Merge branch 'dsa_master_ioctl-notifier'

Vladimir Oltean says:

====================
net: Convert dsa_master_ioctl() to netdev notifier

This is preparatory work in order for Maxim Georgiev to be able to start
the API conversion process of hardware timestamping from ndo_eth_ioctl()
to ndo_hwtstamp_set():
https://lore.kernel.org/netdev/20230331045619.40256-1-glipus@gmail.com/

In turn, Maxim Georgiev's work is a preparation so that Köry Maincent is
able to make the active hardware timestamping layer selectable by user
space.
https://lore.kernel.org/netdev/20230308135936.761794-1-kory.maincent@bootlin.com/

So, quite some dependency chain.

Before this patch set, DSA prevented the conversion of any networking
driver from the ndo_eth_ioctl() API to the ndo_hwtstamp_set() API,
because it wanted to validate the hwtstamping settings on the DSA
master, and it was only coded up to do this using the old API.

After this patch set, a new netdev notifier exists, which does not
depend on anything that would constitute the "soon-to-be-legacy" API,
but rather, it uses a newly introduced struct kernel_hwtstamp_config,
and it doesn't issue any ioctl at all, being thus compatible both with
ndo_eth_ioctl(), and with the not-yet-introduced, but now possible,
ndo_hwtstamp_set().
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/net_tstamp.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_NET_TIMESTAMPING_H_
+#define _LINUX_NET_TIMESTAMPING_H_
+
+#include <uapi/linux/net_tstamp.h>
+
+/**
+ * struct kernel_hwtstamp_config - Kernel copy of struct hwtstamp_config
+ *
+ * @flags: see struct hwtstamp_config
+ * @tx_type: see struct hwtstamp_config
+ * @rx_filter: see struct hwtstamp_config
+ *
+ * Prefer using this structure for in-kernel processing of hardware
+ * timestamping configuration, over the inextensible struct hwtstamp_config
+ * exposed to the %SIOCGHWTSTAMP and %SIOCSHWTSTAMP ioctl UAPI.
+ */
+struct kernel_hwtstamp_config {
+	int flags;
+	int tx_type;
+	int rx_filter;
+};
+
+static inline void hwtstamp_config_to_kernel(struct kernel_hwtstamp_config *kernel_cfg,
+					     const struct hwtstamp_config *cfg)
+{
+	kernel_cfg->flags = cfg->flags;
+	kernel_cfg->tx_type = cfg->tx_type;
+	kernel_cfg->rx_filter = cfg->rx_filter;
+}
+
+#endif /* _LINUX_NET_TIMESTAMPING_H_ */

include/linux/netdevice.h

@@ -2878,6 +2878,7 @@ enum netdev_cmd {
 	NETDEV_OFFLOAD_XSTATS_REPORT_USED,
 	NETDEV_OFFLOAD_XSTATS_REPORT_DELTA,
 	NETDEV_XDP_FEAT_CHANGE,
+	NETDEV_PRE_CHANGE_HWTSTAMP,
 };
 const char *netdev_cmd_to_name(enum netdev_cmd cmd);
 
@@ -2928,6 +2929,11 @@ struct netdev_notifier_pre_changeaddr_info {
 	const unsigned char *dev_addr;
 };
 
+struct netdev_notifier_hwtstamp_info {
+	struct netdev_notifier_info info; /* must be first */
+	struct kernel_hwtstamp_config *config;
+};
+
 enum netdev_offload_xstats_type {
 	NETDEV_OFFLOAD_XSTATS_TYPE_L3 = 1,
 };
@@ -2984,7 +2990,8 @@ netdev_notifier_info_to_extack(const struct netdev_notifier_info *info)
 }
 
 int call_netdevice_notifiers(unsigned long val, struct net_device *dev);
-
+int call_netdevice_notifiers_info(unsigned long val,
+				  struct netdev_notifier_info *info);
 
 extern rwlock_t				dev_base_lock;		/* Device list lock */
 

include/net/dsa.h

@@ -109,16 +109,6 @@ struct dsa_device_ops {
 	bool promisc_on_master;
 };
 
-/* This structure defines the control interfaces that are overlayed by the
- * DSA layer on top of the DSA CPU/management net_device instance. This is
- * used by the core net_device layer while calling various net_device_ops
- * function pointers.
- */
-struct dsa_netdevice_ops {
-	int (*ndo_eth_ioctl)(struct net_device *dev, struct ifreq *ifr,
-			     int cmd);
-};
-
 struct dsa_lag {
 	struct net_device *dev;
 	unsigned int id;
@@ -317,11 +307,6 @@ struct dsa_port {
 	 */
 	const struct ethtool_ops *orig_ethtool_ops;
 
