RDMA/nes: Make poll_cq return correct number of wqes during flush

When a flush request is given to the hw, it will place one cqe marked
as flushed (unless there is nothing to flush).  An application that is
waiting for all wqe's to complete will be left hanging.  This modifies
poll_cq to return the correct number of flushes for the pending
elements on the wq.
Signed-off-by: Don Wood <donald.e.wood@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/nes/nes_verbs.c

@@ -3615,11 +3615,13 @@ static int nes_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 	struct nes_qp *nesqp;
 	struct nes_hw_cqe cqe;
 	u32 head;
-	u32 wq_tail;
+	u32 wq_tail = 0;
 	u32 cq_size;
 	u32 cqe_count = 0;
 	u32 wqe_index;
 	u32 u32temp;
+	u32 move_cq_head = 1;
+	u32 err_code;
 
 	nes_debug(NES_DBG_CQ, "\n");
 
@@ -3640,7 +3642,6 @@ static int nes_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 		rmb();
 
 		cqe = nescq->hw_cq.cq_vbase[head];
-		nescq->hw_cq.cq_vbase[head].cqe_words[NES_CQE_OPCODE_IDX] = 0;
 		u32temp = le32_to_cpu(cqe.cqe_words[NES_CQE_COMP_COMP_CTX_LOW_IDX]);
 		wqe_index = u32temp & (nesdev->nesadapter->max_qp_wr - 1);
 		u32temp &= ~(NES_SW_CONTEXT_ALIGN-1);
@@ -3667,16 +3668,14 @@ static int nes_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 				}
 
 				/* Working on a SQ Completion*/
-				wq_tail = wqe_index;
-				nesqp->hwqp.sq_tail = (wqe_index+1)&(nesqp->hwqp.sq_size - 1);
-				wrid = (((u64)(cpu_to_le32((u32)nesqp->hwqp.sq_vbase[wq_tail].
+				wrid = (((u64)(cpu_to_le32((u32)nesqp->hwqp.sq_vbase[wqe_index].
 						wqe_words[NES_IWARP_SQ_WQE_COMP_SCRATCH_HIGH_IDX]))) << 32) |
-						((u64)(cpu_to_le32((u32)nesqp->hwqp.sq_vbase[wq_tail].
+						((u64)(cpu_to_le32((u32)nesqp->hwqp.sq_vbase[wqe_index].
 						wqe_words[NES_IWARP_SQ_WQE_COMP_SCRATCH_LOW_IDX])));
-				entry->byte_len = le32_to_cpu(nesqp->hwqp.sq_vbase[wq_tail].
+				entry->byte_len = le32_to_cpu(nesqp->hwqp.sq_vbase[wqe_index].
 						wqe_words[NES_IWARP_SQ_WQE_TOTAL_PAYLOAD_IDX]);
 
