RDS/IB: add _to_node() macros for numa and use {k,v}malloc_node()

Allocate send/recv rings in memory that is node-local to the HCA.
This significantly helps performance.

Signed-off-by: Andy Grover <andy.grover@oracle.com>

net/rds/ib.c

@@ -77,7 +77,7 @@ void rds_ib_add_one(struct ib_device *device)
 		goto free_attr;
 	}
 
-	rds_ibdev = kmalloc(sizeof *rds_ibdev, GFP_KERNEL);
+	rds_ibdev = kmalloc_node(sizeof *rds_ibdev, GFP_KERNEL, ibdev_to_node(device));
 	if (!rds_ibdev)
 		goto free_attr;