linux-kernel - Re: [PATCH 15/44] drivers/char/tpm: use min() instead of min

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Message-ID: <aSDHihcWOHGLAjTb@kernel.org>
Date: Fri, 21 Nov 2025 22:11:54 +0200
From: Jarkko Sakkinen <jarkko@...nel.org>
To: david.laight.linux@...il.com
Cc: linux-kernel@...r.kernel.org, linux-integrity@...r.kernel.org,
	Peter Huewe <peterhuewe@....de>
Subject: Re: [PATCH 15/44] drivers/char/tpm: use min() instead of min_t()

On Wed, Nov 19, 2025 at 10:41:11PM +0000, david.laight.linux@...il.com wrote:
> From: David Laight <david.laight.linux@...il.com>
> 
> min_t(int, a, b) casts an 'long' to 'int'.
> Use min(a, b) instead as it promotes any 'int' to 'long'
> and so cannot discard significant bits.
> 
> In this case the 'long' value is small enough that the result is ok.
> 
> Detected by an extra check added to min_t().
> 
> Signed-off-by: David Laight <david.laight.linux@...il.com>
> ---
>  drivers/char/tpm/tpm1-cmd.c     | 2 +-
>  drivers/char/tpm/tpm_tis_core.c | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
> index cf64c7385105..11088bda4e68 100644
> --- a/drivers/char/tpm/tpm1-cmd.c
> +++ b/drivers/char/tpm/tpm1-cmd.c
> @@ -530,7 +530,7 @@ struct tpm1_get_random_out {
>  int tpm1_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
>  {
>  	struct tpm1_get_random_out *out;
> -	u32 num_bytes =  min_t(u32, max, TPM_MAX_RNG_DATA);
> +	u32 num_bytes =  min(max, TPM_MAX_RNG_DATA);
>  	struct tpm_buf buf;
>  	u32 total = 0;
>  	int retries = 5;
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 8954a8660ffc..2676e3a241b5 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -310,7 +310,7 @@ static int get_burstcount(struct tpm_chip *chip)
>  	return -EBUSY;
>  }
>  
> -static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
> +static int recv_data(struct tpm_chip *chip, u8 *buf, u32 count)
>  {
>  	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>  	int size = 0, burstcnt, rc;
> @@ -453,7 +453,7 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
>  			rc = burstcnt;
>  			goto out_err;
>  		}
> -		burstcnt = min_t(int, burstcnt, len - count - 1);
> +		burstcnt = min(burstcnt, len - count - 1);
>  		rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
>  					 burstcnt, buf + count);
>  		if (rc < 0)
> -- 
> 2.39.5
> 

Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>

BR, Jarkko