IB/hfi1: Add functions for restarting TID RDMA READ request

This patch adds functions to retry TID RDMA READ request. Since TID RDMA
READ request could be retried from any segment boundary, it requires
a number of tracking fields in various structures and those fields
should be reset properly. The qp->s_num_rd_atomic field is reset before
retry and therefore should be incremented for each new or retried
RDMA READ or atomic request.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 74 insertions, 20 deletions

diff --git a/drivers/infiniband/hw/hfi1/rc.c b/drivers/infiniband/hw/hfi1/rc.c
index 6e74cd3814b8..e478a0b93eb9 100644
--- a/drivers/infiniband/hw/hfi1/rc.c
+++ b/drivers/infiniband/hw/hfi1/rc.c
@@ -503,16 +503,14 @@ no_flow_control:
 			 * Don't allow more operations to be started
 			 * than the QP limits allow.
 			 */
-			if (newreq) {
-				if (qp->s_num_rd_atomic >=
-				    qp->s_max_rd_atomic) {
-					qp->s_flags |= RVT_S_WAIT_RDMAR;
-					goto bail;
-				}
-				qp->s_num_rd_atomic++;
-				if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
-					qp->s_lsn++;
+			if (qp->s_num_rd_atomic >=
+			    qp->s_max_rd_atomic) {
+				qp->s_flags |= RVT_S_WAIT_RDMAR;
+				goto bail;
 			}
+			qp->s_num_rd_atomic++;
+			if (newreq && !(qp->s_flags & RVT_S_UNLIMITED_CREDIT))
+				qp->s_lsn++;
 			put_ib_reth_vaddr(
 				wqe->rdma_wr.remote_addr,
 				&ohdr->u.rc.reth);
@@ -534,14 +532,12 @@ no_flow_control:
 			 * Don't allow more operations to be started
 			 * than the QP limits allow.
 			 */
-			if (newreq) {
-				if (qp->s_num_rd_atomic >=
-				    qp->s_max_rd_atomic) {
-					qp->s_flags |= RVT_S_WAIT_RDMAR;
-					goto bail;
-				}
-				qp->s_num_rd_atomic++;
+			if (qp->s_num_rd_atomic >=
+			    qp->s_max_rd_atomic) {
+				qp->s_flags |= RVT_S_WAIT_RDMAR;
+				goto bail;
 			}
+			qp->s_num_rd_atomic++;
 
 			/* FALLTHROUGH */
 		case IB_WR_OPFN:
@@ -971,6 +967,43 @@ void hfi1_send_rc_ack(struct hfi1_packet *packet, bool is_fecn)
 }
 
 /**
+ * update_num_rd_atomic - update the qp->s_num_rd_atomic
+ * @qp: the QP
+ * @psn: the packet sequence number to restart at
+ * @wqe: the wqe
+ *
+ * This is called from reset_psn() to update qp->s_num_rd_atomic
+ * for the current wqe.
+ * Called at interrupt level with the QP s_lock held.
+ */
+static void update_num_rd_atomic(struct rvt_qp *qp, u32 psn,
+				 struct rvt_swqe *wqe)
+{
+	u32 opcode = wqe->wr.opcode;
+
+	if (opcode == IB_WR_RDMA_READ ||
+	    opcode == IB_WR_ATOMIC_CMP_AND_SWP ||
+	    opcode == IB_WR_ATOMIC_FETCH_AND_ADD) {
+		qp->s_num_rd_atomic++;
+	} else if (opcode == IB_WR_TID_RDMA_READ) {
+		struct tid_rdma_request *req = wqe_to_tid_req(wqe);
+		struct hfi1_qp_priv *priv = qp->priv;
+
+		if (cmp_psn(psn, wqe->lpsn) <= 0) {
+			u32 cur_seg;
+
+			cur_seg = (psn - wqe->psn) / priv->pkts_ps;
+			req->ack_pending = cur_seg - req->comp_seg;
+			priv->pending_tid_r_segs += req->ack_pending;
+			qp->s_num_rd_atomic += req->ack_pending;
+		} else {
+			priv->pending_tid_r_segs += req->total_segs;
+			qp->s_num_rd_atomic += req->total_segs;
+		}
+	}
+}
+
+/**
  * reset_psn - reset the QP state to send starting from PSN
  * @qp: the QP
  * @psn: the packet sequence number to restart at
@@ -984,9 +1017,12 @@ static void reset_psn(struct rvt_qp *qp, u32 psn)
 	u32 n = qp->s_acked;
 	struct rvt_swqe *wqe = rvt_get_swqe_ptr(qp, n);
 	u32 opcode;
+	struct hfi1_qp_priv *priv = qp->priv;
 
