1. dsm_unpin_mapping(dsm_segment *seg) + if (CurrentResourceOwner && IsResourceOwnerReleasing(CurrentResourceOwner)) + return;
Given that the function can return without setting resowner to a CurrentResourceOwner which is not NULL, shall we change the function signature to return true when "unpin" is successful and false when not? This behavior existed earlier too, but adding the check has made it explicit. Although this function is not currently in use, it would be beneficial to make the API more verbose.
2. If value of IsResourceOwnerReleasing changes between dsm_create_descriptor and attach_internal, the dsm segment and dsa area will end up with different resource owners. Earlier the chances of CurrentResourceOwner changing between the two functions were zero. May be something can be done to keep resowner assignments under both these functions in sync.
