netfilter: nf_tables: Simplify chain netdev notifier

With conditional chain deletion gone, callback code simplifies: Instead
of filling an nft_ctx object, just pass basechain to the per-chain
function. Also plain list_for_each_entry() is safe now.

Signed-off-by: Phil Sutter <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>

Author: Phil Sutter

net/netfilter/nft_chain_filter.c

@@ -319,17 +319,16 @@ static const struct nft_chain_type nft_chain_filter_netdev = {
 };
 
 static void nft_netdev_event(unsigned long event, struct net_device *dev,
-			     struct nft_ctx *ctx)
+			     struct nft_base_chain *basechain)
 {
-	struct nft_base_chain *basechain = nft_base_chain(ctx->chain);
 	struct nft_hook *hook;
 
 	list_for_each_entry(hook, &basechain->hook_list, list) {
 		if (hook->ops.dev != dev)
 			continue;
 
-		if (!(ctx->chain->table->flags & NFT_TABLE_F_DORMANT))
-			nf_unregister_net_hook(ctx->net, &hook->ops);
+		if (!(basechain->chain.table->flags & NFT_TABLE_F_DORMANT))
+			nf_unregister_net_hook(dev_net(dev), &hook->ops);
 
 		list_del_rcu(&hook->list);
 		kfree_rcu(hook, rcu);
@@ -343,25 +342,20 @@ static int nf_tables_netdev_event(struct notifier_block *this,
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct nft_base_chain *basechain;
 	struct nftables_pernet *nft_net;
-	struct nft_chain *chain, *nr;
+	struct nft_chain *chain;
 	struct nft_table *table;
-	struct nft_ctx ctx = {
-		.net	= dev_net(dev),
-	};
 
 	if (event != NETDEV_UNREGISTER)
 		return NOTIFY_DONE;
 
-	nft_net = nft_pernet(ctx.net);
+	nft_net = nft_pernet(dev_net(dev));
 	mutex_lock(&nft_net->commit_mutex);
 	list_for_each_entry(table, &nft_net->tables, list) {
 		if (table->family != NFPROTO_NETDEV &&
 		    table->family != NFPROTO_INET)
 			continue;
 
-		ctx.family = table->family;
-		ctx.table = table;
-		list_for_each_entry_safe(chain, nr, &table->chains, list) {
+		list_for_each_entry(chain, &table->chains, list) {
 			if (!nft_is_base_chain(chain))
 				continue;
 
@@ -370,8 +364,7 @@ static int nf_tables_netdev_event(struct notifier_block *this,
 			    basechain->ops.hooknum != NF_INET_INGRESS)
 				continue;
 
-			ctx.chain = chain;
-			nft_netdev_event(event, dev, &ctx);
+			nft_netdev_event(event, dev, basechain);
 		}
 	}
 	mutex_unlock(&nft_net->commit_mutex);