path: root/net/switchdev/switchdev.c

/*
 * net/switchdev/switchdev.c - Switch device API
 * Copyright (c) 2014 Jiri Pirko <jiri@resnulli.us>
 * Copyright (c) 2014-2015 Scott Feldman <sfeldma@gmail.com>
 *
 * 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/init.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/if_bridge.h>
#include <net/ip_fib.h>
#include <net/switchdev.h>

/**
 *	switchdev_port_attr_get - Get port attribute
 *
 *	@dev: port device
 *	@attr: attribute to get
 */
int switchdev_port_attr_get(struct net_device *dev, struct switchdev_attr *attr)
{
	const struct switchdev_ops *ops = dev->switchdev_ops;
	struct net_device *lower_dev;
	struct list_head *iter;
	struct switchdev_attr first = {
		.id = SWITCHDEV_ATTR_UNDEFINED
	};
	int err = -EOPNOTSUPP;

	if (ops && ops->switchdev_port_attr_get)
		return ops->switchdev_port_attr_get(dev, attr);

	if (attr->flags & SWITCHDEV_F_NO_RECURSE)
		return err;

	/* Switch device port(s) may be stacked under
	 * bond/team/vlan dev, so recurse down to get attr on
	 * each port.  Return -ENODATA if attr values don't
	 * compare across ports.
	 */

	netdev_for_each_lower_dev(dev, lower_dev, iter) {
		err = switchdev_port_attr_get(lower_dev, attr);
		if (err)
			break;
		if (first.id == SWITCHDEV_ATTR_UNDEFINED)
			first = *attr;
		else if (memcmp(&first, attr, sizeof(*attr)))
			return -ENODATA;
	}

	return err;
}
EXPORT_SYMBOL_GPL(switchdev_port_attr_get);

static int __switchdev_port_attr_set(struct net_device *dev,
				     struct switchdev_attr *attr)
{
	const struct switchdev_ops *ops = dev->switchdev_ops;
	struct net_device *lower_dev;
	struct list_head *iter;
	int err = -EOPNOTSUPP;

	if (ops && ops->switchdev_port_attr_set)
		return ops->switchdev_port_attr_set(dev, attr);

	if (attr->flags & SWITCHDEV_F_NO_RECURSE)
		return err;

	/* Switch device port(s) may be stacked under
	 * bond/team/vlan dev, so recurse down to set attr on
	 * each port.
	 */

	netdev_for_each_lower_dev(dev, lower_dev, iter) {
		err = __switchdev_port_attr_set(lower_dev, attr);
		if (err)
			break;
	}

	return err;
}

struct switchdev_attr_set_work {
	struct work_struct work;
	struct net_device *dev;
	struct switchdev_attr attr;
};

static void switchdev_port_attr_set_work(struct work_struct *work)
{
	struct switchdev_attr_set_work *asw =
		container_of(work, struct switchdev_attr_set_work, work);
	int err;

	rtnl_lock();
	err = switchdev_port_attr_set(asw->dev, &asw->attr);
	if (err && err != -EOPNOTSUPP)
		netdev_err(asw->dev, "failed (err=%d) to set attribute (id=%d)\n",
			   err, asw->attr.id);
	rtnl_unlock();

	dev_put(asw->dev);
	kfree(work);
}

static int switchdev_port_attr_set_defer(struct net_device *dev,
					 struct switchdev_attr *attr)
{
	struct switchdev_attr_set_work *asw;

	asw = kmalloc(sizeof(*asw), GFP_ATOMIC);
	if (!asw)
		return -ENOMEM;

	INIT_WORK(&asw->work, switchdev_port_attr_set_work);

	dev_hold(dev);
	asw->dev = dev;
	memcpy(&asw->attr, attr, sizeof(asw->attr));

	schedule_work(&asw->work);

	return 0;
}

/**
 *	switchdev_port_attr_set - Set port attribute
 *
 *	@dev: port device
 *	@attr: attribute to set
 *
 *	Use a 2-phase prepare-commit transaction model to ensure
 *	system is not left in a partially updated state due to
 *	failure from driver/device.
 */
int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
{
	int err;

	if (!rtnl_is_locked()) {
		/* Running prepare-commit transaction across stacked
		 * devices requires nothing moves, so if rtnl_lock is
		 * not held, schedule a worker thread to hold rtnl_lock
		 * while setting attr.
		 */

		return switchdev_port_attr_set_defer(dev, attr);
	}

	/* Phase I: prepare for attr set. Driver/device should fail
	 * here if there are going to be issues in the commit phase,
	 * such as lack of resources or support.  The driver/device
	 * should reserve resources needed for the commit phase here,
	 * but should not commit the attr.
	 */

	attr->trans_ph = SWITCHDEV_TRANS_PREPARE;
	err = __switchdev_port_attr_set(dev, attr);
	if (err) {
		/* Prepare phase failed: abort the transaction.  Any
		 * resources reserved in the prepare phase are
		 * released.
		 */

		if (err != -EOPNOTSUPP) {
			attr