-				switch (le32_to_cpu(nesqp->hwqp.sq_vbase[wq_tail].
+				switch (le32_to_cpu(nesqp->hwqp.sq_vbase[wqe_index].
 						wqe_words[NES_IWARP_SQ_WQE_MISC_IDX]) & 0x3f) {
 					case NES_IWARP_SQ_OP_RDMAW:
 						nes_debug(NES_DBG_CQ, "Operation = RDMA WRITE.\n");
@@ -3685,7 +3684,7 @@ static int nes_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 					case NES_IWARP_SQ_OP_RDMAR:
 						nes_debug(NES_DBG_CQ, "Operation = RDMA READ.\n");
 						entry->opcode = IB_WC_RDMA_READ;
-						entry->byte_len = le32_to_cpu(nesqp->hwqp.sq_vbase[wq_tail].
+						entry->byte_len = le32_to_cpu(nesqp->hwqp.sq_vbase[wqe_index].
 								wqe_words[NES_IWARP_SQ_WQE_RDMA_LENGTH_IDX]);
 						break;
 					case NES_IWARP_SQ_OP_SENDINV:
@@ -3696,14 +3695,24 @@ static int nes_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 						entry->opcode = IB_WC_SEND;
 						break;
 				}
+
+				nesqp->hwqp.sq_tail = (wqe_index+1)&(nesqp->hwqp.sq_size - 1);
+				if ((entry->status != IB_WC_SUCCESS) && (nesqp->hwqp.sq_tail != nesqp->hwqp.sq_head)) {
+					move_cq_head = 0;
+					wq_tail = nesqp->hwqp.sq_tail;
+				}
 			} else {
 				/* Working on a RQ Completion*/
-				wq_tail = wqe_index;
-					nesqp->hwqp.rq_tail = (wqe_index+1)&(nesqp->hwqp.rq_size - 1);
 				entry->byte_len = le32_to_cpu(cqe.cqe_words[NES_CQE_PAYLOAD_LENGTH_IDX]);
-				wrid = ((u64)(le32_to_cpu(nesqp->hwqp.rq_vbase[wq_tail].wqe_words[NES_IWARP_RQ_WQE_COMP_SCRATCH_LOW_IDX]))) |
-					((u64)(le32_to_cpu(nesqp->hwqp.rq_vbase[wq_tail].wqe_words[NES_IWARP_RQ_WQE_COMP_SCRATCH_HIGH_IDX]))<<32);
+				wrid = ((u64)(le32_to_cpu(nesqp->hwqp.rq_vbase[wqe_index].wqe_words[NES_IWARP_RQ_WQE_COMP_SCRATCH_LOW_IDX]))) |
+					((u64)(le32_to_cpu(nesqp->hwqp.rq_vbase[wqe_index].wqe_words[NES_IWARP_RQ_WQE_COMP_SCRATCH_HIGH_IDX]))<<32);
 					entry->opcode = IB_WC_RECV;
+
+				nesqp->hwqp.rq_tail = (wqe_index+1)&(nesqp->hwqp.rq_size - 1);
+				if ((entry->status != IB_WC_SUCCESS) && (nesqp->hwqp.rq_tail != nesqp->hwqp.rq_head)) {
+					move_cq_head = 0;
+					wq_tail = nesqp->hwqp.rq_tail;
+				}
 			}
 
 			entry->wr_id = wrid;
@@ -3711,18 +3720,28 @@ static int nes_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
 			cqe_count++;
 		}
 
-		if (++head >= cq_size)
-			head = 0;
-		nescq->polled_completions++;
+		if (move_cq_head) {
+			nescq->hw_cq.cq_vbase[head].cqe_words[NES_CQE_OPCODE_IDX] = 0;
+			if (++head >= cq_size)
+				head = 0;
+			nescq->polled_completions++;
 
-		if ((nescq->polled_completions > (cq_size / 2)) ||
-				(nescq->polled_completions == 255)) {
-			nes_debug(NES_DBG_CQ, "CQ%u Issuing CQE Allocate since more than half of cqes"
+			if ((nescq->polled_completions > (cq_size / 2)) ||
+					(nescq->polled_completions == 255)) {
+				nes_debug(NES_DBG_CQ, "CQ%u Issuing CQE Allocate since more than half of cqes"
 					" are pending %u of %u.\n",
 					nescq->hw_cq.cq_number, nescq->polled_completions, cq_size);
-			nes_write32(nesdev->regs+NES_CQE_ALLOC,
+				nes_write32(nesdev->regs+NES_CQE_ALLOC,
 					nescq->hw_cq.cq_number | (nescq->polled_completions << 16));
-			nescq->polled_completions = 0;
+				nescq->polled_completions = 0;
+			}
+		} else {
+			/* Update the wqe index and set status to flush */
+			wqe_index = le32_to_cpu(cqe.cqe_words[NES_CQE_COMP_COMP_CTX_LOW_IDX]);
+			wqe_index = (wqe_index & (~(nesdev->nesadapter->max_qp_wr - 1))) | wq_tail;
+			nescq->hw_cq.cq_vbase[head].cqe_words[NES_CQE_COMP_COMP_CTX_LOW_IDX] =
+				cpu_to_le32(wqe_index);
+			move_cq_head = 1; /* ready for next pass */
 		}
 	}