IB/hfi1: Unify the software PSN check for TID RDMA READ/WRITE

For expected packet receiving, the hfi1 hardware checks the KDETH PSN
automatically. However, when sequence error occurs, the hfi1 driver can
check the sequence instead until the hardware flow generation is reloaded.

TID RDMA READ and WRITE protocols implement similar software checking
mechanisms, but with different flags and different local variables to
store next expected PSN.

Unify the handling by using only one set of flag and local variable for
both TID RDMA READ and WRITE protocols.
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@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/tid_rdma.c

@@ -67,8 +67,6 @@ static u32 mask_generation(u32 a)
 #define TID_RDMA_DESTQP_FLOW_SHIFT      11
 #define TID_RDMA_DESTQP_FLOW_MASK       0x1f
 
-#define TID_FLOW_SW_PSN BIT(0)
-
 #define TID_OPFN_QP_CTXT_MASK 0xff
 #define TID_OPFN_QP_CTXT_SHIFT 56
 #define TID_OPFN_QP_KDETH_MASK 0xff
@@ -777,7 +775,6 @@ int hfi1_kern_setup_hw_flow(struct hfi1_ctxtdata *rcd, struct rvt_qp *qp)
 		rcd->flows[fs->index].generation = fs->generation;
 	fs->generation = kern_setup_hw_flow(rcd, fs->index);
 	fs->psn = 0;
-	fs->flags = 0;
 	dequeue_tid_waiter(rcd, &rcd->flow_queue, qp);
 	/* get head before dropping lock */
 	fqp = first_qp(rcd, &rcd->flow_queue);
@@ -1808,6 +1805,7 @@ u32 hfi1_build_tid_rdma_read_req(struct rvt_qp *qp, struct rvt_swqe *wqe,
 			goto done;
 
 		hfi1_kern_clear_hw_flow(req->rcd, qp);
+		qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
 		req->state = TID_REQUEST_ACTIVE;
 	}
 
@@ -2476,8 +2474,13 @@ void hfi1_rc_rcv_tid_rdma_read_resp(struct hfi1_packet *packet)
 
 	flow = &req->flows[req->clear_tail];
 	/* When header suppression is disabled */
-	if (cmp_psn(ipsn, flow->flow_state.ib_lpsn))
+	if (cmp_psn(ipsn, flow->flow_state.ib_lpsn)) {
+		if (cmp_psn(kpsn, flow->flow_state.r_next_psn))
+			goto ack_done;
+		flow->flow_state.r_next_psn = mask_psn(kpsn + 1);
 		goto ack_done;
+	}
+	flow->flow_state.r_next_psn = mask_psn(kpsn + 1);
 	req->ack_pending--;
 	priv->pending_tid_r_segs--;
 	qp->s_num_rd_atomic--;
@@ -2519,6 +2522,7 @@ void hfi1_rc_rcv_tid_rdma_read_resp(struct hfi1_packet *packet)
 	     req->comp_seg == req->cur_seg) ||
 	    priv->tid_r_comp == priv->tid_r_reqs) {
 		hfi1_kern_clear_hw_flow(priv->rcd, qp);
+		priv->s_flags &= ~HFI1_R_TID_SW_PSN;
 		if (req->state == TID_REQUEST_SYNC)
 			req->state = TID_REQUEST_ACTIVE;
 	}
@@ -2768,9 +2772,9 @@ static bool handle_read_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 				rvt_rc_error(qp, IB_WC_LOC_QP_OP_ERR);
 				return ret;
 			}
-			if (priv->flow_state.flags & TID_FLOW_SW_PSN) {
+			if (priv->s_flags & HFI1_R_TID_SW_PSN) {
 				diff = cmp_psn(psn,
-					       priv->flow_state.r_next_psn);
+					       flow->flow_state.r_next_psn);
 				if (diff > 0) {
 					if (!(qp->r_flags & RVT_R_RDMAR_SEQ))
 						restart_tid_rdma_read_req(rcd,
@@ -2806,14 +2810,15 @@ static bool handle_read_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 						qp->r_flags &=
 							~RVT_R_RDMAR_SEQ;
 				}
-				priv->flow_state.r_next_psn++;
+				flow->flow_state.r_next_psn =
+					mask_psn(psn + 1);
 			} else {
 				u32 last_psn;
 
