linux-kernel - Re: [PATCH v8 2/3] tpm_crb_ffa:Introduce memzero macro to replace memset

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Message-ID: <aGWvtzhs5ksKgaYo@kernel.org>
Date: Thu, 3 Jul 2025 01:16:23 +0300
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Prachotan Bathi <prachotan.bathi@....com>
Cc: Peter Huewe <peterhuewe@....de>, Jason Gunthorpe <jgg@...pe.ca>,
	Stuart Yoder <stuart.yoder@....com>,
	linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 2/3] tpm_crb_ffa:Introduce memzero macro to replace
 memset

On Thu, Jun 26, 2025 at 01:45:20PM -0500, Prachotan Bathi wrote:
> Add a memzero macro to simplify and standardize zeroing
> FF-A data args, replacing direct uses of memset for
> improved readability and maintainability.
> 
> Signed-off-by: Prachotan Bathi <prachotan.bathi@....com>
> ---
>  drivers/char/tpm/tpm_crb_ffa.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
> index 089d1e54bb46..397cc3b0a478 100644
> --- a/drivers/char/tpm/tpm_crb_ffa.c
> +++ b/drivers/char/tpm/tpm_crb_ffa.c
> @@ -12,6 +12,8 @@
>  #include <linux/arm_ffa.h>
>  #include "tpm_crb_ffa.h"
>  
> +#define memzero(s, n) memset((s), 0, (n))
> +
>  /* TPM service function status codes */
>  #define CRB_FFA_OK			0x05000001
>  #define CRB_FFA_OK_RESULTS_RETURNED	0x05000002
> @@ -192,7 +194,7 @@ static int __tpm_crb_ffa_send_receive(unsigned long func_id,
>  	msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops;
>  
>  	if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) {
> -		memset(&tpm_crb_ffa->direct_msg_data2, 0x00,
> +		memzero(&tpm_crb_ffa->direct_msg_data2,
>  		       sizeof(struct ffa_send_direct_data2));
>  
>  		tpm_crb_ffa->direct_msg_data2.data[0] = func_id;
> @@ -205,7 +207,7 @@ static int __tpm_crb_ffa_send_receive(unsigned long func_id,
>  		if (!ret)
>  			ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data2.data[0]);
>  	} else {
> -		memset(&tpm_crb_ffa->direct_msg_data, 0x00,
> +		memzero(&tpm_crb_ffa->direct_msg_data,
>  		       sizeof(struct ffa_send_direct_data));
>  
>  		tpm_crb_ffa->direct_msg_data.data1 = func_id;
> -- 
> 2.43.0
> 

It adds a ross-reference to the source code, meaning that you have to
jump back and forth in the source code just to see that there is a
function that wraps up a single memset() call.

How does that map to "readability"?

BR, Jarkko