netfilter: nf_tables: add direct calls for all builtin expressions

With CONFIG_RETPOLINE its faster to add an if (ptr == &foo_func)
check and and use direct calls for all the built-in expressions.

~15% improvement in pathological cases.

checkpatch doesn't like the X macro due to the embedded return statement,
but the macro has a very limited scope so I don't think its a problem.

I would like to avoid bugs of the form
  If (e->ops->eval == (unsigned long)nft_foo_eval)
	 nft_bar_eval();

and open-coded if ()/else if()/else cascade, thus the macro.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/netfilter/nft_bitwise.c b/net/netfilter/nft_bitwise.c
index fff8073e2a56..2c75b9e0474e 100644
--- a/net/netfilter/nft_bitwise.c
+++ b/net/netfilter/nft_bitwise.c
@@ -25,9 +25,8 @@ struct nft_bitwise {
 	struct nft_data		xor;
 };
 
-static void nft_bitwise_eval(const struct nft_expr *expr,
-			     struct nft_regs *regs,
-			     const struct nft_pktinfo *pkt)
+void nft_bitwise_eval(const struct nft_expr *expr,
+		      struct nft_regs *regs, const struct nft_pktinfo *pkt)
 {
 	const struct nft_bitwise *priv = nft_expr_priv(expr);
 	const u32 *src = &regs->data[priv->sreg];