The majority voted in favour of a motion to disallow Migration Legislation Amendment (2017 Measures No. 4) Regulations 2017, which means they'll no longer have any legal force.
What did the Regulations do?
Greens Senator Nick McKim (Tas) explained that:
This regulation which we are seeking to disallow would provide the Minister for Immigration and Border Protection with sweeping new powers on top of what the Australian Greens already consider to be a far too broad range of powers, which have been exercised continually in an unreasonable way by the minister.
The changes that the minister is proposing to make, in broad terms, would allow the immigration department to detain people, potentially indefinitely, on the basis of criminal conduct that has not been proven or even tried, on the basis of behaviour that's considered by the department to have endangered or threatened another person extending, potentially, to bullying and online vilification, and because of inconsistencies in people's names on identity documents issued by any Commonwealth, state or territory government authority or official, or failures to update any name changes in those documents.
See the explanatory memorandum for more information about what these Regulations did.