 				last_psn = read_r_next_psn(dd, rcd->ctxt,
 							   flow->idx);
-				priv->flow_state.r_next_psn = last_psn;
-				priv->flow_state.flags |= TID_FLOW_SW_PSN;
+				flow->flow_state.r_next_psn = last_psn;
+				priv->s_flags |= HFI1_R_TID_SW_PSN;
 				/*
 				 * If no request has been restarted yet,
 				 * restart the current one.
@@ -2878,6 +2883,7 @@ bool hfi1_handle_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 	struct rvt_ack_entry *e;
 	struct tid_rdma_request *req;
 	struct tid_rdma_flow *flow;
+	int diff = 0;
 
 	trace_hfi1_msg_handle_kdeth_eflags(NULL, "Kdeth error: rhf ",
 					   packet->rhf);
@@ -2977,10 +2983,12 @@ bool hfi1_handle_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 				 * mismatch could be due to packets that were
 				 * already in flight.
 				 */
-				if (psn != flow->flow_state.r_next_psn) {
-					psn = flow->flow_state.r_next_psn;
+				diff = cmp_psn(psn,
+					       flow->flow_state.r_next_psn);
+				if (diff > 0)
 					goto nak_psn;
-				}
+				else if (diff < 0)
+					break;
 
 				qpriv->s_nak_state = 0;
 				/*
@@ -2991,8 +2999,10 @@ bool hfi1_handle_kdeth_eflags(struct hfi1_ctxtdata *rcd,
 				if (psn == full_flow_psn(flow,
 							 flow->flow_state.lpsn))
 					ret = false;
+				flow->flow_state.r_next_psn =
+					mask_psn(psn + 1);
 				qpriv->r_next_psn_kdeth =
-					++flow->flow_state.r_next_psn;
+					flow->flow_state.r_next_psn;
 			}
 			break;
 
@@ -3497,8 +3507,10 @@ static void hfi1_tid_write_alloc_resources(struct rvt_qp *qp, bool intr_ctx)
 		if (qpriv->r_tid_alloc == qpriv->r_tid_head) {
 			/* If all data has been received, clear the flow */
 			if (qpriv->flow_state.index < RXE_NUM_TID_FLOWS &&
-			    !qpriv->alloc_w_segs)
+			    !qpriv->alloc_w_segs) {
 				hfi1_kern_clear_hw_flow(rcd, qp);
+				qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+			}
 			break;
 		}
 
@@ -3524,8 +3536,7 @@ static void hfi1_tid_write_alloc_resources(struct rvt_qp *qp, bool intr_ctx)
 		if (qpriv->sync_pt && !qpriv->alloc_w_segs) {
 			hfi1_kern_clear_hw_flow(rcd, qp);
 			qpriv->sync_pt = false;
-			if (qpriv->s_flags & HFI1_R_TID_SW_PSN)
-				qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+			qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
 		}
 
 		/* Allocate flow if we don't have one */
@@ -4299,7 +4310,7 @@ void hfi1_rc_rcv_tid_rdma_write_data(struct hfi1_packet *packet)
 	if (cmp_psn(psn, full_flow_psn(flow, flow->flow_state.lpsn))) {
 		if (cmp_psn(psn, flow->flow_state.r_next_psn))
 			goto send_nak;
-		flow->flow_state.r_next_psn++;
+		flow->flow_state.r_next_psn = mask_psn(psn + 1);
 		goto exit;
 	}
 	flow->flow_state.r_next_psn = mask_psn(psn + 1);

