netfilter: nf_tables: do not store pktinfo in traceinfo structure

pass it as argument.  No change in object size.

stack usage decreases by 8 byte:
 nf_tables_core.c:254  nft_do_chain       320     static

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

Author: Florian Westphal

include/net/netfilter/nf_tables.h

@@ -1408,7 +1408,6 @@ void nft_unregister_flowtable_type(struct nf_flowtable_type *type);
  *	@type: event type (enum nft_trace_types)
  *	@skbid: hash of skb to be used as trace id
  *	@packet_dumped: packet headers sent in a previous traceinfo message
- *	@pkt: pktinfo currently processed
  *	@basechain: base chain currently processed
  *	@rule:  rule that was evaluated
  *	@verdict: verdict given by rule
@@ -1419,7 +1418,6 @@ struct nft_traceinfo {
 	bool				packet_dumped;
 	enum nft_trace_types		type:8;
 	u32				skbid;
-	const struct nft_pktinfo	*pkt;
 	const struct nft_base_chain	*basechain;
 	const struct nft_rule_dp	*rule;
 	const struct nft_verdict	*verdict;
@@ -1429,7 +1427,8 @@ void nft_trace_init(struct nft_traceinfo *info, const struct nft_pktinfo *pkt,
 		    const struct nft_verdict *verdict,
 		    const struct nft_chain *basechain);
 
-void nft_trace_notify(struct nft_traceinfo *info);
+void nft_trace_notify(const struct nft_pktinfo *pkt,
+		      struct nft_traceinfo *info);
 
 #define MODULE_ALIAS_NFT_CHAIN(family, name) \
 	MODULE_ALIAS("nft-chain-" __stringify(family) "-" name)

net/netfilter/nf_tables_core.c

@@ -41,15 +41,16 @@ static inline bool nf_skip_indirect_calls(void) { return false; }
 static inline void nf_skip_indirect_calls_enable(void) { }
 #endif
 
-static noinline void __nft_trace_packet(struct nft_traceinfo *info,
+static noinline void __nft_trace_packet(const struct nft_pktinfo *pkt,
+					struct nft_traceinfo *info,
 					enum nft_trace_types type)
 {
 	if (!info->trace || !info->nf_trace)
 		return;
 
 	info->type = type;
 
-	nft_trace_notify(info);
+	nft_trace_notify(pkt, info);
 }
 
 static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
@@ -60,7 +61,7 @@ static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
 	if (static_branch_unlikely(&nft_trace_enabled)) {
 		info->nf_trace = pkt->skb->nf_trace;
 		info->rule = rule;
-		__nft_trace_packet(info, type);
+		__nft_trace_packet(pkt, info, type);
 	}
 }
 
@@ -105,7 +106,8 @@ static void nft_cmp16_fast_eval(const struct nft_expr *expr,
 	regs->verdict.code = NFT_BREAK;
 }
 
-static noinline void __nft_trace_verdict(struct nft_traceinfo *info,
+static noinline void __nft_trace_verdict(const struct nft_pktinfo *pkt,
+					 struct nft_traceinfo *info,
 					 const struct nft_regs *regs)
 {
 	enum nft_trace_types type;
@@ -123,20 +125,21 @@ static noinline void __nft_trace_verdict(struct nft_traceinfo *info,
 		type = NFT_TRACETYPE_RULE;
 
 		if (info->trace)
-			info->nf_trace = info->pkt->skb->nf_trace;
+			info->nf_trace = pkt->skb->nf_trace;
 		break;
 	}
 
-	__nft_trace_packet(info, type);
+	__nft_trace_packet(pkt, info, type);
 }
 
-static inline void nft_trace_verdict(struct nft_traceinfo *info,
+static inline void nft_trace_verdict(const struct nft_pktinfo *pkt,
+				     struct nft_traceinfo *info,
 				     const struct nft_rule_dp *rule,
 				     const struct nft_regs *regs)
 {
 	if (static_branch_unlikely(&nft_trace_enabled)) {
 		info->rule = rule;
-		__nft_trace_verdict(info, regs);
+		__nft_trace_verdict(pkt, info, regs);
 	}
 }
 
@@ -300,7 +303,7 @@ nft_do_chain(struct nft_pktinfo *pkt, void *priv)
 		break;
 	}
 
-	nft_trace_verdict(&info, rule, &regs);
+	nft_trace_verdict(pkt, &info, rule, &regs);
 
 	switch (regs.verdict.code & NF_VERDICT_MASK) {
 	case NF_ACCEPT:

net/netfilter/nf_tables_trace.c

@@ -183,9 +183,9 @@ static const struct nft_chain *nft_trace_get_chain(const struct nft_traceinfo *i
 	return last->chain;
 }
 
-void nft_trace_notify(struct nft_traceinfo *info)
+void nft_trace_notify(const struct nft_pktinfo *pkt,
+		      struct nft_traceinfo *info)
 {
-	const struct nft_pktinfo *pkt = info->pkt;
 	const struct nft_chain *chain;
 	struct nlmsghdr *nlh;
 	struct sk_buff *skb;
@@ -305,7 +305,6 @@ void nft_trace_init(struct nft_traceinfo *info, const struct nft_pktinfo *pkt,
 	info->trace = true;
 	info->nf_trace = pkt->skb->nf_trace;
 	info->packet_dumped = false;
-	info->pkt = pkt;
 	info->verdict = verdict;
 
 	net_get_random_once(&trace_key, sizeof(trace_key));