[openib-general] [PATCH] CMA: allow/require bind before connect

[Michael S. Tsirkin]

Sean, CMA currently bails out if I bind to ANY address before connect.
I think in TCP you bind before connect and if not it autobinds for you
(see our discussion for legal port range for autobind).
The reason it fails is here:


        id_priv = container_of(id, struct rdma_id_private, id);
        if (id_priv->cma_dev) {
                expected_state = CMA_ADDR_BOUND;
                src_addr = &id->route.addr.src_addr;
        } else
                expected_state = CMA_IDLE;

        if (!cma_comp_exch(id_priv, expected_state, CMA_ADDR_QUERY))
                return -EINVAL;

So apparently, state must be idle unless cma_dev is set, but it's
not set probably because I bind to ANY address.

Not sure what the proper fix would be. Maybe it makes sense to *require*
binding before rdma_resolve_addr, like in TCP?

--

Require bind before connect (could be ANY port).

Signed-off-by: Michael S. Tsirkin <mst at mellanox.co.il>

Index: linux-2.6.16/drivers/infiniband/core/cma.c
===================================================================
--- linux-2.6.16/drivers/infiniband/core/cma.c	(revision 6012)
+++ linux-2.6.16/drivers/infiniband/core/cma.c	(working copy)
@@ -1285,23 +1292,20 @@ int rdma_resolve_addr(struct rdma_cm_id 
 		      struct sockaddr *dst_addr, int timeout_ms)
 {
 	struct rdma_id_private *id_priv;
-	enum cma_state expected_state;
 	int ret;
 
 	id_priv = container_of(id, struct rdma_id_private, id);
 	if (id_priv->cma_dev) {
-		expected_state = CMA_ADDR_BOUND;
 		src_addr = &id->route.addr.src_addr;
-	} else
-		expected_state = CMA_IDLE;
+	}
 
-	if (!cma_comp_exch(id_priv, expected_state, CMA_ADDR_QUERY))
+	if (!cma_comp_exch(id_priv, CMA_ADDR_BOUND, CMA_ADDR_QUERY))
 		return -EINVAL;
 
 	atomic_inc(&id_priv->refcount);
 	memcpy(&id->route.addr.dst_addr, dst_addr, ip_addr_size(dst_addr));
 	if (cma_loopback_addr(dst_addr))
-		ret = cma_resolve_loopback(id_priv, src_addr, expected_state);
+		ret = cma_resolve_loopback(id_priv, src_addr, CMA_ADDR_BOUND);
 	else
 		ret = rdma_resolve_ip(src_addr, dst_addr,
 				      &id->route.addr.dev_addr,
@@ -1311,7 +1315,7 @@ int rdma_resolve_addr(struct rdma_cm_id 
 
 	return 0;
 err:
-	cma_comp_exch(id_priv, CMA_ADDR_QUERY, expected_state);
+	cma_comp_exch(id_priv, CMA_ADDR_QUERY, CMA_ADDR_BOUND);
 	cma_deref_id(id_priv);
 	return ret;
 }


-- 
Michael S. Tsirkin
Staff Engineer, Mellanox Technologies