 	lockdep_assert_held(&qp->s_lock);
 	qp->s_cur = n;
+	priv->pending_tid_r_segs = 0;
+	qp->s_num_rd_atomic = 0;
 
 	/*
 	 * If we are starting the request from the beginning,
@@ -996,9 +1032,9 @@ static void reset_psn(struct rvt_qp *qp, u32 psn)
 		qp->s_state = OP(SEND_LAST);
 		goto done;
 	}
+	update_num_rd_atomic(qp, psn, wqe);
 
 	/* Find the work request opcode corresponding to the given PSN. */
-	opcode = wqe->wr.opcode;
 	for (;;) {
 		int diff;
 
@@ -1008,8 +1044,11 @@ static void reset_psn(struct rvt_qp *qp, u32 psn)
 			break;
 		wqe = rvt_get_swqe_ptr(qp, n);
 		diff = cmp_psn(psn, wqe->psn);
-		if (diff < 0)
+		if (diff < 0) {
+			/* Point wqe back to the previous one*/
+			wqe = rvt_get_swqe_ptr(qp, qp->s_cur);
 			break;
+		}
 		qp->s_cur = n;
 		/*
 		 * If we are starting the request from the beginning,
@@ -1019,8 +1058,10 @@ static void reset_psn(struct rvt_qp *qp, u32 psn)
 			qp->s_state = OP(SEND_LAST);
 			goto done;
 		}
-		opcode = wqe->wr.opcode;
+
+		update_num_rd_atomic(qp, psn, wqe);
 	}
+	opcode = wqe->wr.opcode;
 
 	/*
 	 * Set the state to restart in the middle of a request.
@@ -1042,6 +1083,10 @@ static void reset_psn(struct rvt_qp *qp, u32 psn)
 		qp->s_state = OP(RDMA_READ_RESPONSE_MIDDLE);
 		break;
 
+	case IB_WR_TID_RDMA_READ:
+		qp->s_state = TID_OP(READ_RESP);
+		break;
+
 	default:
 		/*
 		 * This case shouldn't happen since its only
@@ -1095,6 +1140,14 @@ void hfi1_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 				wqe = do_rc_completion(qp, wqe, ibp);
 				qp->s_flags &= ~RVT_S_WAIT_ACK;
 			} else {
+				if (wqe->wr.opcode == IB_WR_TID_RDMA_READ) {
+					struct tid_rdma_request *req;
+
+					req = wqe_to_tid_req(wqe);
+					hfi1_kern_exp_rcv_clear_all(req);
+					hfi1_kern_clear_hw_flow(priv->rcd, qp);
+				}
+
 				rvt_send_complete(qp, wqe,
 						  IB_WC_RETRY_EXC_ERR);
 				rvt_error_qp(qp, IB_WC_WR_FLUSH_ERR);
@@ -1108,7 +1161,8 @@ void hfi1_restart_rc(struct rvt_qp *qp, u32 psn, int wait)
 	}
 
 	ibp = to_iport(qp->ibqp.device, qp->port_num);
-	if (wqe->wr.opcode == IB_WR_RDMA_READ)
+	if (wqe->wr.opcode == IB_WR_RDMA_READ ||
+	    wqe->wr.opcode == IB_WR_TID_RDMA_READ)
 		ibp->rvp.n_rc_resends++;
 	else
 		ibp->rvp.n_rc_resends += delta_psn(qp->s_psn, psn);