netfilter: nf_tables: add nft_trans_commit_list_add_elem helper

Add and use a wrapper to append trans_elem structures to the
transaction log.

Unlike the existing helper, pass a gfp_t to indicate if sleeping
is allowed.

This will be used by a followup patch to realloc nft_trans_elem
structures after they gain a flexible array member to reduce
number of such container structures on the transaction list.

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

Author: Florian Westphal

net/netfilter/nf_tables_api.c

@@ -421,6 +421,17 @@ static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *tr
 	}
 }
 
+static void nft_trans_commit_list_add_elem(struct net *net, struct nft_trans *trans,
+					   gfp_t gfp)
+{
+	WARN_ON_ONCE(trans->msg_type != NFT_MSG_NEWSETELEM &&
+		     trans->msg_type != NFT_MSG_DELSETELEM);
+
+	might_alloc(gfp);
+
+	nft_trans_commit_list_add_tail(net, trans);
+}
+
 static int nft_trans_table_add(struct nft_ctx *ctx, int msg_type)
 {
 	struct nft_trans *trans;
@@ -7205,7 +7216,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 					if (update_flags) {
 						nft_trans_elem_priv(trans) = elem_priv;
 						nft_trans_elem_update_flags(trans) = update_flags;
-						nft_trans_commit_list_add_tail(ctx->net, trans);
+						nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
 						goto err_elem_free;
 					}
 				}
@@ -7229,7 +7240,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
 	}
 
 	nft_trans_elem_priv(trans) = elem.priv;
-	nft_trans_commit_list_add_tail(ctx->net, trans);
+	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
 	return 0;
 
 err_set_full:
@@ -7446,7 +7457,7 @@ static int nft_del_setelem(struct nft_ctx *ctx, struct nft_set *set,
 	nft_setelem_data_deactivate(ctx->net, set, elem.priv);
 
 	nft_trans_elem_priv(trans) = elem.priv;
-	nft_trans_commit_list_add_tail(ctx->net, trans);
+	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
 	return 0;
 
 fail_ops:
@@ -7482,7 +7493,7 @@ static int nft_setelem_flush(const struct nft_ctx *ctx,
 	nft_setelem_data_deactivate(ctx->net, set, elem_priv);
 	nft_trans_elem_set(trans) = set;
 	nft_trans_elem_priv(trans) = elem_priv;
-	nft_trans_commit_list_add_tail(ctx->net, trans);
+	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_ATOMIC);
 
 	return 0;
 }
@@ -7499,7 +7510,7 @@ static int __nft_set_catchall_flush(const struct nft_ctx *ctx,
 
 	nft_setelem_data_deactivate(ctx->net, set, elem_priv);
 	nft_trans_elem_priv(trans) = elem_priv;
-	nft_trans_commit_list_add_tail(ctx->net, trans);
+	nft_trans_commit_list_add_elem(ctx->net, trans, GFP_KERNEL);
 
 	return 0;
 }