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path: root/include/net/netdev_lock.h
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2025-05-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.15-rc8). Conflicts: 80f2ab46c2ee ("irdma: free iwdev->rf after removing MSI-X") 4bcc063939a5 ("ice, irdma: fix an off by one in error handling code") c24a65b6a27c ("iidc/ice/irdma: Update IDC to support multiple consumers") https://lore.kernel.org/20250513130630.280ee6c5@canb.auug.org.au No extra adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20bnxt_en: Fix netdev locking in ULP IRQ functionsMichael Chan
netdev_lock is already held when calling bnxt_ulp_irq_stop() and bnxt_ulp_irq_restart(). When converting rtnl_lock to netdev_lock, the original code was rtnl_dereference() to indicate that rtnl_lock was already held. rcu_dereference_protected() is the correct conversion after replacing rtnl_lock with netdev_lock. Add a new helper netdev_lock_dereference() similar to rtnl_dereference(). Fixes: 004b5008016a ("eth: bnxt: remove most dependencies on RTNL") Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com> Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com> Signed-off-by: Michael Chan <michael.chan@broadcom.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://patch.msgid.link/20250519204130.3097027-2-michael.chan@broadcom.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-05-20net: let lockdep compare instance locksJakub Kicinski
AFAIU always returning -1 from lockdep's compare function basically disables checking of dependencies between given locks. Try to be a little more precise about what guarantees that instance locks won't deadlock. Right now we only nest them under protection of rtnl_lock. Mostly in unregister_netdevice_many() and dev_close_many(). Acked-by: Stanislav Fomichev <sdf@fomichev.me> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://patch.msgid.link/20250517200810.466531-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-17netdev: fix the locking for netdev notificationsJakub Kicinski
Kuniyuki reports that the assert for netdev lock fires when there are netdev event listeners (otherwise we skip the netlink event generation). Correct the locking when coming from the notifier. The NETDEV_XDP_FEAT_CHANGE notifier is already fully locked, it's the documentation that's incorrect. Fixes: 99e44f39a8f7 ("netdev: depend on netdev->lock for xdp features") Reported-by: syzkaller <syzkaller@googlegroups.com> Reported-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/20250410171019.62128-1-kuniyu@amazon.com Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250416030447.1077551-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-09netdev: add "ops compat locking" helpersJakub Kicinski
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>
2025-04-03netdevsim: add dummy device notifiersStanislav Fomichev
In order to exercise and verify notifiers' locking assumptions, register dummy notifiers (via register_netdevice_notifier_dev_net). Share notifier event handler that enforces the assumptions with lock_debug.c (rename and export rtnl_net_debug_event as netdev_debug_event). Add ops lock asserts to netdev_debug_event. Signed-off-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250401163452.622454-6-sdf@fomichev.me Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25net: designate queue -> napi linking as "ops protected"Jakub Kicinski
netdev netlink is the only reader of netdev_{,rx_}queue->napi, and it already holds netdev->lock. Switch protection of the writes to netdev->lock to "ops protected". The expectation will be now that accessing queue->napi will require netdev->lock for "ops locked" drivers, and rtnl_lock for all other drivers. Current "ops locked" drivers don't require any changes. gve and netdevsim use _locked() helpers right next to netif_queue_set_napi() so they must be holding the instance lock. iavf doesn't call it. bnxt is a bit messy but all paths seem locked. Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250324224537.248800-7-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25net: explain "protection types" for the instance lockJakub Kicinski
Try to define some terminology for which fields are protected by which lock and how. Some fields are protected by both rtnl_lock and instance lock which is hard to talk about without having a "key phrase" to refer to a particular protection scheme. "ops protected" fields are defined later in the series, one by one. Add ASSERT_RTNL() to netdev_ops_assert_locked() for drivers not other instance protection of ops. Hopefully it's not too confusion that netdev_lock_ops() does not match the lock which netdev_ops_assert_locked() will assert, exactly. The noun "ops" is in a different place in the name, so I think it's acceptable... Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250324224537.248800-5-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-25net: constify dev pointer in misc instance lock helpersJakub Kicinski
lockdep asserts and predicates can operate on const pointers. In the future this will let us add asserts in functions which operate on const pointers like dev_get_min_mp_channel_count(). Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://patch.msgid.link/20250324224537.248800-4-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-03-08net: move misc netdev_lock flavors to a separate headerJakub Kicinski
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>