linux-kernel - Re: [PATCH] tpm: tpm_try_transmit() ignore value of go_to

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Message-ID: <20181016054155.GA18664@ziepe.ca>
Date:   Mon, 15 Oct 2018 23:41:55 -0600
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Tomas Winkler <tomas.winkler@...el.com>
Cc:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Nayna Jain <nayna@...ux.vnet.ibm.com>,
        Alexander Usyskin <alexander.usyskin@...el.com>,
        Tadeusz Struk <tadeusz.struk@...el.com>,
        linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tpm: tpm_try_transmit() ignore value of go_to_idle()

On Mon, Oct 15, 2018 at 02:14:34PM +0300, Tomas Winkler wrote:
> Ignore the return value of go_to_idle() in tpm_try_transmit().
> Once it may shadow the return value of actual tpm operation,
> second the consequent command will fail as well and the error
> will be caought anyway.
> Last fix wrong goto, that jumped back instead of forward.
> 
> Fixes: 627448e85c76 ("tpm: separate cmd_ready/go_idle from runtime_pm")
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
>  drivers/char/tpm/tpm-interface.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 129f640424b7..f69c711bf74a 100644
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -547,9 +547,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
>  		dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
>  
>  out:
> -	rc = tpm_go_idle(chip, flags);
> -	if (rc)
> -		goto out;
> +	(void)tpm_go_idle(chip, flags);

We don't really use this style in the kernel, AFAIK.

Jason