IB/hfi1: TID RDMA WRITE should not return IB_WC_RNR_RETRY_EXC_ERR

Normal RDMA WRITE request never returns IB_WC_RNR_RETRY_EXC_ERR to ULPs
because it does not need post receive buffer on the responder side.
Consequently, as an enhancement to normal RDMA WRITE request inside the
hfi1 driver, TID RDMA WRITE request should not return such an error status
to ULPs, although it does receive RNR NAKs from the responder when TID
resources are not available. This behavior is violated when
qp->s_rnr_retry_cnt is set in current hfi1 implementation.

This patch enforces these semantics by avoiding any reaction to the updates
of the RNR QP attributes.

Fixes: 3c6cb20a ("IB/hfi1: Add TID RDMA WRITE functionality into RDMA verbs")
Link: https://lore.kernel.org/r/20191025195842.106825.71532.stgit@awfm-01.aw.intel.com
Cc: <stable@vger.kernel.org>
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hfi1/rc.c

@@ -2209,15 +2209,15 @@ int do_rc_ack(struct rvt_qp *qp, u32 aeth, u32 psn, int opcode,
 		if (qp->s_flags & RVT_S_WAIT_RNR)
 			goto bail_stop;
 		rdi = ib_to_rvt(qp->ibqp.device);
-		if (qp->s_rnr_retry == 0 &&
-		    !((rdi->post_parms[wqe->wr.opcode].flags &
-		      RVT_OPERATION_IGN_RNR_CNT) &&
-		      qp->s_rnr_retry_cnt == 0)) {
+		if (!(rdi->post_parms[wqe->wr.opcode].flags &
+		       RVT_OPERATION_IGN_RNR_CNT)) {
+			if (qp->s_rnr_retry == 0) {
 				status = IB_WC_RNR_RETRY_EXC_ERR;
 				goto class_b;
 			}
 			if (qp->s_rnr_retry_cnt < 7 && qp->s_rnr_retry_cnt > 0)
 				qp->s_rnr_retry--;
+		}
 
 		/*
 		 * The last valid PSN is the previous PSN. For TID RDMA WRITE