RDMA/cma: resolve to first active ib port

When we try to resolve a dest addr, if we don't give src addr,
cma core will try to resolve to our source ib device automatically.
The current logic only checks if a given port has the same
subnet_prefix as our dest, which is not enough if we use default
well known subnet_prefix on our active port, as it will be the same
as the subnet_prefix on inactive ports and we might match against
an inactive port by accident. To resolve this, we should also check
if port is active before we resolve it as a suitable src address for
a given dest.

Signed-off-by: Jack Wang <[e-mail]>
Reviewed-by: Michael Wang <[e-mail]>
Acked-by: Sean Hefty <[e-mail]>
Signed-off-by: Doug Ledford <[e-mail]>

drivers/infiniband/core/cma.c

···
 	union ib_gid gid, sgid, *dgid;
 	u16 pkey, index;
 	u8 p;
+	enum ib_port_state port_state;
 	int i;
 
 	cma_dev = NULL;
···
 			if (ib_find_cached_pkey(cur_dev->device, p, pkey, &index))
 				continue;
 
+			if (ib_get_cached_port_state(cur_dev->device, p, &port_state))
+				continue;
 			for (i = 0; !ib_get_cached_gid(cur_dev->device, p, i,
 						       &gid, NULL);
 			     i++) {
···
 				}
 
 				if (!cma_dev && (gid.global.subnet_prefix ==
-						 dgid->global.subnet_prefix)) {
+				    dgid->global.subnet_prefix) &&
+				    port_state == IB_PORT_ACTIVE) {
 					cma_dev = cur_dev;
 					sgid = gid;
 					id_priv->id.port_num = p;