Hi Jason,

On 24 October 2017 at 23:16, Jason Gunthorpe
[off-list ref] wrote:

On Tue, Oct 24, 2017 at 09:44:30PM +0530, PrasannaKumar Muralidharan wrote:

quoted

I am wondering why it is wrong. Isn't the chip id valid till it is
unregistered? If so the rfc is correct. Please explain, may be I am
missing something.

The lifetime is a bit complicated, but the general rule in the kernel
for things like this it to use pointers, not ids, and certainly not
string ids.

For that patch it could just use container_of to get the chip..

Jason

hwrng requires a unique name for every device. In that patch
"tpm-rng-<chip_num>" is used. chip_num is nothing but dev->dev_num.
This way more than 1 tpm chip can be used as rng provider.
tpm_get_random uses chip_num as its parameter. This is why
chip->dev_num was used.

Is that reasoning correct?

Please feel free to correct me if I am wrong.

Thanks,
PrasannaKumar