Extended the IO descriptors with the ability to group them together in a
parent / child(-ren) relationship. It allows to delay parent completion
until all children are done and enables the children to have additional
context in their completion routines (as opposed to having a single IO
describe all requests).
Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: I6ad111dc231813e397697109a333e2a5d7f5941d
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/449068
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Wojciech Malikowski <wojciech.malikowski@intel.com>
Reviewed-by: Young Tack Jin <youngtack.jin@circuitblvd.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
