Re: [PATCH 28/29] net/: rename net_random() to prandom_u32()

Neil Horman
2012-12-26T00:42:31Z

On Tue, Dec 25, 2012 at 08:47:26PM +0900, Akinobu Mita wrote:
> 2012/12/25 Neil Horman <nhorman@tuxdriver.com>:
> > On Mon, Dec 24, 2012 at 11:14:15AM +0900, Akinobu Mita wrote:
> >> Use more preferable function name which implies using a pseudo-random
> >> number generator.
> >>
> >> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> >> Cc: Jesse Gross <jesse@nicira.com>
> >> Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
> >> Cc: Vlad Yasevich <vyasevich@gmail.com>
> >> Cc: Sridhar Samudrala <sri@us.ibm.com>
> >> Cc: Neil Horman <nhorman@tuxdriver.com>
> >> Cc: Steffen Klassert <steffen.klassert@secunet.com>
> >> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> >> Cc: "David S. Miller" <davem@davemloft.net>
> >> Cc: linux-sctp@vger.kernel.org
> >> Cc: dev@openvswitch.org
> >> Cc: netdev@vger.kernel.org
> >> ---
> >> include/net/red.h | 2 +-
> >> net/802/garp.c | 2 +-
> >> net/openvswitch/actions.c | 2 +-
> >> net/rds/bind.c | 2 +-
> >> net/sctp/socket.c | 2 +-
> >> net/xfrm/xfrm_state.c | 2 +-
> >> 6 files changed, 6 insertions(+), 6 deletions(-)
> >>
> > I'm largely indifferent to this patch, but I kind of feel like its just churn.
> > Whats the real advantage in making this change? I grant that it clearly
> > indicates the type of random number generator we're using at a given call site,
> > But for those using net_random, you probably don't care too much about
> > the source of your random bits. If you did really want true random vs.
> > pseudo-random data, you need to explicitly use the right call. You're previous
> > patch series did good cleanup on differentiating the different random calls, but
> > this just seems like its removing what is otherwise useful indirection.
>
> I overlooked the importance of net_random() indirection.
> Thanks for the feedback. I'll leave all net_random() callers as-is in
> the next version.
Well, I guess I should qualify my opinion. I find it useful personally (the
generation of nonces in many cases can be left to most any pseudo random
generator that the system deems is a 'good enough' balance between a fast
generator that doesn't block on low entropy and a reasonably secure one that
doesn't allow for easy prediction. As those needs and factors change, its nice
to have a set point to change them at. If you (or anyone else has a differing
opinion, I'm happy to listen to it.

Regards
Neil

>