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f337db64af
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>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/*
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* drivers/net/team/team_mode_random.c - Random mode for team
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* Copyright (c) 2013 Jiri Pirko <jiri@resnulli.us>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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#include <linux/if_team.h>
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static bool rnd_transmit(struct team *team, struct sk_buff *skb)
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{
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struct team_port *port;
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int port_index;
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port_index = prandom_u32_max(team->en_port_count);
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port = team_get_port_by_index_rcu(team, port_index);
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if (unlikely(!port))
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goto drop;
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port = team_get_first_port_txable_rcu(team, port);
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if (unlikely(!port))
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goto drop;
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if (team_dev_queue_xmit(team, port, skb))
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return false;
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return true;
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drop:
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dev_kfree_skb_any(skb);
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return false;
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}
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static const struct team_mode_ops rnd_mode_ops = {
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.transmit = rnd_transmit,
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.port_enter = team_modeop_port_enter,
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.port_change_dev_addr = team_modeop_port_change_dev_addr,
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};
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static const struct team_mode rnd_mode = {
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.kind = "random",
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.owner = THIS_MODULE,
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.ops = &rnd_mode_ops,
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};
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static int __init rnd_init_module(void)
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{
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return team_mode_register(&rnd_mode);
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}
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static void __exit rnd_cleanup_module(void)
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{
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team_mode_unregister(&rnd_mode);
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}
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module_init(rnd_init_module);
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module_exit(rnd_cleanup_module);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
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MODULE_DESCRIPTION("Random mode for team");
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MODULE_ALIAS("team-mode-random");
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