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4ec9031cbe
Add helpers to "lock a netdev in a backward-compatible way", which for ops-locked netdevs will mean take the instance lock. For drivers which haven't opted into the ops locking we'll take rtnl_lock. The scoped foreach is dropping and re-taking the lock for each device, even if prev and next are both under rtnl_lock. I hope that's fine since we expect that netdev nl to be mostly supported by modern drivers, and modern drivers should also opt into the instance locking. Note that these helpers are mostly needed for queue related state, because drivers modify queue config in their ops in a non-atomic way. Or differently put, queue changes don't have a clear-cut API like NAPI configuration. Any state that can should just use the instance lock directly, not the "compat" hacks. Reviewed-by: Joe Damato <jdamato@fastly.com> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250408195956.412733-4-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
121 lines
3.0 KiB
C
121 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#ifndef _NET_NETDEV_LOCK_H
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#define _NET_NETDEV_LOCK_H
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#include <linux/lockdep.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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static inline bool netdev_trylock(struct net_device *dev)
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{
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return mutex_trylock(&dev->lock);
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}
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static inline void netdev_assert_locked(const struct net_device *dev)
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{
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lockdep_assert_held(&dev->lock);
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}
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static inline void
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netdev_assert_locked_or_invisible(const struct net_device *dev)
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{
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if (dev->reg_state == NETREG_REGISTERED ||
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dev->reg_state == NETREG_UNREGISTERING)
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netdev_assert_locked(dev);
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}
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static inline bool netdev_need_ops_lock(const struct net_device *dev)
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{
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bool ret = dev->request_ops_lock || !!dev->queue_mgmt_ops;
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#if IS_ENABLED(CONFIG_NET_SHAPER)
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ret |= !!dev->netdev_ops->net_shaper_ops;
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#endif
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return ret;
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}
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static inline void netdev_lock_ops(struct net_device *dev)
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{
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if (netdev_need_ops_lock(dev))
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netdev_lock(dev);
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}
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static inline void netdev_unlock_ops(struct net_device *dev)
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{
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if (netdev_need_ops_lock(dev))
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netdev_unlock(dev);
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}
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static inline void netdev_ops_assert_locked(const struct net_device *dev)
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{
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if (netdev_need_ops_lock(dev))
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lockdep_assert_held(&dev->lock);
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else
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ASSERT_RTNL();
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}
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static inline void
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netdev_ops_assert_locked_or_invisible(const struct net_device *dev)
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{
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if (dev->reg_state == NETREG_REGISTERED ||
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dev->reg_state == NETREG_UNREGISTERING)
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netdev_ops_assert_locked(dev);
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}
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static inline void netdev_lock_ops_compat(struct net_device *dev)
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{
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if (netdev_need_ops_lock(dev))
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netdev_lock(dev);
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else
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rtnl_lock();
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}
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static inline void netdev_unlock_ops_compat(struct net_device *dev)
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{
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if (netdev_need_ops_lock(dev))
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netdev_unlock(dev);
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else
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rtnl_unlock();
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}
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static inline int netdev_lock_cmp_fn(const struct lockdep_map *a,
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const struct lockdep_map *b)
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{
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/* Only lower devices currently grab the instance lock, so no
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* real ordering issues can occur. In the near future, only
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* hardware devices will grab instance lock which also does not
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* involve any ordering. Suppress lockdep ordering warnings
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* until (if) we start grabbing instance lock on pure SW
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* devices (bond/team/veth/etc).
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*/
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if (a == b)
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return 0;
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return -1;
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}
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#define netdev_lockdep_set_classes(dev) \
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{ \
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static struct lock_class_key qdisc_tx_busylock_key; \
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static struct lock_class_key qdisc_xmit_lock_key; \
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static struct lock_class_key dev_addr_list_lock_key; \
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static struct lock_class_key dev_instance_lock_key; \
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unsigned int i; \
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\
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(dev)->qdisc_tx_busylock = &qdisc_tx_busylock_key; \
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lockdep_set_class(&(dev)->addr_list_lock, \
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&dev_addr_list_lock_key); \
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lockdep_set_class(&(dev)->lock, \
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&dev_instance_lock_key); \
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lock_set_cmp_fn(&dev->lock, netdev_lock_cmp_fn, NULL); \
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for (i = 0; i < (dev)->num_tx_queues; i++) \
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lockdep_set_class(&(dev)->_tx[i]._xmit_lock, \
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&qdisc_xmit_lock_key); \
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}
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int netdev_debug_event(struct notifier_block *nb, unsigned long event,
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void *ptr);
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#endif
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