Anthony "Rumble" Johnson's domestic violence case is closed ... the ex-UFC star just cut a deal with prosecutors and won't have to spend more time behind bars.
Johnson was arrested back on May 6 in Palm Beach County, Florida after his girlfriend told cops the former fighter roughed her up during an argument.
In police docs, Johnson said he DID pick the woman up to carry her to a different room because he was tired of arguing ... but he insists he never tried to hurt her.
Johnson was hit with a misdemeanor domestic battery charge .