-	/*
-	 * Original copy of the master netdev net_device_ops
-	 */
-	const struct dsa_netdevice_ops *netdev_ops;
-
 	/* List of MAC addresses that must be forwarded on this port.
 	 * These are only valid on CPU ports and DSA links.
 	 */
@@ -1339,42 +1324,6 @@ static inline void dsa_tag_generic_flow_dissect(const struct sk_buff *skb,
 #endif
 }
 
-#if IS_ENABLED(CONFIG_NET_DSA)
-static inline int __dsa_netdevice_ops_check(struct net_device *dev)
-{
-	int err = -EOPNOTSUPP;
-
-	if (!dev->dsa_ptr)
-		return err;
-
-	if (!dev->dsa_ptr->netdev_ops)
-		return err;
-
-	return 0;
-}
-
-static inline int dsa_ndo_eth_ioctl(struct net_device *dev, struct ifreq *ifr,
-				    int cmd)
-{
-	const struct dsa_netdevice_ops *ops;
-	int err;
-
-	err = __dsa_netdevice_ops_check(dev);
-	if (err)
-		return err;
-
-	ops = dev->dsa_ptr->netdev_ops;
-
-	return ops->ndo_eth_ioctl(dev, ifr, cmd);
-}
-#else
-static inline int dsa_ndo_eth_ioctl(struct net_device *dev, struct ifreq *ifr,
-				    int cmd)
-{
-	return -EOPNOTSUPP;
-}
-#endif
-
 void dsa_unregister_switch(struct dsa_switch *ds);
 int dsa_register_switch(struct dsa_switch *ds);
 void dsa_switch_shutdown(struct dsa_switch *ds);

net/core/dev.c

@@ -160,8 +160,6 @@ struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
 struct list_head ptype_all __read_mostly;	/* Taps */
 
 static int netif_rx_internal(struct sk_buff *skb);
-static int call_netdevice_notifiers_info(unsigned long val,
-					 struct netdev_notifier_info *info);
 static int call_netdevice_notifiers_extack(unsigned long val,
 					   struct net_device *dev,
 					   struct netlink_ext_ack *extack);
@@ -1614,7 +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(XDP_FEAT_CHANGE) N(PRE_CHANGE_HWTSTAMP)
 	}
 #undef N
 	return "UNKNOWN_NETDEV_EVENT";
@@ -1919,7 +1917,7 @@ static void move_netdevice_notifiers_dev_net(struct net_device *dev,
  *	are as for raw_notifier_call_chain().
  */
 
-static int call_netdevice_notifiers_info(unsigned long val,
+int call_netdevice_notifiers_info(unsigned long val,
 				  struct netdev_notifier_info *info)
 {
 	struct net *net = dev_net(info->dev);

net/core/dev_ioctl.c

@@ -183,22 +183,18 @@ static int dev_ifsioc_locked(struct net *net, struct ifreq *ifr, unsigned int cm
 	return err;
 }
 
-static int net_hwtstamp_validate(struct ifreq *ifr)
+static int net_hwtstamp_validate(const struct kernel_hwtstamp_config *cfg)
 {
-	struct hwtstamp_config cfg;
 	enum hwtstamp_tx_types tx_type;
 	enum hwtstamp_rx_filters rx_filter;
 	int tx_type_valid = 0;
 	int rx_filter_valid = 0;
 
-	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
-		return -EFAULT;
-
-	if (cfg.flags & ~HWTSTAMP_FLAG_MASK)
+	if (cfg->flags & ~HWTSTAMP_FLAG_MASK)
 		return -EINVAL;
 
-	tx_type = cfg.tx_type;
-	rx_filter = cfg.rx_filter;
+	tx_type = cfg->tx_type;
+	rx_filter = cfg->rx_filter;
 
 	switch (tx_type) {
 	case HWTSTAMP_TX_OFF:
@@ -246,20 +242,53 @@ static int dev_eth_ioctl(struct net_device *dev,
 			 struct ifreq *ifr, unsigned int cmd)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
+
+	if (!ops->ndo_eth_ioctl)
+		return -EOPNOTSUPP;
+
+	if (!netif_device_present(dev))
+		return -ENODEV;
+
+	return ops->ndo_eth_ioctl(dev, ifr, cmd);
+}
+
+static int dev_get_hwtstamp(struct net_device *dev, struct ifreq *ifr)
+{
+	return dev_eth_ioctl(dev, ifr, SIOCGHWTSTAMP);
+}
+
+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;
 	int err;
 
