Re: [PATCH 02/10] nvme: add nvme_auth_generate_psk()

[Christoph Hellwig <hch@lst.de>]

> + * Generate a PSK for TLS as specified in NVMe base specification, section 8.13.5.9:

Please fix your comment to stay in 80 characters.  The line wrapping
here makes the text almost unreadable.

> +int nvme_auth_generate_psk(u8 hmac_id, u8 *skey, size_t skey_len,
> +		u8 *c1, u8 *c2, size_t hash_len, u8 **ret_psk,size_t *ret_len)

Missing whitespace before the last size_t.

> +{
> +	struct crypto_shash *tfm;
> +	struct shash_desc *shash;
> +	u8 *psk;
> +	const char *hmac_name;
> +	int ret, psk_len;
> +
> +	if (!c1 || !c2) {
> +		pr_warn("%s: invalid parameter\n", __func__);
> +		return -EINVAL;
> +	}

No a very useful error message.  Given that this is a violation of
the API contract either a WARN_ON_ONCE or just letting the crypto
algorithm fail should be fine.

> +	tfm = crypto_alloc_shash(hmac_name, 0, 0);
> +	if (IS_ERR(tfm))
> +		return PTR_ERR(tfm);
> +
> +	psk_len = crypto_shash_digestsize(tfm);
> +	psk = kzalloc(psk_len, GFP_KERNEL);
> +	if (!psk) {
> +		ret = -ENOMEM;
> +		goto out_free_tfm;
> +	}
> +
> +	shash = kmalloc(sizeof(struct shash_desc) +
> +			crypto_shash_descsize(tfm),
> +			GFP_KERNEL);
> +	if (!shash) {
> +		ret = -ENOMEM;
> +		goto out_free_psk;
> +	}

Is there a good reason this can't use SHASH_DESC_ON_STACK()?