_qp *qp,
 			qp->resp.va = reth_va(pkt);
 			qp->resp.rkey = reth_rkey(pkt);
 			qp->resp.resid = reth_len(pkt);
+			qp->resp.length = reth_len(pkt);
 		}
 		access = (pkt->mask & RXE_READ_MASK) ? IB_ACCESS_REMOTE_READ
 						     : IB_ACCESS_REMOTE_WRITE;
@@ -856,7 +857,9 @@ static enum resp_states do_complete(struct rxe_qp *qp,
 				pkt->mask & RXE_WRITE_MASK) ?
 					IB_WC_RECV_RDMA_WITH_IMM : IB_WC_RECV;
 		wc->vendor_err = 0;
-		wc->byte_len = wqe->dma.length - wqe->dma.resid;
+		wc->byte_len = (pkt->mask & RXE_IMMDT_MASK &&
+				pkt->mask & RXE_WRITE_MASK) ?
+					qp->resp.length : wqe->dma.length - wqe->dma.resid;
 
 		/* fields after byte_len are different between kernel and user
 		 * space

drivers/infiniband/sw/rxe/rxe_verbs.h

@@ -213,6 +213,7 @@ struct rxe_resp_info {
 	struct rxe_mem		*mr;
 	u32			resid;
 	u32			rkey;
+	u32			length;
 	u64			atomic_orig;
 
 	/* SRQ only */