Danni Ashe retired from the adult business 2 years ago. She made a few million dollars and sold out her shares in her company which is owned by Penthouse now.
If there is a rich porn star, it's most likely Jenna Jameson. During her boom period in the late 90s, she must have been raking in 7 figures in website subscriptions alone. Not to mention her movie contracts and all the merchandise she sold associated with her name.
However, keep in mind, most porn stars don't make millions of dollars. Most of them either make a few thousand or a perhaps a low 6-figure amount before early retirement. Not everyone makes it big in that business and it grinds up and chews out a lot of them. I've noticed that 80 percent of the women you see in adult film or photo shoots do 2, 3, or 5 things for a few nice paychecks and then get out.