There are quite a few ways you could do this. I'd probably do it this way:
Duplicate the background texture
Copy it to clipboard
Select > All or Cmd+A
Edit > Copy or Cmd+C
Create an empty Layer mask. Layer > Layer mask > Reveal all.
Alt+Left click the Layer mask thumbnail
This lets you see what's inside the Layer mask, which is just white at the moment )
Edit > Paste or Cmd+V
You can Alt+Left click the Layer mask thumbnail again to get back to normal.
Make sure you have the Layer mask thumbnail selected and do Image > Adjustments > Levels... or Cmd+L
You'll want to bring the upper black arrow to the right for as long as you still have some graininess going on and then continue to do fine adjustment. Perhaps pull it back a bit and/or adjust the grey and white arrow if needed. This all highly depends on your original texture.