Re: [PATCH v4 1/2] tpm: Refactor tpm_transmit pulling out tpm_transfer function

[Stefan Berger]

On 05/10/2017 07:54 PM, Stefan Berger wrote:
> Refactor tpm_transmit and pull out code sending the command
> and receiving the response and put this into tpm_transfer.
>
> Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx>
> ---
>   drivers/char/tpm/tpm-interface.c | 121 +++++++++++++++++++++++----------------
>   1 file changed, 73 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 158c1db..263b6d1 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -370,67 +370,29 @@ static bool tpm_validate_command(struct tpm_chip *chip,
>   }
>
>   /**
> - * tmp_transmit - Internal kernel interface to transmit TPM commands.
> + * tmp_transfer - Send a TPM command to the TPM and receive response
>    *
>    * @chip: TPM chip to use
>    * @buf: TPM command buffer
> + * @count: size of the TPM command
>    * @bufsiz: length of the TPM command buffer
> - * @flags: tpm transmit flags - bitmap
>    *
>    * Return:
> - *     0 when the operation is successful.
> + *     >0 when the operation is successful; returns response length
>    *     A negative number for system errors (errno).
>    */
> -ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> -		     u8 *buf, size_t bufsiz, unsigned int flags)
> +ssize_t tpm_transfer(struct tpm_chip *chip, u8 *buf, u32 count, size_t bufsiz)
>   {
> -	struct tpm_output_header *header = (void *)buf;
>   	int rc;
> +	struct tpm_output_header *header = (void *)buf;
> +	u32 ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
>   	ssize_t len = 0;
> -	u32 count, ordinal;
>   	unsigned long stop;
> -	bool need_locality;
> -
> -	if (!tpm_validate_command(chip, space, buf, bufsiz))
> -		return -EINVAL;
> -
> -	if (bufsiz > TPM_BUFSIZE)
> -		bufsiz = TPM_BUFSIZE;
> -
> -	count = be32_to_cpu(*((__be32 *) (buf + 2)));
> -	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
> -	if (count == 0)
> -		return -ENODATA;
> -	if (count > bufsiz) {
> -		dev_err(&chip->dev,
> -			"invalid count value %x %zx\n", count, bufsiz);
> -		return -E2BIG;
> -	}
> -
> -	if (!(flags & TPM_TRANSMIT_UNLOCKED))
> -		mutex_lock(&chip->tpm_mutex);
> -
> -	if (chip->dev.parent)
> -		pm_runtime_get_sync(chip->dev.parent);
> -
> -	/* Store the decision as chip->locality will be changed. */
> -	need_locality = chip->locality == -1;
> -
> -	if (need_locality && chip->ops->request_locality)  {
> -		rc = chip->ops->request_locality(chip, 0);
> -		if (rc < 0)
> -			goto out_no_locality;
> -		chip->locality = rc;
> -	}
> -
> -	rc = tpm2_prepare_space(chip, space, ordinal, buf);
> -	if (rc)
> -		goto out;
>
>   	rc = chip->ops->send(chip, (u8 *) buf, count);
>   	if (rc < 0) {
>   		dev_err(&chip->dev,
> -			"tpm_transmit: tpm_send: error %d\n", rc);
> +			"tpm_transfer: tpm_send: error %d\n", rc);
>   		goto out;
>   	}
>
> @@ -467,18 +429,81 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
missing here: rc = 0;

>   	if (len < 0) {
>   		rc = len;
>   		dev_err(&chip->dev,
> -			"tpm_transmit: tpm_recv: error %d\n", rc);
> +			"tpm_transfer: tpm_recv: error %d\n", rc);
>   		goto out;
>   	} else if (len < TPM_HEADER_SIZE) {
>   		rc = -EFAULT;
>   		goto out;
>   	}
>
> -	if (len != be32_to_cpu(header->length)) {
> +	if (len != be32_to_cpu(header->length))
>   		rc = -EFAULT;
> -		goto out;
> +
> +out:
> +	return rc ? rc : len;
> +}
> +EXPORT_SYMBOL_GPL(tpm_transfer);
> +
> +/**
> + * tmp_transmit - Internal kernel interface to transmit TPM commands.
> + *
> + * @chip: TPM chip to use
> + * @buf: TPM command buffer
> + * @bufsiz: length of the TPM command buffer
> + * @flags: tpm transmit flags - bitmap
> + *
> + * Return:
> + *     0 when the operation is successful.
> + *     A negative number for system errors (errno).
> + */
> +ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> +		     u8 *buf, size_t bufsiz, unsigned int flags)
> +{
> +	int rc;
> +	ssize_t len = 0;
> +	u32 count, ordinal;
> +	bool need_locality;
> +
> +	if (!tpm_validate_command(chip, space, buf, bufsiz))
> +		return -EINVAL;
> +
> +	if (bufsiz > TPM_BUFSIZE)
> +		bufsiz = TPM_BUFSIZE;
> +
> +	count = be32_to_cpu(*((__be32 *) (buf + 2)));
> +	ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
> +	if (count == 0)
> +		return -ENODATA;
> +	if (count > bufsiz) {
> +		dev_err(&chip->dev,
> +			"invalid count value %x %zx\n", count, bufsiz);
> +		return -E2BIG;
> +	}
> +
> +	if (!(flags & TPM_TRANSMIT_UNLOCKED))
> +		mutex_lock(&chip->tpm_mutex);
> +
> +	if (chip->dev.parent)
> +		pm_runtime_get_sync(chip->dev.parent);
> +
> +	/* Store the decision as chip->locality will be changed. */
> +	need_locality = chip->locality == -1;
> +
> +	if (need_locality && chip->ops->request_locality)  {
> +		rc = chip->ops->request_locality(chip, 0);
> +		if (rc < 0)
> +			goto out_no_locality;
> +		chip->locality = rc;
>   	}
>
> +	rc = tpm2_prepare_space(chip, space, ordinal, buf);
> +	if (rc)
> +		goto out;
> +
> +	len = tpm_transfer(chip, buf, count, bufsiz);
> +	if (len < 0)
> +		goto out;
> +
>   	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
>
>   out: