net: move misc netdev_lock flavors to a separate header

Move the more esoteric helpers for netdev instance lock to
a dedicated header. This avoids growing netdevice.h to infinity
and makes rebuilding the kernel much faster (after touching
the header with the helpers).

The main netdev_lock() / netdev_unlock() functions are used
in static inlines in netdevice.h and will probably be used
most commonly, so keep them in netdevice.h.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250307183006.2312761-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 90 insertions, 80 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d206c9592b60..9a297757df7e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2630,40 +2630,6 @@ static inline void netdev_for_each_tx_queue(struct net_device *dev,
 		f(dev, &dev->_tx[i], arg);
 }
 
-static inline int netdev_lock_cmp_fn(const struct lockdep_map *a,
-				     const struct lockdep_map *b)
-{
-	/* Only lower devices currently grab the instance lock, so no
-	 * real ordering issues can occur. In the near future, only
-	 * hardware devices will grab instance lock which also does not
-	 * involve any ordering. Suppress lockdep ordering warnings
-	 * until (if) we start grabbing instance lock on pure SW
-	 * devices (bond/team/veth/etc).
-	 */
-	if (a == b)
-		return 0;
-	return -1;
-}
-
-#define netdev_lockdep_set_classes(dev)				\
-{								\
-	static struct lock_class_key qdisc_tx_busylock_key;	\
-	static struct lock_class_key qdisc_xmit_lock_key;	\
-	static struct lock_class_key dev_addr_list_lock_key;	\
-	static struct lock_class_key dev_instance_lock_key;	\
-	unsigned int i;						\
-								\
-	(dev)->qdisc_tx_busylock = &qdisc_tx_busylock_key;	\
-	lockdep_set_class(&(dev)->addr_list_lock,		\
-			  &dev_addr_list_lock_key);		\
-	lockdep_set_class(&(dev)->lock,				\
-			  &dev_instance_lock_key);		\
-	lock_set_cmp_fn(&dev->lock, netdev_lock_cmp_fn, NULL);	\
-	for (i = 0; i < (dev)->num_tx_queues; i++)		\
-		lockdep_set_class(&(dev)->_tx[i]._xmit_lock,	\
-				  &qdisc_xmit_lock_key);	\
-}
-
 u16 netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
 		     struct net_device *sb_dev);
 struct netdev_queue *netdev_core_pick_tx(struct net_device *dev,
@@ -2765,56 +2731,11 @@ static inline void netdev_lock(struct net_device *dev)
 	mutex_lock(&dev->lock);
 }
 
-static inline bool netdev_trylock(struct net_device *dev)
-{
-	return mutex_trylock(&dev->lock);
-}
-
 static inline void netdev_unlock(struct net_device *dev)
 {
 	mutex_unlock(&dev->lock);
 }
-
-static inline void netdev_assert_locked(struct net_device *dev)
-{
-	lockdep_assert_held(&dev->lock);
-}
-
-static inline void netdev_assert_locked_or_invisible(struct net_device *dev)
-{
-	if (dev->reg_state == NETREG_REGISTERED ||
-	    dev->reg_state == NETREG_UNREGISTERING)
-		netdev_assert_locked(dev);
-}
-
-static inline bool netdev_need_ops_lock(struct net_device *dev)
-{
-	bool ret = dev->request_ops_lock || !!dev->queue_mgmt_ops;
-
-#if IS_ENABLED(CONFIG_NET_SHAPER)
-	ret |= !!dev->netdev_ops->net_shaper_ops;
-#endif
-
-	return ret;
-}
-
-static inline void netdev_lock_ops(struct net_device *dev)
-{
-	if (netdev_need_ops_lock(dev))
-		netdev_lock(dev);
-}
-
-static inline void netdev_unlock_ops(struct net_device *dev)
-{
-	if (netdev_need_ops_lock(dev))
-		netdev_unlock(dev);
-}
-
-static inline void netdev_ops_assert_locked(struct net_device *dev)
-{
-	if (netdev_need_ops_lock(dev))
-		lockdep_assert_held(&dev->lock);
-}
+/* Additional netdev_lock()-related helpers are in net/netdev_lock.h */
 
 void netif_napi_set_irq_locked(struct napi_struct *napi, int irq);
 
diff --git a/include/net/netdev_lock.h b/include/net/netdev_lock.h
new file mode 100644
index 000000000000..99631fbd7f54
--- /dev/null
+++ b/include/net/netdev_lock.h
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _NET_NETDEV_LOCK_H
+#define _NET_NETDEV_LOCK_H
+
+#include <linux/lockdep.h>
+#include <linux/netdevice.h>
+
+static inline bool netdev_trylock(struct net_device *dev)
+{
+	return mutex_trylock(&dev->lock);
+}
+
+static inline void netdev_assert_locked(struct net_device *dev)
+{
+	lockdep_assert_held(&dev->lock);
+}
+
+static inline void netdev_assert_locked_or_invisible(struct net_device *dev)
+{
+	if (dev->reg_state == NETREG_REGISTERED ||
+	    dev->reg_state == NETREG_UNREGISTERING)
+		netdev_assert_locked(dev);
+}
+
+static inline bool netdev_need_ops_lock(struct net_device *dev)
+{
+	bool ret = dev->request_ops_lock || !!dev->queue_mgmt_ops;
+
+#if IS_ENABLED(CONFIG_NET_SHAPER)
+	ret |= !!dev->netdev_ops->net_shaper_ops;
+#endif
+
+	return ret;
+}
+
+static inline void netdev_lock_ops(struct net_device *dev)
+{
+	if (netdev_need_ops_lock(dev))
+		netdev_lock(dev);
+}
+
+static inline void netdev_unlock_ops(struct net_device *dev)
+{
+	if (netdev_need_ops_lock(dev))
+		netdev_unlock(dev);
+}
+
+static inline void netdev_ops_assert_locked(struct net_device *dev)
+{
+	if (netdev_need_ops_lock(dev))
+		lockdep_assert_held(&dev->lock);
+}
+
+static inline int netdev_lock_cmp_fn(const struct lockdep_map *a,
+				     const struct lockdep_map *b)
+{
+	/* Only lower devices currently grab the instance lock, so no
+	 * real ordering issues can occur. In the near future, only
+	 * hardware devices will grab instance lock which also does not
+	 * involve any ordering. Suppress lockdep ordering warnings
+	 * until (if) we start grabbing instance lock on pure SW
+	 * devices (bond/team/veth/etc).
+	 */
+	if (a == b)
+		return 0;
+	return -1;
+}
+
+#define netdev_lockdep_set_classes(dev)				\
+{								\
+	static struct lock_class_key qdisc_tx_busylock_key;	\
+	static struct lock_class_key qdisc_xmit_lock_key;	\
+	static struct lock_class_key dev_addr_list_lock_key;	\
+	static struct lock_class_key dev_instance_lock_key;	\
+	unsigned int i;						\
+								\
+	(dev)->qdisc_tx_busylock = &qdisc_tx_busylock_key;	\
+	lockdep_set_class(&(dev)->addr_list_lock,		\
+			  &dev_addr_list_lock_key);		\
+	lockdep_set_class(&(dev)->lock,				\
+			  &dev_instance_lock_key);		\
+	lock_set_cmp_fn(&dev->lock, netdev_lock_cmp_fn, NULL);	\
+	for (i = 0; i < (dev)->num_tx_queues; i++)		\
+		lockdep_set_class(&(dev)->_tx[i]._xmit_lock,	\
+				  &qdisc_xmit_lock_key);	\
+}
+
+#endif