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netfilter: nf_tables: remove unneeded conditional 

This helper is inlined, so keep it as small as possible.

If the static key is true, there is only a very small chance
that info->trace is false:

1. tracing was enabled at this very moment, the static key was
   updated to active right after nft_do_table was called.

2. tracing was disabled at this very moment.
   trace->info is already false, the static key is about to
   be patched to false soon.

In both cases, no event will be sent because info->trace
is false (checked in noinline slowpath). info->nf_trace is irrelevant.

The nf_trace update is redunant in this case, but this will only
happen for short duration, when static key flips.

       text  data   bss   dec   hex filename
old:   2980   192    32  3204   c84 nf_tables_core.o
new:   2964   192    32  3188   c74i nf_tables_core.o

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2023-04-14 15:01:31 +02:00 committed by Pablo Neira Ayuso
parent 00c320f9b7
commit 2a1d6abd7e
1 changed files with 2 additions and 4 deletions
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6
net/netfilter/nf_tables_core.c
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@ -67,10 +67,8 @@ static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
static inline void nft_trace_copy_nftrace(const struct nft_pktinfo *pkt, static inline void nft_trace_copy_nftrace(const struct nft_pktinfo *pkt,
struct nft_traceinfo *info) struct nft_traceinfo *info)
{ {
if (static_branch_unlikely(&nft_trace_enabled)) { if (static_branch_unlikely(&nft_trace_enabled))
if (info->trace) info->nf_trace = pkt->skb->nf_trace;
info->nf_trace = pkt->skb->nf_trace;
}
} }
static void nft_bitwise_fast_eval(const struct nft_expr *expr, static void nft_bitwise_fast_eval(const struct nft_expr *expr,