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author | Daniel Borkmann <dborkman@redhat.com> | 2014-01-22 02:29:39 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2014-01-21 23:17:20 -0800 |
commit | f337db64af059c9a94278a8b0ab97d87259ff62f (patch) | |
tree | ef7db2258d5929760f2a22b74779d374916634bd /drivers/net/team | |
parent | 6cd28f044b47aeeba91807d97d6f3ea5a048e88d (diff) | |
download | linux-f337db64af059c9a94278a8b0ab97d87259ff62f.tar.gz |
random32: add prandom_u32_max and convert open coded users
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: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/team')
-rw-r--r-- | drivers/net/team/team_mode_random.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/drivers/net/team/team_mode_random.c b/drivers/net/team/team_mode_random.c index 7f032e211343..cd2f692b8074 100644 --- a/drivers/net/team/team_mode_random.c +++ b/drivers/net/team/team_mode_random.c @@ -13,20 +13,14 @@ #include <linux/module.h> #include <linux/init.h> #include <linux/skbuff.h> -#include <linux/reciprocal_div.h> #include <linux/if_team.h> -static u32 random_N(unsigned int N) -{ - return reciprocal_divide(prandom_u32(), N); -} - static bool rnd_transmit(struct team *team, struct sk_buff *skb) { struct team_port *port; int port_index; - port_index = random_N(team->en_port_count); + port_index = prandom_u32_max(team->en_port_count); port = team_get_port_by_index_rcu(team, port_index); if (unlikely(!port)) goto drop; |