9 files changed, 41 insertions, 25 deletions
diff --git a/net/Makefile b/net/Makefile
index 0914bea9c335..87592009366f 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -24,7 +24,7 @@ obj-$(CONFIG_PACKET)		+= packet/
 obj-$(CONFIG_NET_KEY)		+= key/
 obj-$(CONFIG_BRIDGE)		+= bridge/
 obj-$(CONFIG_NET_DEVLINK)	+= devlink/
-obj-$(CONFIG_NET_DSA)		+= dsa/
+obj-y				+= dsa/
 obj-$(CONFIG_ATALK)		+= appletalk/
 obj-$(CONFIG_X25)		+= x25/
 obj-$(CONFIG_LAPB)		+= lapb/
diff --git a/net/core/dev.c b/net/core/dev.c
index 7ce5985be84b..480600a075ce 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1612,7 +1612,7 @@ const char *netdev_cmd_to_name(enum netdev_cmd cmd)
 	N(SVLAN_FILTER_PUSH_INFO) N(SVLAN_FILTER_DROP_INFO)
 	N(PRE_CHANGEADDR) N(OFFLOAD_XSTATS_ENABLE) N(OFFLOAD_XSTATS_DISABLE)
 	N(OFFLOAD_XSTATS_REPORT_USED) N(OFFLOAD_XSTATS_REPORT_DELTA)
-	N(XDP_FEAT_CHANGE) N(PRE_CHANGE_HWTSTAMP)
+	N(XDP_FEAT_CHANGE)
 	}
 #undef N
 	return "UNKNOWN_NETDEV_EVENT";
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 6d772837eb3f..3730945ee294 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -7,7 +7,7 @@
 #include <linux/net_tstamp.h>
 #include <linux/wireless.h>
 #include <linux/if_bridge.h>
-#include <net/dsa.h>
+#include <net/dsa_stubs.h>
 #include <net/wext.h>
 
 #include "dev.h"
@@ -259,9 +259,6 @@ static int dev_get_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 
 static int dev_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 {
-	struct netdev_notifier_hwtstamp_info info = {
-		.info.dev = dev,
-	};
 	struct kernel_hwtstamp_config kernel_cfg;
 	struct netlink_ext_ack extack = {};
 	struct hwtstamp_config cfg;
@@ -276,12 +273,7 @@ static int dev_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
 	if (err)
 		return err;
 
-	info.info.extack = &extack;
-	info.config = &kernel_cfg;
-
-	err = call_netdevice_notifiers_info(NETDEV_PRE_CHANGE_HWTSTAMP,
-					    &info.info);
-	err = notifier_to_errno(err);
+	err = dsa_master_hwtstamp_validate(dev, &kernel_cfg, &extack);
 	if (err) {
 		if (extack._msg)
 			netdev_err(dev, "%s\n", extack._msg);
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index cc7e93a562fe..3835de286116 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -1,4 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0
+
+# the stubs are built-in whenever DSA is built-in or module
+ifdef CONFIG_NET_DSA
+obj-y := stubs.o
+endif
+
 # the core
 obj-$(CONFIG_NET_DSA) += dsa_core.o
 dsa_core-y += \
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index e5f156940c67..ab1afe67fd18 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -17,6 +17,7 @@
 #include <linux/of.h>
 #include <linux/of_mdio.h>
 #include <linux/of_net.h>
+#include <net/dsa_stubs.h>
 #include <net/sch_generic.h>
 
 #include "devlink.h"
@@ -1702,6 +1703,20 @@ bool dsa_mdb_present_in_other_db(struct dsa_switch *ds, int port,
 }
 EXPORT_SYMBOL_GPL(dsa_mdb_present_in_other_db);
 
+static const struct dsa_stubs __dsa_stubs = {
+	.master_hwtstamp_validate = __dsa_master_hwtstamp_validate,
+};
+
+static void dsa_register_stubs(void)
+{
+	dsa_stubs = &__dsa_stubs;
+}
+
+static void dsa_unregister_stubs(void)
+{
+	dsa_stubs = NULL;
+}
+
 static int __init dsa_init_module(void)
 {
 	int rc;
@@ -1721,6 +1736,8 @@ static int __init dsa_init_module(void)
 	if (rc)
 		goto netlink_register_fail;
 
+	dsa_register_stubs();
+
 	return 0;
 
 netlink_register_fail:
@@ -1735,6 +1752,8 @@ module_init(dsa_init_module);
 
 static void __exit dsa_cleanup_module(void)
 {
+	dsa_unregister_stubs();
+
 	rtnl_link_unregister(&dsa_link_ops);
 
 	dsa_slave_unregister_notifier();
diff --git a/net/dsa/master.c b/net/dsa/master.c
index c2cabe6248b1..6be89ab0cc01 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -198,7 +198,7 @@ static void dsa_master_get_strings(struct net_device *dev, uint32_t stringset,
 /* Deny PTP operations on master if there is at least one switch in the tree
  * that is PTP capable.
  */
-int dsa_master_pre_change_hwtstamp(struct net_device *dev,
+int __dsa_master_hwtstamp_validate(struct net_device *dev,
 				   const struct kernel_hwtstamp_config *config,
 				   struct netlink_ext_ack *extack)
 {
diff --git a/net/dsa/master.h b/net/dsa/master.h
index 80842f4e27f7..76e39d3ec909 100644
--- a/net/dsa/master.h
+++ b/net/dsa/master.h
@@ -15,7 +15,7 @@ int dsa_master_lag_setup(struct net_device *lag_dev, struct dsa_port *cpu_dp,
 			 struct netlink_ext_ack *extack);
 void dsa_master_lag_teardown(struct net_device *lag_dev,
 			     struct dsa_port *cpu_dp);
-int dsa_master_pre_change_hwtstamp(struct net_device *dev,
+int __dsa_master_hwtstamp_validate(struct net_device *dev,
 				   const struct kernel_hwtstamp_config *config,
 				   struct netlink_ext_ack *extack);
 
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 8abc1658ac47..165bb2cb8431 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -3289,7 +3289,6 @@ static int dsa_master_changeupper(struct net_device *dev,
 static int dsa_slave_netdevice_event(struct notifier_block *nb,
 				     unsigned long event, void *ptr)
 {
-	struct netlink_ext_ack *extack = netdev_notifier_info_to_extack(ptr);
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
 	switch (event) {
@@ -3419,16 +3418,6 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
 
 		return NOTIFY_OK;
 	}
-	case NETDEV_PRE_CHANGE_HWTSTAMP: {
-		struct netdev_notifier_hwtstamp_info *info = ptr;
-		int err;
-
-		if (!netdev_uses_dsa(dev))
-			return NOTIFY_DONE;
-
-		err = dsa_master_pre_change_hwtstamp(dev, info->config, extack);
-		return notifier_from_errno(err);
-	}
 	default:
 		break;
 	}
diff --git a/net/dsa/stubs.c b/net/dsa/stubs.c
new file mode 100644
index 000000000000..2ed8a6c85fbf
--- /dev/null
+++ b/net/dsa/stubs.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Stubs for DSA functionality called by the core network stack.
+ * These are necessary because CONFIG_NET_DSA can be a module, and built-in
+ * code cannot directly call symbols exported by modules.
+ */
+#include <net/dsa_stubs.h>
+
+const struct dsa_stubs *dsa_stubs;
+EXPORT_SYMBOL_GPL(dsa_stubs);