This is required for upcoming UNMAP implementation. Change-Id: I81fb744e0813121cebd64aa60a03a80bfbecc94d Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com> Reviewed-on: https://review.gerrithub.io/377421 Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com> Tested-by: SPDK Automated Test System <sys_sgsw@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com>