Re: [PATCH v4 04/10] tpm: Get rid of module locking

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Mon, Feb 29, 2016 at 10:35:50PM +0200, Jarkko Sakkinen wrote:
> On Mon, Feb 29, 2016 at 12:29:50PM -0500, Stefan Berger wrote:
> > Now that the tpm core has strong locking around 'ops' it is possible
> > to remove a TPM driver, module and all, even while user space still
> > has things like /dev/tpmX open. For consistency and simplicity, drop
> > the module locking entirely.
> 
> I don't understand why the user visible behavior of /dev/tpmX should
> be changed if there are no life and death reasons to do it. Do you
> think that this patch is absolutely crucial for the feature
> implemented?

Stefan is addressing it here because once NULL is a legal parent for
registration the chip->dev.parent->driver->owner expression becomes
useless for module locking.

If we want to keep module locking then Stefen has to add an 'owner'
field to tpm_class_ops and update all drivers. The ops->owner would
be used for the module locking instead of driver->owner

Jason

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