team: introduce random mode

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: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 85 insertions, 21 deletions

diff --git a/drivers/net/team/Kconfig b/drivers/net/team/Kconfig
index c3011af68e91..c853d84fd99f 100644
--- a/drivers/net/team/Kconfig
+++ b/drivers/net/team/Kconfig
@@ -37,6 +37,18 @@ config NET_TEAM_MODE_ROUNDROBIN
           To compile this team mode as a module, choose M here: the module
           will be called team_mode_roundrobin.
 
+config NET_TEAM_MODE_RANDOM
+        tristate "Random mode support"
+        depends on NET_TEAM
+        ---help---
+          Basic mode where port used for transmitting packets is selected
+          randomly.
+
+          All added ports are setup to have team's device address.
+
+          To compile this team mode as a module, choose M here: the module
+          will be called team_mode_random.
+
 config NET_TEAM_MODE_ACTIVEBACKUP
         tristate "Active-backup mode support"
         depends on NET_TEAM
diff --git a/drivers/net/team/Makefile b/drivers/net/team/Makefile
index 975763014e5a..c57e85889751 100644
--- a/drivers/net/team/Makefile
+++ b/drivers/net/team/Makefile
@@ -5,5 +5,6 @@
 obj-$(CONFIG_NET_TEAM) += team.o
 obj-$(CONFIG_NET_TEAM_MODE_BROADCAST) += team_mode_broadcast.o
 obj-$(CONFIG_NET_TEAM_MODE_ROUNDROBIN) += team_mode_roundrobin.o
+obj-$(CONFIG_NET_TEAM_MODE_RANDOM) += team_mode_random.o
 obj-$(CONFIG_NET_TEAM_MODE_ACTIVEBACKUP) += team_mode_activebackup.o
 obj-$(CONFIG_NET_TEAM_MODE_LOADBALANCE) += team_mode_loadbalance.o
diff --git a/drivers/net/team/team_mode_random.c b/drivers/net/team/team_mode_random.c
new file mode 100644
index 000000000000..9eabfaa22f3e
--- /dev/null
+++ b/drivers/net/team/team_mode_random.c
@@ -0,0 +1,71 @@
+/*
+ * drivers/net/team/team_mode_random.c - Random mode for team
+ * Copyright (c) 2013 Jiri Pirko <jiri@resnulli.us>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#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(random32(), 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 = team_get_port_by_index_rcu(team, port_index);
+        port = team_get_first_port_txable_rcu(team, port);
+        if (unlikely(!port))
+                goto drop;
+        if (team_dev_queue_xmit(team, port, skb))
+                return false;
+        return true;
+
+drop:
+        dev_kfree_skb_any(skb);
+        return false;
+}
+
+static const struct team_mode_ops rnd_mode_ops = {
+        .transmit               = rnd_transmit,
+        .port_enter             = team_modeop_port_enter,
+        .port_change_dev_addr   = team_modeop_port_change_dev_addr,
+};
+
+static const struct team_mode rnd_mode = {
+        .kind           = "random",
+        .owner          = THIS_MODULE,
+        .ops            = &rnd_mode_ops,
+};
+
+static int __init rnd_init_module(void)
+{
+        return team_mode_register(&rnd_mode);
+}
+
+static void __exit rnd_cleanup_module(void)
+{
+        team_mode_unregister(&rnd_mode);
+}
+
+module_init(rnd_init_module);
+module_exit(rnd_cleanup_module);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>");
+MODULE_DESCRIPTION("Random mode for team");
+MODULE_ALIAS("team-mode-random");
diff --git a/drivers/net/team/team_mode_roundrobin.c b/drivers/net/team/team_mode_roundrobin.c
index ed63a6bc66ce..d268e4de781b 100644
--- a/drivers/net/team/team_mode_roundrobin.c
+++ b/drivers/net/team/team_mode_roundrobin.c
@@ -25,26 +25,6 @@ static struct rr_priv *rr_priv(struct team *team)
         return (struct rr_priv *) &team->mode_priv;
 }
 
-static struct team_port *__get_first_port_up(struct team *team,
-                                             struct team_port *port)
-{
-        struct team_port *cur;
-
-        if (team_port_txable(port))
-                return port;
-        cur = port;
-        list_for_each_entry_continue_rcu(cur, &team->port_list, list)
-                if (team_port_txable(port))
-                        return cur;
-        list_for_each_entry_rcu(cur, &team->port_list, list) {
-                if (cur == port)
-                        break;
-                if (team_port_txable(port))
-                        return cur;
-        }
-        return NULL;
-}
-
 static bool rr_transmit(struct team *team, struct sk_buff *skb)
 {
         struct team_port *port;
@@ -52,7 +32,7 @@ static bool rr_transmit(struct team *team, struct sk_buff *skb)
 
         port_index = rr_priv(team)->sent_packets++ % team->en_port_count;
         port = team_get_port_by_index_rcu(team, port_index);
-        port = __get_first_port_up(team, port);
+        port = team_get_first_port_txable_rcu(team, port);
         if (unlikely(!port))
                 goto drop;
         if (team_dev_queue_xmit(team, port, skb))