tls: don't override sk_write_space if tls_set_sw_offload fails.

commit ee181e52 upstream.

If we fail to enable tls in the kernel we shouldn't override
the sk_write_space callback

Fixes: 3c4d7559 ('tls: kernel TLS support')
Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

net/tls/tls_main.c

@@ -429,9 +429,6 @@ static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval,
 		goto err_crypto_info;
 	}
 
-	ctx->sk_write_space = sk->sk_write_space;
-	sk->sk_write_space = tls_write_space;
-
 	/* currently SW is default, we will have ethtool in future */
 	rc = tls_set_sw_offload(sk, ctx);
 	tx_conf = TLS_SW_TX;
@@ -440,6 +437,8 @@ static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval,
 
 	ctx->tx_conf = tx_conf;
 	update_sk_prot(sk, ctx);
+	ctx->sk_write_space = sk->sk_write_space;
+	sk->sk_write_space = tls_write_space;
 	goto out;
 
 err_crypto_info: