Re: [PATCH v2] tpm: use struct tpm_chip for tpm_chip_find_get()

Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
Newsgroups net.sourceforge.lists.tpmdd-devel,org.kernel.vger.keyrings,org.kernel.vger.linux-crypto,org.kernel.vger.linux-integrity,org.kernel.vger.linux-kernel,org.kernel.vger.linux-security-module
Message-ID <[email protected]>
On Wed, Oct 25, 2017 at 10:07:46PM +0200, Jarkko Sakkinen wrote:

> The id has a nice feature that it is unique for one boot cycle you can
> even try to get a chip that has been deleted. It has the most stable
> properties in the long run.

It isn't unique, we can re-use ids them via idr_alloc(). We should
never use index inside the kernel.

> Address is a reusable identifier in one boot cycle.

It is invalid to pass in a chip for which the caller does not hold a
kref, so address is the safest argument.

Jason

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