Re: [tpmdd-devel] [PATCH v2 2/7] tpm: two-phase chip management functions
From: Jarkko Sakkinen
Date: Thu Oct 09 2014 - 05:07:59 EST
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:
> > > > @@ -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
> 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
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