MLP and PTP reporting K-1 and 8949. Do I report the sale of partnership stock (K1 sold all shares) if it was reported as a profit against my losses on my brokerage 1099B.

I don't know purchase price, only cost basis. I sold the entire position and read I have to report cost basis to IRS but if it's being reported on 1099 B then entering it in K1 section of TT would be double counting.