Finalizes a generalized scatter from one vector to another for GPU based computation. Effectively, this function resets the temporary buffer flags. Currently, this only used in the context of the parallel SpMV call in MatMult_MPIAIJCUSP (in mpi/mpicusp/mpiaijcusp.cu). Once the MatMultAdd is finished, the GPU temporary buffers used for messaging are no longer valid.
PetscErrorCode VecScatterFinalizeForGPU(VecScatter inctx)