Mindy McCready -- Porn Studio Slams Brakes on Sex Tape

A major porn studio has pulled the plug on Mindy McCready's sex tape -- immediately ceasing all DVD distribution of the footage in the wake of the singer's suicide ... TMZ has learned.

Vivid Entertainment honcho Steve Hirsch tells TMZ, the DVD distribution freeze is effective at once and will continue indefinitely. The porn company currently has no plans to resume distribution.

The tape "Baseball Mistress" -- which features McCready and her boyfriend at the time -- was originally released by Vivid in 2010, following the singer's stint on "Celebrity Rehab." It's unclear when the actual footage was shot.

In the tape, McCready discusses her alleged affair with married MLB legend Roger Clemens ... hence the title. McCready said she never authorized the tape's release.

As for digital distribution -- Hirsch said that's harder to regulate ... but he plans to pull all digital copies of the video from the Vivid website asap.

As we reported, McCready was found dead at her home in Arkansas Sunday after suffering what appeared to be a self-inflicted gunshot wound. She was 37.