1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * include/net/dsa_stubs.h - Stubs for the Distributed Switch Architecture framework
4  */
5 
6 #include <linux/mutex.h>
7 #include <linux/netdevice.h>
8 #include <linux/net_tstamp.h>
9 #include <net/dsa.h>
10 
11 #if IS_ENABLED(CONFIG_NET_DSA)
12 
13 extern const struct dsa_stubs *dsa_stubs;
14 
15 struct dsa_stubs {
16 	int (*conduit_hwtstamp_validate)(struct net_device *dev,
17 					 const struct kernel_hwtstamp_config *config,
18 					 struct netlink_ext_ack *extack);
19 };
20 
dsa_conduit_hwtstamp_validate(struct net_device * dev,const struct kernel_hwtstamp_config * config,struct netlink_ext_ack * extack)21 static inline int dsa_conduit_hwtstamp_validate(struct net_device *dev,
22 						const struct kernel_hwtstamp_config *config,
23 						struct netlink_ext_ack *extack)
24 {
25 	if (!netdev_uses_dsa(dev))
26 		return 0;
27 
28 	/* rtnl_lock() is a sufficient guarantee, because as long as
29 	 * netdev_uses_dsa() returns true, the dsa_core module is still
30 	 * registered, and so, dsa_unregister_stubs() couldn't have run.
31 	 * For netdev_uses_dsa() to start returning false, it would imply that
32 	 * dsa_conduit_teardown() has executed, which requires rtnl_lock().
33 	 */
34 	ASSERT_RTNL();
35 
36 	return dsa_stubs->conduit_hwtstamp_validate(dev, config, extack);
37 }
38 
39 #else
40 
dsa_conduit_hwtstamp_validate(struct net_device * dev,const struct kernel_hwtstamp_config * config,struct netlink_ext_ack * extack)41 static inline int dsa_conduit_hwtstamp_validate(struct net_device *dev,
42 						const struct kernel_hwtstamp_config *config,
43 						struct netlink_ext_ack *extack)
44 {
45 	return 0;
46 }
47 
48 #endif
49