  Let $G$ be a connected reductive group over a non-archimedean local field $F$
of residue characteristic $p$, $P$ be a parabolic subgroup of $G$, and $R$ be a
commutative ring. When $R$ is artinian, $p$ is nilpotent in $R$, and
$\mathrm{char}(F)=p$, we prove that the ordinary part functor $\mathrm{Ord}_P$
is exact on the category of admissible smooth $R$-representations of $G$. We
derive some results on Yoneda extensions between admissible smooth
$R$-representations of $G$.
