/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * include/net/dsa_stubs.h - Stubs for the Distributed Switch Architecture framework
 */

#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/net_tstamp.h>
#include <net/dsa.h>

#if IS_ENABLED(CONFIG_NET_DSA)

extern const struct dsa_stubs *dsa_stubs;

struct dsa_stubs {
    int (*master_hwtstamp_validate)(struct net_device *dev,
                    const struct kernel_hwtstamp_config *config,
                    struct netlink_ext_ack *extack);
};

static inline int dsa_master_hwtstamp_validate(struct net_device *dev,
                           const struct kernel_hwtstamp_config *config,
                           struct netlink_ext_ack *extack)
{
    if (!netdev_uses_dsa(dev))
        return 0;

    /* rtnl_lock() is a sufficient guarantee, because as long as
     * netdev_uses_dsa() returns true, the dsa_core module is still
     * registered, and so, dsa_unregister_stubs() couldn't have run.
     * For netdev_uses_dsa() to start returning false, it would imply that
     * dsa_master_teardown() has executed, which requires rtnl_lock().
     */
    ASSERT_RTNL();

    return dsa_stubs->master_hwtstamp_validate(dev, config, extack);
}

#else

static inline int dsa_master_hwtstamp_validate(struct net_device *dev,
                           const struct kernel_hwtstamp_config *config,
                           struct netlink_ext_ack *extack)
{
    return 0;
}

#endif