netfilter: nft_set_pipapo: prepare destroy function for on-demand clone
Once priv->clone can be NULL in case no insertions/removals occurred
in the last transaction we need to drop set elements from priv->match
if priv->clone is NULL.
While at it, condense this function by reusing the pipapo_free_match
helper instead of open-coded version.
The rcu_barrier() is removed, its not needed: old call_rcu instances
for pipapo_reclaim_match do not access struct nft_set.
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>