On Thu, Jun 26, 2025 at 11:49:15AM -0300, Jason Gunthorpe wrote:

On Thu, Jun 26, 2025 at 12:37:56AM +0300, Jarkko Sakkinen wrote:

quoted

@@ -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 did not do this for the sake of conversion. It's just that tpm_buf is
a pretty good fit for such construct, as it is always in function scope
and always heap allocated.

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

I took this a bit in further:

https://lore.kernel.org/linux-integrity/aF2NNHilFfZwBoxA@kernel.org/T/#t (local)

I did that few dozen times while developing this, running always at
minimum:

1. https://codeberg.org/jarkko/linux-tpmdd-test/src/branch/main/board/pc_x86_64/test_tpm2_kselftest.exp.in
2. https://codeberg.org/jarkko/linux-tpmdd-test/src/branch/main/board/pc_x86_64/test_tpm2_trusted.exp.in

A few times I run some ad-hoc tests too.

And despite 89% is mechanical work there was at least a dozen code
blocks where you need to understand the context too. So actually with
this careful manual work was not that bad idea in the end.

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.

This was improved in v2 :-) If you have some proposal how you'd
liked that version to be splitted, please give feedback.

Jason

BR, Jarkko