They need the UP 31 RS seats but they dont come until 2019 which is a problem where it needs the congress for legislative agenda.
RS every 2 years a third of members are up but BJP wont gain anything until 2019 you can do math as well with the states coming up for reelection in 2018 cycle RS.
If they win in 2018 karntaka i think it will help BJP in rajya sabha in 2020 when they come for election in RS.