linux-kernel - Re: [PATCH] tpm: st33zp24: remove redundant null check on chip

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Message-ID: <4ea103c15998af56813fb870ac9a27a34a694f49.camel@linux.intel.com>
Date:   Mon, 09 Apr 2018 14:11:08 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Colin King <colin.king@...onical.com>,
        Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-integrity@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tpm: st33zp24: remove redundant null check on chip

On Fri, 2018-04-06 at 17:21 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> Currently chip is being dereferenced by the call to dev_get_drvdata
> before it is being null checked, however, chip can never be null, so
> this check is misleading and redundant. Remove it.
> 
> Detected by CoverityScan, CID#1357806 ("Dereference before null check")
> 
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> 
> ---
> 
> V2: don't check for null, just remove redundant null check,
>     thanks to Jason Gunthorpe for spotting that.
> 
> ---
>  drivers/char/tpm/st33zp24/st33zp24.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/st33zp24/st33zp24.c
> b/drivers/char/tpm/st33zp24/st33zp24.c
> index f95b9c75175b..abd675bec88c 100644
> --- a/drivers/char/tpm/st33zp24/st33zp24.c
> +++ b/drivers/char/tpm/st33zp24/st33zp24.c
> @@ -373,8 +373,6 @@ static int st33zp24_send(struct tpm_chip *chip, unsigned
> char *buf,
>  	int ret;
>  	u8 data;
>  
> -	if (!chip)
> -		return -EBUSY;
>  	if (len < TPM_HEADER_SIZE)
>  		return -EBUSY;
>  

Reviewed-by: Jarkko Sakkinen <jarkkko.sakkinen@...ux.intel.com>

/Jarkko