-	err = dsa_ndo_eth_ioctl(dev, ifr, cmd);
-	if (err == 0 || err != -EOPNOTSUPP)
+	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
+		return -EFAULT;
+
+	hwtstamp_config_to_kernel(&kernel_cfg, &cfg);
+
+	err = net_hwtstamp_validate(&kernel_cfg);
+	if (err)
 		return err;
 
-	if (ops->ndo_eth_ioctl) {
-		if (netif_device_present(dev))
-			err = ops->ndo_eth_ioctl(dev, ifr, cmd);
-		else
-			err = -ENODEV;
-	}
+	info.info.extack = &extack;
+	info.config = &kernel_cfg;
 
+	err = call_netdevice_notifiers_info(NETDEV_PRE_CHANGE_HWTSTAMP,
+					    &info.info);
+	err = notifier_to_errno(err);
+	if (err) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
 		return err;
+	}
+
+	return dev_eth_ioctl(dev, ifr, SIOCSHWTSTAMP);
 }
 
 static int dev_siocbond(struct net_device *dev,
@@ -391,36 +420,31 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, void __user *data,
 		rtnl_lock();
 		return err;
 
+	case SIOCDEVPRIVATE ... SIOCDEVPRIVATE + 15:
+		return dev_siocdevprivate(dev, ifr, data, cmd);
+
 	case SIOCSHWTSTAMP:
-		err = net_hwtstamp_validate(ifr);
-		if (err)
-			return err;
-		fallthrough;
+		return dev_set_hwtstamp(dev, ifr);
 
-	/*
-	 *	Unknown or private ioctl
-	 */
-	default:
-		if (cmd >= SIOCDEVPRIVATE &&
-		    cmd <= SIOCDEVPRIVATE + 15)
-			return dev_siocdevprivate(dev, ifr, data, cmd);
+	case SIOCGHWTSTAMP:
+		return dev_get_hwtstamp(dev, ifr);
 
-		if (cmd == SIOCGMIIPHY ||
-		    cmd == SIOCGMIIREG ||
-		    cmd == SIOCSMIIREG ||
-		    cmd == SIOCSHWTSTAMP ||
-		    cmd == SIOCGHWTSTAMP) {
-			err = dev_eth_ioctl(dev, ifr, cmd);
-		} else if (cmd == SIOCBONDENSLAVE ||
-		    cmd == SIOCBONDRELEASE ||
-		    cmd == SIOCBONDSETHWADDR ||
-		    cmd == SIOCBONDSLAVEINFOQUERY ||
-		    cmd == SIOCBONDINFOQUERY ||
-		    cmd == SIOCBONDCHANGEACTIVE) {
-			err = dev_siocbond(dev, ifr, cmd);
-		} else
-			err = -EINVAL;
+	case SIOCGMIIPHY:
+	case SIOCGMIIREG:
+	case SIOCSMIIREG:
+		return dev_eth_ioctl(dev, ifr, cmd);
+
+	case SIOCBONDENSLAVE:
+	case SIOCBONDRELEASE:
+	case SIOCBONDSETHWADDR:
+	case SIOCBONDSLAVEINFOQUERY:
+	case SIOCBONDINFOQUERY:
+	case SIOCBONDCHANGEACTIVE:
+		return dev_siocbond(dev, ifr, cmd);
 
+	/* Unknown ioctl */
+	default:
+		err = -EINVAL;
 	}
 	return err;
 }

net/dsa/master.c

@@ -195,38 +195,31 @@ static void dsa_master_get_strings(struct net_device *dev, uint32_t stringset,
 	}
 }
 
-static int dsa_master_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+/* 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,
+				   const struct kernel_hwtstamp_config *config,
+				   struct netlink_ext_ack *extack)
 {
 	struct dsa_port *cpu_dp = dev->dsa_ptr;
 	struct dsa_switch *ds = cpu_dp->ds;
 	struct dsa_switch_tree *dst;
-	int err = -EOPNOTSUPP;
 	struct dsa_port *dp;
 
 	dst = ds->dst;
 
