netfilter: nf_tables: pass nft_chain to destroy function, not nft_ctx

It would be better to not store nft_ctx inside nft_trans object,
the netlink ctx strucutre is huge and most of its information is
never needed in places that use trans->ctx.

Avoid/reduce its usage if possible, no runtime behaviour change
intended.

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

include/net/netfilter/nf_tables.h

@@ -1171,7 +1171,7 @@ static inline bool nft_chain_is_bound(struct nft_chain *chain)
 
 int nft_chain_add(struct nft_table *table, struct nft_chain *chain);
 void nft_chain_del(struct nft_chain *chain);
-void nf_tables_chain_destroy(struct nft_ctx *ctx);
+void nf_tables_chain_destroy(struct nft_chain *chain);
 
 struct nft_stats {
 	u64			bytes;

net/netfilter/nf_tables_api.c

@@ -2118,9 +2118,9 @@ static void nf_tables_chain_free_chain_rules(struct nft_chain *chain)
 	kvfree(chain->blob_next);
 }
 
-void nf_tables_chain_destroy(struct nft_ctx *ctx)
+void nf_tables_chain_destroy(struct nft_chain *chain)
 {
-	struct nft_chain *chain = ctx->chain;
+	const struct nft_table *table = chain->table;
 	struct nft_hook *hook, *next;
 
 	if (WARN_ON(chain->use > 0))
@@ -2132,7 +2132,7 @@ void nf_tables_chain_destroy(struct nft_ctx *ctx)
 	if (nft_is_base_chain(chain)) {
 		struct nft_base_chain *basechain = nft_base_chain(chain);
 
-		if (nft_base_chain_netdev(ctx->family, basechain->ops.hooknum)) {
+		if (nft_base_chain_netdev(table->family, basechain->ops.hooknum)) {
 			list_for_each_entry_safe(hook, next,
 						 &basechain->hook_list, list) {
 				list_del_rcu(&hook->list);
@@ -2621,7 +2621,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
 err_trans:
 	nft_use_dec_restore(&table->use);
 err_destroy_chain:
-	nf_tables_chain_destroy(ctx);
+	nf_tables_chain_destroy(chain);
 
 	return err;
 }
@@ -9532,7 +9532,7 @@ static void nft_commit_release(struct nft_trans *trans)
 		if (nft_trans_chain_update(trans))
 			nft_hooks_destroy(&nft_trans_chain_hooks(trans));
 		else
-			nf_tables_chain_destroy(&trans->ctx);
+			nf_tables_chain_destroy(nft_trans_chain(trans));
 		break;
 	case NFT_MSG_DELRULE:
 	case NFT_MSG_DESTROYRULE:
@@ -10524,7 +10524,7 @@ static void nf_tables_abort_release(struct nft_trans *trans)
 		if (nft_trans_chain_update(trans))
 			nft_hooks_destroy(&nft_trans_chain_hooks(trans));
 		else
-			nf_tables_chain_destroy(&trans->ctx);
+			nf_tables_chain_destroy(nft_trans_chain(trans));
 		break;
 	case NFT_MSG_NEWRULE:
 		nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans));
@@ -11411,7 +11411,7 @@ int __nft_release_basechain(struct nft_ctx *ctx)
 	}
 	nft_chain_del(ctx->chain);
 	nft_use_dec(&ctx->table->use);
-	nf_tables_chain_destroy(ctx);
+	nf_tables_chain_destroy(ctx->chain);
 
 	return 0;
 }
@@ -11486,10 +11486,9 @@ static void __nft_release_table(struct net *net, struct nft_table *table)
 		nft_obj_destroy(&ctx, obj);
 	}
 	list_for_each_entry_safe(chain, nc, &table->chains, list) {
-		ctx.chain = chain;
 		nft_chain_del(chain);
 		nft_use_dec(&table->use);
-		nf_tables_chain_destroy(&ctx);
+		nf_tables_chain_destroy(chain);
 	}
 	nf_tables_table_destroy(&ctx);
 }

net/netfilter/nft_immediate.c

@@ -221,7 +221,7 @@ static void nft_immediate_destroy(const struct nft_ctx *ctx,
 			list_del(&rule->list);
 			nf_tables_rule_destroy(&chain_ctx, rule);
 		}
-		nf_tables_chain_destroy(&chain_ctx);
+		nf_tables_chain_destroy(chain);
 		break;
 	default:
 		break;