linux-kernel - Re: [PATCH 2/5] tpm: migrate tpm2_shutdown() to use struct tpm

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Message-ID: <20180228202540.GA19007@ziepe.ca>
Date:   Wed, 28 Feb 2018 13:25:40 -0700
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, keyrings@...r.kernel.org,
        Peter Huewe <peterhuewe@....de>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/5] tpm: migrate tpm2_shutdown() to use struct tpm_buf

On Wed, Feb 28, 2018 at 09:58:15PM +0200, Jarkko Sakkinen wrote:
> In order to make struct tpm_buf the first class object for constructing TPM
> commands, migrate tpm2_shutdown() to use it. In addition, removed the klog
> entry when tpm_transmit_cmd() fails because tpm_tansmit_cmd() already
> prints an error message.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
>  drivers/char/tpm/tpm2-cmd.c | 41 +++++++++++++----------------------------
>  1 file changed, 13 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 6eeff3a60003..5f92141b1e16 100644
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -27,10 +27,6 @@ enum tpm2_session_attributes {
>  	TPM2_SA_CONTINUE_SESSION	= BIT(0),
>  };
>  
> -struct tpm2_startup_in {
> -	__be16	startup_type;
> -} __packed;
> -
>  struct tpm2_get_tpm_pt_in {
>  	__be32	cap_id;
>  	__be32	property_id;
> @@ -55,7 +51,6 @@ struct tpm2_get_random_out {
>  } __packed;
>  
>  union tpm2_cmd_params {
> -	struct	tpm2_startup_in		startup_in;
>  	struct	tpm2_get_tpm_pt_in	get_tpm_pt_in;
>  	struct	tpm2_get_tpm_pt_out	get_tpm_pt_out;
>  	struct	tpm2_get_random_in	getrandom_in;
> @@ -760,40 +755,30 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
>  }
>  EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);
>  
> -#define TPM2_SHUTDOWN_IN_SIZE \
> -	(sizeof(struct tpm_input_header) + \
> -	 sizeof(struct tpm2_startup_in))
> -
> -static const struct tpm_input_header tpm2_shutdown_header = {
> -	.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
> -	.length = cpu_to_be32(TPM2_SHUTDOWN_IN_SIZE),
> -	.ordinal = cpu_to_be32(TPM2_CC_SHUTDOWN)
> -};
> -
>  /**
>   * tpm2_shutdown() - send shutdown command to the TPM chip
>   *
> + * In places where shutdown command is sent there's no much we can do except
> + * print the error code on a system failure.
> + *
>   * @chip:		TPM chip to use.
>   * @shutdown_type:	shutdown type. The value is either
>   *			TPM_SU_CLEAR or TPM_SU_STATE.
>   */
>  void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
>  {
> -	struct tpm2_cmd cmd;
> +	struct tpm_buf buf;
>  	int rc;
>  
> -	cmd.header.in = tpm2_shutdown_header;
> -	cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
> -
> -	rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
> -			      "stopping the TPM");
> -
> -	/* In places where shutdown command is sent there's no much we can do
> -	 * except print the error code on a system failure.
> -	 */
> -	if (rc < 0 && rc != -EPIPE)
> -		dev_warn(&chip->dev, "transmit returned %d while stopping the TPM",
> -			 rc);
> +	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SHUTDOWN);
> +	if (rc) {
> +		dev_err(&chip->dev, "%s: out of memory", __func__);

Don't print for out of memory. The kernel already makes lots of
prints for you. Same comment everywhere.

Jason