netfilter: nf_tables: avoid retpoline overhead for some ct expression calls

nft_ct expression cannot be made builtin to nf_tables without also
forcing the conntrack itself to be builtin.

However, this can be avoided by splitting retrieval of a few
selector keys that only need to access the nf_conn structure,
i.e. no function calls to nf_conntrack code.

Many rulesets start with something like
"ct status established,related accept"

With this change, this no longer requires an indirect call, which
gives about 1.8% more throughput with a simple conntrack-enabled
forwarding test (retpoline thunk used).

Signed-off-by: Florian Westphal <fw@strlen.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c
index d9992906199f..6ecd0ba2e546 100644
--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -228,6 +228,9 @@ static void expr_call_ops_eval(const struct nft_expr *expr,
 	X(e, nft_counter_eval);
 	X(e, nft_meta_get_eval);
 	X(e, nft_lookup_eval);
+#if IS_ENABLED(CONFIG_NFT_CT)
+	X(e, nft_ct_get_fast_eval);
+#endif
 	X(e, nft_range_eval);
 	X(e, nft_immediate_eval);
 	X(e, nft_byteorder_eval);