Re: [tpmdd-devel] [PATCH] tpm: remove chip_num parameter from in-kernel API

[Jason Gunthorpe]

On Tue, Oct 24, 2017 at 09:37:33PM +0530, PrasannaKumar Muralidharan wrote:
> Hi Jason,
> 
> On 24 October 2017 at 21:25, Jason Gunthorpe
> <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Tue, Oct 24, 2017 at 09:21:15PM +0530, PrasannaKumar Muralidharan wrote:
> >
> >> Please check the RFC [1]. It does use chip id. The rfc has issues and
> >> has to be fixed but still there could be users of the API.
> >>
> >> 1. https://www.spinics.net/lists/linux-crypto/msg28282.html
> >
> > That patch isn't safe at all. You need to store a kref to th chip in
> > the hwrng, not parse a string.
> 
> The drivers/char/hw_random/tpm-rng.c module does not store the chip
> reference so I guess the usage is safe.

It is using the default TPM, it is always safe to use the default tpm.

> The RFC is just a sample use case of the API.

Well, a wrong example not to be emulated, and I think, further shows
how Jarkko's direction is the right one.

Jason