Re: [tpmdd-devel] [PATCH v2 2/7] tpm: two-phase chip management functions

On Tue, Oct 07, 2014 at 04:34:42PM -0600, Jason Gunthorpe wrote:

On Wed, Oct 08, 2014 at 01:28:14AM +0300, Jarkko Sakkinen wrote:

quoted

quoted

quoted

@@ -714,15 +709,10 @@ static int tpm_tis_i2c_remove(struct i2c_client *client)
 	struct tpm_chip *chip = tpm_dev.chip;
 	release_locality(chip, chip->vendor.locality, 1);
 
-	/* close file handles */
-	tpm_dev_vendor_release(chip);
-
 	/* remove hardware */
 	tpm_remove_hardware(chip->dev);

Wrong ordering here, tpm_remove_hardware should always be first -
drivers should not tear down internal state before calling it, so
release_locality should be second.

Noting that since we use devm the kfree will not happen until
remove returns, so the chip pointer is still valid.

Should I fix this ordering? I was thinking to focus putting proper
patterns in place only in tpm_tis and tpm_crb because they are the
that I'm able to test easily and then they can work as guideline for
other drivers.

I think since this patch is already touching this function there is
no reason not to make it be correct (especially since it was noticed)

The rest can wait till we globally replace tpm_remove_hardware with
tpm_unregister - at that time the ordering can be audited and
checked.

Then the drivers will be clean and the core can finally be fixed.

This makes sense. I'll also document this. And I decided to completely
wipe old tpm_register/remove_hardware() completely from v3 because they
only cause confusion.

I pushed patch that should implement fix for the ordering into tpm2-v2
branch:

https://github.com/jsakkine/linux-tpm2/commit/63ab650fa6f8dddd95100869e50275801d7d9360

Jason

/Jarkko