-	switch (cmd) {
-	case SIOCGHWTSTAMP:
-	case SIOCSHWTSTAMP:
-		/* Deny PTP operations on master if there is at least one
-		 * switch in the tree that is PTP capable.
-		 */
-		list_for_each_entry(dp, &dst->ports, list)
-			if (dsa_port_supports_hwtstamp(dp, ifr))
+	list_for_each_entry(dp, &dst->ports, list) {
+		if (dsa_port_supports_hwtstamp(dp)) {
+			NL_SET_ERR_MSG(extack,
+				       "HW timestamping not allowed on DSA master when switch supports the operation");
 			return -EBUSY;
-		break;
+		}
 	}
 
-	if (dev->netdev_ops->ndo_eth_ioctl)
-		err = dev->netdev_ops->ndo_eth_ioctl(dev, ifr, cmd);
-
-	return err;
+	return 0;
 }
 
-static const struct dsa_netdevice_ops dsa_netdev_ops = {
-	.ndo_eth_ioctl = dsa_master_ioctl,
-};
-
 static int dsa_master_ethtool_setup(struct net_device *dev)
 {
 	struct dsa_port *cpu_dp = dev->dsa_ptr;
@@ -267,15 +260,6 @@ static void dsa_master_ethtool_teardown(struct net_device *dev)
 	cpu_dp->orig_ethtool_ops = NULL;
 }
 
-static void dsa_netdev_ops_set(struct net_device *dev,
-			       const struct dsa_netdevice_ops *ops)
-{
-	if (netif_is_lag_master(dev))
-		return;
-
-	dev->dsa_ptr->netdev_ops = ops;
-}
-
 /* Keep the master always promiscuous if the tagging protocol requires that
  * (garbles MAC DA) or if it doesn't support unicast filtering, case in which
  * it would revert to promiscuous mode as soon as we call dev_uc_add() on it
@@ -414,16 +398,13 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 	if (ret)
 		goto out_err_reset_promisc;
 
-	dsa_netdev_ops_set(dev, &dsa_netdev_ops);
-
 	ret = sysfs_create_group(&dev->dev.kobj, &dsa_group);
 	if (ret)
-		goto out_err_ndo_teardown;
+		goto out_err_ethtool_teardown;
 
 	return ret;
 
-out_err_ndo_teardown:
-	dsa_netdev_ops_set(dev, NULL);
+out_err_ethtool_teardown:
 	dsa_master_ethtool_teardown(dev);
 out_err_reset_promisc:
 	dsa_master_set_promiscuity(dev, -1);
@@ -433,7 +414,6 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
 void dsa_master_teardown(struct net_device *dev)
 {
 	sysfs_remove_group(&dev->dev.kobj, &dsa_group);
-	dsa_netdev_ops_set(dev, NULL);
 	dsa_master_ethtool_teardown(dev);
 	dsa_master_reset_mtu(dev);
 	dsa_master_set_promiscuity(dev, -1);

net/dsa/master.h

@@ -15,5 +15,8 @@ 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,
+				   const struct kernel_hwtstamp_config *config,
+				   struct netlink_ext_ack *extack);
 
 #endif

net/dsa/port.c

@@ -114,19 +114,21 @@ static bool dsa_port_can_configure_learning(struct dsa_port *dp)
 	return !err;
 }
 
-bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr)
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp)
 {
 	struct dsa_switch *ds = dp->ds;
+	struct ifreq ifr = {};
 	int err;
 
 	if (!ds->ops->port_hwtstamp_get || !ds->ops->port_hwtstamp_set)
 		return false;
 
 	/* "See through" shim implementations of the "get" method.
-	 * This will clobber the ifreq structure, but we will either return an
-	 * error, or the master will overwrite it with proper values.
+	 * Since we can't cook up a complete ioctl request structure, this will
+	 * fail in copy_to_user() with -EFAULT, which hopefully is enough to
+	 * detect a valid implementation.
 	 */
-	err = ds->ops->port_hwtstamp_get(ds, dp->index, ifr);
+	err = ds->ops->port_hwtstamp_get(ds, dp->index, &ifr);
 	return err != -EOPNOTSUPP;
 }
 

net/dsa/port.h

@@ -15,7 +15,7 @@ struct switchdev_obj_port_mdb;
 struct switchdev_vlan_msti;
 struct phy_device;
 
-bool dsa_port_supports_hwtstamp(struct dsa_port *dp, struct ifreq *ifr);
+bool dsa_port_supports_hwtstamp(struct dsa_port *dp);
 void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
 			       const struct dsa_device_ops *tag_ops);
 int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);

net/dsa/slave.c

@@ -3289,6 +3289,7 @@ 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) {
@@ -3418,6 +3419,16 @@ 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;
 	}