[ofa-general] [PATCH] libmlx4: adjust max_recv_wr capability to be non-zero for non-SRQ qp's

[Jack Morgenstein]

max_recv_wr must also be non-zero for QPs which are not
associated with an SRQ.

Signed-off-by: Jack Morgenstein <jackm at dev.mellanox.co.il>

---

Roland,

Without this patch, if the user requested max_recv_wr = 0,
this will be passed as-is to the kernel layer.

In the kernel, the create-qp will fail because of the (correct) check in
file: drivers/infiniband/hw/mlx4/qp.c, procedure set_rq_size():

		/* HW requires >= 1 RQ entry with >= 1 gather entry */
		if (is_user && (!cap->max_recv_wr || !cap->max_recv_sge))
			return -EINVAL;

In the patch, I added the adjustment after:

	qp->rq.wqe_cnt = align_queue_size(attr->cap.max_recv_wr);

since the align_queue_size macro yields the same result for 1 as it
does for 0.

Index: libmlx4/src/verbs.c
===================================================================
--- libmlx4.orig/src/verbs.c	2007-09-06 16:29:36.000000000 +0300
+++ libmlx4/src/verbs.c	2007-09-06 16:34:55.032294000 +0300
@@ -367,8 +367,12 @@ struct ibv_qp *mlx4_create_qp(struct ibv
 
 	if (attr->srq)
 		attr->cap.max_recv_wr = qp->rq.wqe_cnt = 0;
-	else if (attr->cap.max_recv_sge < 1)
-		attr->cap.max_recv_sge = 1;
+	else {
+		if (attr->cap.max_recv_sge < 1)
+			attr->cap.max_recv_sge = 1;
+		if (attr->cap.max_recv_wr < 1)
+			attr->cap.max_recv_wr = 1;
+	}
 
 	if (mlx4_alloc_qp_buf(pd, &attr->cap, attr->qp_type, qp))
 		goto err;