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, 20 insertions, 6 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_qp.c b/drivers/infiniband/hw/ehca/ehca_qp.c
index 9e05ee2db39b..cadbf0cdd910 100644
--- a/drivers/infiniband/hw/ehca/ehca_qp.c
+++ b/drivers/infiniband/hw/ehca/ehca_qp.c
@@ -435,9 +435,13 @@ static void reset_queue_map(struct ehca_queue_map *qmap)
 {
 	int i;
 
-	qmap->tail = 0;
-	for (i = 0; i < qmap->entries; i++)
+	qmap->tail = qmap->entries - 1;
+	qmap->left_to_poll = 0;
+	qmap->next_wqe_idx = 0;
+	for (i = 0; i < qmap->entries; i++) {
 		qmap->map[i].reported = 1;
+		qmap->map[i].cqe_req = 0;
+	}
 }
 
 /*
@@ -1121,6 +1125,7 @@ static int calc_left_cqes(u64 wqe_p, struct ipz_queue *ipz_queue,
 	void *wqe_v;
 	u64 q_ofs;
 	u32 wqe_idx;
+	unsigned int tail_idx;
 
 	/* convert real to abs address */
 	wqe_p = wqe_p & (~(1UL << 63));
@@ -1133,12 +1138,17 @@ static int calc_left_cqes(u64 wqe_p, struct ipz_queue *ipz_queue,
 		return -EFAULT;
 	}
 
+	tail_idx = (qmap->tail + 1) % qmap->entries;
 	wqe_idx = q_ofs / ipz_queue->qe_size;
-	if (wqe_idx < qmap->tail)
-		qmap->left_to_poll = (qmap->entries - qmap->tail) + wqe_idx;
-	else
-		qmap->left_to_poll = wqe_idx - qmap->tail;
 
+	/* check all processed wqes, whether a cqe is requested or not */
+	while (tail_idx != wqe_idx) {
+		if (qmap->map[tail_idx].cqe_req)
+			qmap->left_to_poll++;
+		tail_idx = (tail_idx + 1) % qmap->entries;
+	}
+	/* save index in queue, where we have to start flushing */
+	qmap->next_wqe_idx = wqe_idx;
 	return 0;
 }
 
@@ -1185,10 +1195,14 @@ static int check_for_left_cqes(struct ehca_qp *my_qp, struct ehca_shca *shca)
 	} else {
 		spin_lock_irqsave(&my_qp->send_cq->spinlock, flags);
 		my_qp->sq_map.left_to_poll = 0;
+		my_qp->sq_map.next_wqe_idx = (my_qp->sq_map.tail + 1) %
+						my_qp->sq_map.entries;
 		spin_unlock_irqrestore(&my_qp->send_cq->spinlock, flags);
 
 		spin_lock_irqsave(&my_qp->recv_cq->spinlock, flags);
 		my_qp->rq_map.left_to_poll = 0;
+		my_qp->rq_map.next_wqe_idx = (my_qp->rq_map.tail + 1) %
+						my_qp->rq_map.entries;
 		spin_unlock_irqrestore(&my_qp->recv_cq->spinlock, flags);
 	}