The variable is only used in an #ifdef, causing a harmless warning:
net/netfilter/nft_socket.c: In function 'nft_socket_init':
net/netfilter/nft_socket.c:137:27: error: unused variable 'level' [-Werror=unused-variable]
  137 |         unsigned int len, level;
      |                           ^~~~~
Move it into the same #ifdef block.
Fixes: e0bb96db96f8 ("netfilter: nft_socket: add support for cgroupsv2")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
                           const struct nlattr * const tb[])
 {
        struct nft_socket *priv = nft_expr_priv(expr);
-       unsigned int len, level;
+       unsigned int len;
 
        if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY])
                return -EINVAL;
                len = sizeof(u32);
                break;
 #ifdef CONFIG_CGROUPS
-       case NFT_SOCKET_CGROUPV2:
+       case NFT_SOCKET_CGROUPV2: {
+               unsigned int level;
+
                if (!tb[NFTA_SOCKET_LEVEL])
                        return -EINVAL;
 
                priv->level = level;
                len = sizeof(u64);
                break;
+       }
 #endif
        default:
                return -EOPNOTSUPP;