[ofa-general] [PATCH v2] rdma_cm: create cm id even when port is down

[Yossi Etigin]

 When doing rdma_resolve_addr() and relevant port is down, the function fails
and rdma_cm id is not bound to the device. Therefore, application does not have
device handle and cannot wait for the port to become active. The function
fails because ipoib is not joined to the multicast group and therefore sa does 
not have a multicast record to take a qkey from.
 The proposed patch is to make lazy qkey resolution - cma_set_qkey will set 
id_priv->qkey if it was not set, and will be called just before the qkey is
really required.

Signed-off-by: Yossi Etigin <yosefe at voltaire.com>

---
Changes from v1:
- fix a missing return value in cma_set_qkey()


drivers/infiniband/core/cma.c |   41 +++++++++++++++++++++++++++--------------
1 file changed, 27 insertions(+), 14 deletions(-)

Index: b/drivers/infiniband/core/cma.c
===================================================================
--- a/drivers/infiniband/core/cma.c	2009-03-30 18:27:36.000000000 +0300
+++ b/drivers/infiniband/core/cma.c	2009-03-30 19:01:30.000000000 +0300
@@ -297,21 +297,25 @@ static void cma_detach_from_dev(struct r
	id_priv->cma_dev = NULL;
}

-static int cma_set_qkey(struct ib_device *device, u8 port_num,
-			enum rdma_port_space ps,
-			struct rdma_dev_addr *dev_addr, u32 *qkey)
+static int cma_set_qkey(struct rdma_id_private *id_priv)
{
	struct ib_sa_mcmember_rec rec;
	int ret = 0;

-	switch (ps) {
+	if (id_priv->qkey)
+		return 0;
+
+	switch (id_priv->id.ps) {
	case RDMA_PS_UDP:
-		*qkey = RDMA_UDP_QKEY;
+		id_priv->qkey = RDMA_UDP_QKEY;
		break;
	case RDMA_PS_IPOIB:
-		ib_addr_get_mgid(dev_addr, &rec.mgid);
-		ret = ib_sa_get_mcmember_rec(device, port_num, &rec.mgid, &rec);
-		*qkey = be32_to_cpu(rec.qkey);
+		ib_addr_get_mgid(&id_priv->id.route.addr.dev_addr, &rec.mgid);
+		ret = ib_sa_get_mcmember_rec(id_priv->id.device,
+					     id_priv->id.port_num, &rec.mgid,
+					     &rec);
+		if (!ret)
+			id_priv->qkey = be32_to_cpu(rec.qkey);
		break;
	default:
		break;
@@ -341,12 +345,7 @@ static int cma_acquire_dev(struct rdma_i
		ret = ib_find_cached_gid(cma_dev->device, &gid,
					 &id_priv->id.port_num, NULL);
		if (!ret) {
-			ret = cma_set_qkey(cma_dev->device,
-					   id_priv->id.port_num,
-					   id_priv->id.ps, dev_addr,
-					   &id_priv->qkey);
-			if (!ret)
-				cma_attach_to_dev(id_priv, cma_dev);
+			cma_attach_to_dev(id_priv, cma_dev);
			break;
		}
	}
@@ -578,6 +577,10 @@ static int cma_ib_init_qp_attr(struct rd
	*qp_attr_mask = IB_QP_STATE | IB_QP_PKEY_INDEX | IB_QP_PORT;

	if (cma_is_ud_ps(id_priv->id.ps)) {
+		ret = cma_set_qkey(id_priv);
+		if (ret)
+			return ret;
+
		qp_attr->qkey = id_priv->qkey;
		*qp_attr_mask |= IB_QP_QKEY;
	} else {
@@ -2201,6 +2204,12 @@ static int cma_sidr_rep_handler(struct i
			event.status = ib_event->param.sidr_rep_rcvd.status;
			break;
		}
+		ret = cma_set_qkey(id_priv);
+		if (ret) {
+			event.event = RDMA_CM_EVENT_ADDR_ERROR;
+			event.status = -EINVAL;
+			break;
+		}
		if (id_priv->qkey != rep->qkey) {
			event.event = RDMA_CM_EVENT_UNREACHABLE;
			event.status = -EINVAL;
@@ -2480,10 +2489,14 @@ static int cma_send_sidr_rep(struct rdma
			     const void *private_data, int private_data_len)
{
	struct ib_cm_sidr_rep_param rep;
+	int ret;

	memset(&rep, 0, sizeof rep);
	rep.status = status;
	if (status == IB_SIDR_SUCCESS) {
+		ret = cma_set_qkey(id_priv);
+		if (ret)
+			return ret;
		rep.qp_num = id_priv->qp_num;
		rep.qkey = id_priv->qkey;
	}

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