IB/ehca: Fix problem with generated flush work completions

This fix enables ehca device driver to generate flush work completions
even if the application doesn't request completions for all work
requests. The current implementation of ehca will generate flush work
completions for the wrong work requests if an application uses non
signaled work completions.

Signed-off-by: Stefan Roscher <stefan.roscher@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 30 insertions, 21 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_reqs.c b/drivers/infiniband/hw/ehca/ehca_reqs.c
index 64928079eafa..00a648f4316c 100644
--- a/drivers/infiniband/hw/ehca/ehca_reqs.c
+++ b/drivers/infiniband/hw/ehca/ehca_reqs.c
@@ -179,6 +179,7 @@ static inline int ehca_write_swqe(struct ehca_qp *qp,
 
 	qmap_entry->app_wr_id = get_app_wr_id(send_wr->wr_id);
 	qmap_entry->reported = 0;
+	qmap_entry->cqe_req = 0;
 
 	switch (send_wr->opcode) {
 	case IB_WR_SEND:
@@ -203,8 +204,10 @@ static inline int ehca_write_swqe(struct ehca_qp *qp,
 
 	if ((send_wr->send_flags & IB_SEND_SIGNALED ||
 	    qp->init_attr.sq_sig_type == IB_SIGNAL_ALL_WR)
-	    && !hidden)
+	    && !hidden) {
 		wqe_p->wr_flag |= WQE_WRFLAG_REQ_SIGNAL_COM;
+		qmap_entry->cqe_req = 1;
+	}
 
 	if (send_wr->opcode == IB_WR_SEND_WITH_IMM ||
 	    send_wr->opcode == IB_WR_RDMA_WRITE_WITH_IMM) {
@@ -569,6 +572,7 @@ static int internal_post_recv(struct ehca_qp *my_qp,
 		qmap_entry = &my_qp->rq_map.map[rq_map_idx];
 		qmap_entry->app_wr_id = get_app_wr_id(cur_recv_wr->wr_id);
 		qmap_entry->reported = 0;
+		qmap_entry->cqe_req = 1;
 
 		wqe_cnt++;
 	} /* eof for cur_recv_wr */
@@ -706,27 +710,34 @@ repoll:
 		goto repoll;
 	wc->qp = &my_qp->ib_qp;
 
+	qmap_tail_idx = get_app_wr_id(cqe->work_request_id);
+	if (!(cqe->w_completion_flags & WC_SEND_RECEIVE_BIT))
+		/* We got a send completion. */
+		qmap = &my_qp->sq_map;
+	else
+		/* We got a receive completion. */
+		qmap = &my_qp->rq_map;
+
+	/* advance the tail pointer */
+	qmap->tail = qmap_tail_idx;
+
 	if (is_error) {
 		/*
 		 * set left_to_poll to 0 because in error state, we will not
 		 * get any additional CQEs
 		 */
-		ehca_add_to_err_list(my_qp, 1);
+		my_qp->sq_map.next_wqe_idx = (my_qp->sq_map.tail + 1) %
+						my_qp->sq_map.entries;
 		my_qp->sq_map.left_to_poll = 0;
+		ehca_add_to_err_list(my_qp, 1);
 
+		my_qp->rq_map.next_wqe_idx = (my_qp->rq_map.tail + 1) %
+						my_qp->rq_map.entries;
+		my_qp->rq_map.left_to_poll = 0;
 		if (HAS_RQ(my_qp))
 			ehca_add_to_err_list(my_qp, 0);
-		my_qp->rq_map.left_to_poll = 0;
 	}
 
-	qmap_tail_idx = get_app_wr_id(cqe->work_request_id);
-	if (!(cqe->w_completion_flags & WC_SEND_RECEIVE_BIT))
-		/* We got a send completion. */
-		qmap = &my_qp->sq_map;
-	else
-		/* We got a receive completion. */
-		qmap = &my_qp->rq_map;
-
 	qmap_entry = &qmap->map[qmap_tail_idx];
 	if (qmap_entry->reported) {
 		ehca_warn(cq->device, "Double cqe on qp_num=%#x",
@@ -738,10 +749,6 @@ repoll:
 	wc->wr_id = replace_wr_id(cqe->work_request_id, qmap_entry->app_wr_id);
 	qmap_entry->reported = 1;
 
-	/* this is a proper completion, we need to advance the tail pointer */
-	if (++qmap->tail == qmap->entries)
-		qmap->tail = 0;
-
 	/* if left_to_poll is decremented to 0, add the QP to the error list */
 	if (qmap->left_to_poll > 0) {
 		qmap->left_to_poll--;
@@ -805,13 +812,14 @@ static int generate_flush_cqes(struct ehca_qp *my_qp, struct ib_cq *cq,
 	else
 		qmap = &my_qp->rq_map;
 
-	qmap_entry = &qmap->map[qmap->tail];
+	qmap_entry = &qmap->map[qmap->next_wqe_idx];
 
 	while ((nr < num_entries) && (qmap_entry->reported == 0)) {
 		/* generate flush CQE */
+
 		memset(wc, 0, sizeof(*wc));
 
-		offset = qmap->tail * ipz_queue->qe_size;
+		offset = qmap->next_wqe_idx * ipz_queue->qe_size;
 		wqe = (struct ehca_wqe *)ipz_qeit_calc(ipz_queue, offset);
 		if (!wqe) {
 			ehca_err(cq->device, "Invalid wqe offset=%#lx on "
@@ -850,11 +858,12 @@ static int generate_flush_cqes(struct ehca_qp *my_qp, struct ib_cq *cq,
 
 		wc->qp = &my_qp->ib_qp;
 
-		/* mark as reported and advance tail pointer */
+		/* mark as reported and advance next_wqe pointer */
 		qmap_entry->reported = 1;
-		if (++qmap->tail == qmap->entries)
-			qmap->tail = 0;
-		qmap_entry = &qmap->map[qmap->tail];
+		qmap->next_wqe_idx++;
+		if (qmap->next_wqe_idx == qmap->entries)
+			qmap->next_wqe_idx = 0;
+		qmap_entry = &qmap->map[qmap->next_wqe_idx];
 
 		wc++; nr++;
 	}