IB/hfi1: Add a function to receive TID RDMA RESYNC packet

This patch adds a function to receive TID RDMA RESYNC packet on the
responder side. The QP's hardware flow will be updated and all
allocated software flows will be updated accordingly in order to
drop all stale packets.
Signed-off-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@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>

drivers/infiniband/hw/hfi1/tid_rdma.c

@@ -4649,3 +4649,106 @@ u32 hfi1_build_tid_rdma_resync(struct rvt_qp *qp, struct rvt_swqe *wqe,
 
 	return sizeof(ohdr->u.tid_rdma.resync) / sizeof(u32);
 }
+
+void hfi1_rc_rcv_tid_rdma_resync(struct hfi1_packet *packet)
+{
+	struct ib_other_headers *ohdr = packet->ohdr;
+	struct rvt_qp *qp = packet->qp;
+	struct hfi1_qp_priv *qpriv = qp->priv;
+	struct hfi1_ctxtdata *rcd = qpriv->rcd;
+	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
+	struct rvt_ack_entry *e;
+	struct tid_rdma_request *req;
+	struct tid_rdma_flow *flow;
+	struct tid_flow_state *fs = &qpriv->flow_state;
+	u32 psn, generation, idx, gen_next;
+	bool is_fecn;
+	unsigned long flags;
+
+	is_fecn = process_ecn(qp, packet);
+	psn = mask_psn(be32_to_cpu(ohdr->bth[2]));
+
+	generation = mask_psn(psn + 1) >> HFI1_KDETH_BTH_SEQ_SHIFT;
+	spin_lock_irqsave(&qp->s_lock, flags);
+
+	gen_next = (fs->generation == KERN_GENERATION_RESERVED) ?
+		generation : kern_flow_generation_next(fs->generation);
+	/*
+	 * RESYNC packet contains the "next" generation and can only be
+	 * from the current or previous generations
+	 */
+	if (generation != mask_generation(gen_next - 1) &&
+	    generation != gen_next)
+		goto bail;
+	/* Already processing a resync */
+	if (qpriv->resync)
+		goto bail;
+
+	spin_lock(&rcd->exp_lock);
+	if (fs->index >= RXE_NUM_TID_FLOWS) {
+		/*
+		 * If we don't have a flow, save the generation so it can be
+		 * applied when a new flow is allocated
+		 */
+		fs->generation = generation;
+	} else {
+		/* Reprogram the QP flow with new generation */
+		rcd->flows[fs->index].generation = generation;
+		fs->generation = kern_setup_hw_flow(rcd, fs->index);
+	}
+	fs->psn = 0;
+	/*
+	 * Disable SW PSN checking since a RESYNC is equivalent to a
+	 * sync point and the flow has/will be reprogrammed
+	 */
+	qpriv->s_flags &= ~HFI1_R_TID_SW_PSN;
+
+	/*
+	 * Reset all TID flow information with the new generation.
+	 * This is done for all requests and segments after the
+	 * last received segment
+	 */
+	for (idx = qpriv->r_tid_tail; ; idx++) {
+		u16 flow_idx;
+
+		if (idx > rvt_size_atomic(&dev->rdi))
+			idx = 0;
+		e = &qp->s_ack_queue[idx];
+		if (e->opcode == TID_OP(WRITE_REQ)) {
+			req = ack_to_tid_req(e);
+
+			/* start from last unacked segment */
+			for (flow_idx = req->clear_tail;
+			     CIRC_CNT(req->setup_head, flow_idx,
+				      MAX_FLOWS);
+			     flow_idx = CIRC_NEXT(flow_idx, MAX_FLOWS)) {
+				u32 lpsn;
+				u32 next;
+
+				flow = &req->flows[flow_idx];
+				lpsn = full_flow_psn(flow,
+						     flow->flow_state.lpsn);
+				next = flow->flow_state.r_next_psn;
+				flow->npkts = delta_psn(lpsn, next - 1);
+				flow->flow_state.generation = fs->generation;
+				flow->flow_state.spsn = fs->psn;
+				flow->flow_state.lpsn =
+					flow->flow_state.spsn + flow->npkts - 1;
+				flow->flow_state.r_next_psn =
+					full_flow_psn(flow,
+						      flow->flow_state.spsn);
+				fs->psn += flow->npkts;
+			}
+		}
+		if (idx == qp->s_tail_ack_queue)
+			break;
+	}
+
+	spin_unlock(&rcd->exp_lock);
+	qpriv->resync = true;
+	/* RESYNC request always gets a TID RDMA ACK. */
+	qpriv->s_nak_state = 0;
+	qpriv->s_flags |= RVT_S_ACK_PENDING;
+bail:
+	spin_unlock_irqrestore(&qp->s_lock, flags);
+}

drivers/infiniband/hw/hfi1/tid_rdma.h

@@ -296,4 +296,6 @@ u32 hfi1_build_tid_rdma_resync(struct rvt_qp *qp, struct rvt_swqe *wqe,
 			       struct ib_other_headers *ohdr, u32 *bth1,
 			       u32 *bth2, u16 fidx);
 
+void hfi1_rc_rcv_tid_rdma_resync(struct hfi1_packet *packet);
+
 #endif /* HFI1_TID_RDMA_H */