Re: [PATCH v3 03/03]: hwrng: khwrngd derating per device

From: Andy Lutomirski
Date: Tue Apr 15 2014 - 12:54:28 EST


On Tue, Apr 15, 2014 at 1:51 AM, Torsten Duwe <duwe@xxxxxx> wrote:
> On Mon, Apr 14, 2014 at 09:41:10AM -0700, Andy Lutomirski wrote:
>> On Mon, Apr 14, 2014 at 9:06 AM, Torsten Duwe <duwe@xxxxxx> wrote:
>> >
>> > This patch introduces a derating factor to struct hwrng for
>> > the random bits going into the kernel input pool, and a common
>> > default derating for drivers which do not specify one.
>> >
>> > Signed-off-by: Torsten Duwe <duwe@xxxxxxx>
>> >
>> > ---
>> > drivers/char/hw_random/core.c | 11 ++++++++++-
>> > include/linux/hw_random.h | 3 +++
>> > 2 files changed, 13 insertions(+), 1 deletion(-)
>> >
>> > --- linux/include/linux/hw_random.h.orig
>> > +++ linux/include/linux/hw_random.h
>> > @@ -29,6 +29,8 @@
>> > * @read: New API. drivers can fill up to max bytes of data
>> > * into the buffer. The buffer is aligned for any type.
>> > * @priv: Private data, for use by the RNG driver.
>> > + * @derating: Estimation of true entropy in RNG's bitstream
>> > + * (per mill).
>>
>> I'll bikeshed again: this is a rating, not a *de*rating. Higher =
>> more confidence, at least assuming the comment is right.
>>
> You're right. Would anyone object to call it "quality", as in RX signal quality?
> In context of a random source that is pretty accurate, I'd say. Other opinions?

I'm okay with "quality", although I'm still partial to "entropy_per_1000bits".

--Andy
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