drivers/infiniband/hw/hfi1/tid_rdma.h

@@ -76,10 +76,8 @@ struct tid_rdma_qp_params {
 struct tid_flow_state {
 	u32 generation;
 	u32 psn;
-	u32 r_next_psn;      /* next PSN to be received (in TID space) */
 	u8 index;
 	u8 last_index;
-	u8 flags;
 };
 
 enum tid_rdma_req_state {

drivers/infiniband/hw/hfi1/trace_tid.h

@@ -53,7 +53,7 @@ u16 hfi1_trace_get_tid_idx(u32 ent);
 			    "tid_r_comp %u pending_tid_r_segs %u " \
 			    "s_flags 0x%x ps_flags 0x%x iow_flags 0x%lx " \
 			    "s_state 0x%x hw_flow_index %u generation 0x%x " \
-			    "fpsn 0x%x flow_flags 0x%x"
+			    "fpsn 0x%x"
 
 #define TID_REQ_PRN "[%s] qpn 0x%x newreq %u opcode 0x%x psn 0x%x lpsn 0x%x " \
 		    "cur_seg %u comp_seg %u ack_seg %u alloc_seg %u " \
@@ -71,7 +71,7 @@ u16 hfi1_trace_get_tid_idx(u32 ent);
 			    "pending_tid_w_segs %u sync_pt %s " \
 			    "ps_nak_psn 0x%x ps_nak_state 0x%x " \
 			    "prnr_nak_state 0x%x hw_flow_index %u generation "\
-			    "0x%x fpsn 0x%x flow_flags 0x%x resync %s" \
+			    "0x%x fpsn 0x%x resync %s" \
 			    "r_next_psn_kdeth 0x%x"
 
 #define TID_WRITE_SENDER_PRN "[%s] qpn 0x%x newreq %u s_tid_cur %u " \
@@ -973,7 +973,6 @@ DECLARE_EVENT_CLASS(/* tid_read_sender */
 		__field(u32, hw_flow_index)
 		__field(u32, generation)
 		__field(u32, fpsn)
-		__field(u32, flow_flags)
 	),
 	TP_fast_assign(/* assign */
 		struct hfi1_qp_priv *priv = qp->priv;
@@ -991,7 +990,6 @@ DECLARE_EVENT_CLASS(/* tid_read_sender */
 		__entry->hw_flow_index = priv->flow_state.index;
 		__entry->generation = priv->flow_state.generation;
 		__entry->fpsn = priv->flow_state.psn;
-		__entry->flow_flags = priv->flow_state.flags;
 	),
 	TP_printk(/* print */
 		TID_READ_SENDER_PRN,
@@ -1007,8 +1005,7 @@ DECLARE_EVENT_CLASS(/* tid_read_sender */
 		__entry->s_state,
 		__entry->hw_flow_index,
 		__entry->generation,
-		__entry->fpsn,
-		__entry->flow_flags
+		__entry->fpsn
 	)
 );
 
@@ -1338,7 +1335,6 @@ DECLARE_EVENT_CLASS(/* tid_write_sp */
 		__field(u32, hw_flow_index)
 		__field(u32, generation)
 		__field(u32, fpsn)
-		__field(u32, flow_flags)
 		__field(bool, resync)
 		__field(u32, r_next_psn_kdeth)
 	),
@@ -1360,7 +1356,6 @@ DECLARE_EVENT_CLASS(/* tid_write_sp */
 		__entry->hw_flow_index = priv->flow_state.index;
 		__entry->generation = priv->flow_state.generation;
 		__entry->fpsn = priv->flow_state.psn;
-		__entry->flow_flags = priv->flow_state.flags;
 		__entry->resync = priv->resync;
 		__entry->r_next_psn_kdeth = priv->r_next_psn_kdeth;
 	),
@@ -1381,7 +1376,6 @@ DECLARE_EVENT_CLASS(/* tid_write_sp */
 		__entry->hw_flow_index,
 		__entry->generation,
 		__entry->fpsn,
-		__entry->flow_flags,
 		__entry->resync ? "yes" : "no",
 		__entry->r_next_psn_kdeth
 	)