• Daniel Borkmann's avatar
    random32: add prandom_u32_max and convert open coded users · f337db64
    Daniel Borkmann authored
    Many functions have open coded a function that returns a random
    number in range [0,N-1]. Under the assumption that we have a PRNG
    such as taus113 with being well distributed in [0, ~0U] space,
    we can implement such a function as uword t = (n*m')>>32, where
    m' is a random number obtained from PRNG, n the right open interval
    border and t our resulting random number, with n,m',t in u32 universe.
    
    Lets go with Joe and simply call it prandom_u32_max(), although
    technically we have an right open interval endpoint, but that we
    have documented. Other users can further be migrated to the new
    prandom_u32_max() function later on; for now, we need to make sure
    to migrate reciprocal_divide() users for the reciprocal_divide()
    follow-up fixup since their function signatures are going to change.
    
    Joint work with Hannes Frederic Sowa.
    
    Cc: Jakub Zawadzki <darkjames-ws@darkjames.pl>
    Cc: Eric Dumazet <eric.dumazet@gmail.com>
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
    Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    f337db64
sch_choke.c 14.7 KB