Re: [tpmdd-devel] [PATCH] tpm: missing tpm_chip_put in tpm_get_random()

[Jason Gunthorpe <jgunthorpe@obsidianresearch.com>]

On Fri, May 09, 2014 at 02:23:10PM +0300, Jarkko Sakkinen wrote:
> Regression in 41ab999c. Call to tpm_chip_put is missing. This
> will cause TPM device driver not to unload if tmp_get_random()
> is called.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

>  drivers/char/tpm/tpm-interface.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 62e10fd..4ea4d52 100644
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -991,13 +991,13 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
>  	int err, total = 0, retries = 5;
>  	u8 *dest = out;
>  
> +	if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
> +		return -EINVAL;
> +
>  	chip = tpm_chip_find_get(chip_num);
>  	if (chip == NULL)
>  		return -ENODEV;
>  
> -	if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
> -		return -EINVAL;
> -
>  	do {
>  		tpm_cmd.header.in = tpm_getrandom_header;
>  		tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes);
> @@ -1016,6 +1016,7 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
>  		num_bytes -= recd;
>  	} while (retries-- && total < max);
>  
> +	tpm_chip_put(chip);
>  	return total ? total : -EIO;
>  }
>  EXPORT_SYMBOL_GPL(tpm_get_random);