Re: [PATCH v2 03/11] fscrypt: split and rename setup_per_mode_enc_key()

[Eric Biggers <ebiggers@kernel.org>]

On Mon, Apr 10, 2023 at 03:39:56PM -0400, Sweet Tea Dorminy wrote:
> @@ -231,14 +221,39 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
>  	memzero_explicit(mode_key, mode->keysize);
>  	if (err)
>  		goto out_unlock;
> -done_unlock:
> -	ci->ci_enc_key = *prep_key;
> -	err = 0;
> +
>  out_unlock:

The 'if (err)' block above is no longer needed.

> +static int find_mode_prepared_key(struct fscrypt_info *ci,
> +				  struct fscrypt_master_key *mk,
> +				  struct fscrypt_prepared_key *keys,
> +				  u8 hkdf_context, bool include_fs_uuid)
> +{
> +	struct fscrypt_mode *mode = ci->ci_mode;
> +	const u8 mode_num = mode - fscrypt_modes;
> +	struct fscrypt_prepared_key *prep_key;
> +	int err;
> +
> +	if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX))
> +		return -EINVAL;
> +
> +	prep_key = &keys[mode_num];
> +	if (fscrypt_is_key_prepared(prep_key, ci)) {
> +		ci->ci_enc_key = *prep_key;
> +		return 0;
> +	}
> +	err = setup_new_mode_prepared_key(mk, prep_key, ci, hkdf_context,
> +					  include_fs_uuid);
> +	if (err)
> +		return err;
> +
> +	ci->ci_enc_key = *prep_key;
> +	return 0;
> +}

It actually should be find_or_create_mode_prepared_key(), right?  It's confusing
to have a function that just says "find" actually create the thing it is looking
for.

But, with how long these function names would get, maybe we should just stick
with setup_mode_prepared_key()?  Note that it has the same semantics (find or
create) as fscrypt_setup_ino_hash_key(), which this patchset doesn't change.

- Eric