Depend on how you see it. If you were a devote Communist who hails to Communist Ideals and did not said or do anything against Communism, You were good to go Pray as per You Religion. Celebrate Eid and Fast in Ramazan.
If you come up with "Hey Lets just Implement Sharia in our City" Then their was problem. Or you wanted to promulgate Your beliefs that were against Communism. And that happened to every one in Soviet Union. Christians, Jews Muslims ETC. Soviet Union was not as free as western Countries to Speak out your Ideologies and Criticize the Government or Capitalism.
Also Keep in Mind a Historical Fact, Propaganda Aside, In 1991 Soviet Referendum to decide whether Soviet Union should exist or Not All Muslim Majority States Voted Heavily in Favor of Soviet Union almost 95% Plus majority i.e Kazkahstan, Karghezia ,Uzbekistan, Tukmania, Azerbaijan. While the Cold shoulder came from Predominantly Christian Parts of Soviet Union i.e Byelorussia, Ukarain, Russia etc