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: NHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

team_get_port_by_index_rcu() might return NULL due to race between port
removal and skb tx path. Panic is easily triggeable when txing packets
and adding/removing port in a loop.

introduced by commit 3d249d4c "net: introduce ethernet teaming device"
and commit 753f9939 "team: introduce random mode" (for random mode)
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use preferable function name which implies using a pseudo-random number
generator.

[akpm@linux-foundation.org: convert team_mode_random.c]
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NThomas Sailer <t.sailer@alumni.ethz.ch>
Acked-by: Bing Zhao <bzhao@marvell.com> [mwifiex]
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Thomas Sailer <t.sailer@alumni.ethz.ch>
Cc: Jean-Paul Roubelat <jpr@f6fbb.org>
Cc: Bing Zhao <bzhao@marvell.com>
Cc: Brett Rudley <brudley@broadcom.com>
Cc: Arend van Spriel <arend@broadcom.com>
Cc: "Franky (Zhenhui) Lin" <frankyl@broadcom.com>
Cc: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As suggested by Eric Dumazet, allow user to select mode which chooses
TX port randomly. Functionality should be more of less similar to
round-robin mode with even lower overhead.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>