SUP-862 Hack to get recursive dp_config_rwlock working in dsl_dataset_hold_ref.
4233 mptsas topo change buffer overflow
Reviewed by: Dan McDonald <danmcd@nexenta.com>
Reviewed by: Kevin Crowe <kevin.crowe@nexenta.com>
Reviewed by: Keith Wesolowski <keith.wesolowski@joyent.com>
Approved by: Robert Mustacchi <rm@joyent.com>
NEX-2167 Null pointer dereference in e_ddi_keep_instance during lun online/attach