[PATCH] tpm: Create cleanup class for tpm_buf

[Jason Gunthorpe]

On Thu, Jun 26, 2025 at 12:37:56AM +0300, Jarkko Sakkinen wrote:
> @@ -323,7 +323,7 @@ unsigned long tpm1_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
>   */
>  static int tpm1_startup(struct tpm_chip *chip)
>  {
> -	struct tpm_buf buf;
> +	CLASS(tpm_buf, buf)();
>  	int rc;
>  
>  	dev_info(&chip->dev, "starting up the TPM manually\n");
> @@ -335,7 +335,6 @@ static int tpm1_startup(struct tpm_chip *chip)
>  	tpm_buf_append_u16(&buf, TPM_ST_CLEAR);
>  
>  	rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
> -	tpm_buf_destroy(&buf);
>  	return rc;
>  }

So, Linus has spoken negatively about just converting existing code to
use cleanup.h, fearful it would introduce more bugs.

I would certainly split this into more patches, and it would be nice
if something mechanical like coccinelle could do the change.

At least I would add the class and drop the tpm_buf_destroy() as one
patch, and another would be to cleanup any empty gotos.

Also, I think the style guide for cleanup.h is to not use the
variable block, so it should be more like:

CLASS(tpm_buf, buf)();
if (!tpm_buf)
   return -ENOMEM;

AFAICT, but that seems to be some kind of tribal knowledge.

Jason