diff --git a/crypto/rsa.c b/crypto/rsa.c
index 4c280b6..b067f3a 100644
--- a/crypto/rsa.c
+++ b/crypto/rsa.c
@@ -337,11 +337,11 @@ static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 	return -ENOMEM;
 }
 
-static int rsa_max_size(struct crypto_akcipher *tfm)
+static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
 {
 	struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
 
-	return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
+	return mpi_get_size(pkey->n);
 }
 
 static void rsa_exit_tfm(struct crypto_akcipher *tfm)