bonding: move mode setting into separate function

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
new file mode 100644
index 0000000..294b766
--- /dev/null
+++ b/drivers/net/bonding/bond_options.c
@@ -0,0 +1,55 @@
+/*
+ * drivers/net/bond/bond_options.c - bonding options
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/errno.h>
+#include <linux/if.h>
+#include "bonding.h"
+
+static bool bond_mode_is_valid(int mode)
+{
+	int i;
+
+	for (i = 0; bond_mode_tbl[i].modename; i++);
+
+	return mode >= 0 && mode < i;
+}
+
+int bond_option_mode_set(struct bonding *bond, int mode)
+{
+	if (!bond_mode_is_valid(mode)) {
+		pr_err("invalid mode value %d.\n", mode);
+		return -EINVAL;
+	}
+
+	if (bond->dev->flags & IFF_UP) {
+		pr_err("%s: unable to update mode because interface is up.\n",
+		       bond->dev->name);
+		return -EPERM;
+	}
+
+	if (bond_has_slaves(bond)) {
+		pr_err("%s: unable to update mode because bond has slaves.\n",
+			bond->dev->name);
+		return -EPERM;
+	}
+
+	if (BOND_MODE_IS_LB(mode) && bond->params.arp_interval) {
+		pr_err("%s: %s mode is incompatible with arp monitoring.\n",
+		       bond->dev->name, bond_mode_tbl[mode].modename);
+		return -EINVAL;
+	}
+
+	/* don't cache arp_validate between modes */
+	bond->params.arp_validate = BOND_ARP_VALIDATE_NONE;
+	bond->params.mode = mode;
+	return 0;
+}