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| author |   Jakub Kicinski <kuba@kernel.org> | 2025-05-17 13:08:10 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-05-20 18:14:33 -0700 |
| commit | 4c2bd7913f52b1e5c978edf56cdef39c30a1f603 (patch) | |
| tree | 7864b70108ffdb7a14df74db287aab1962fc2a31 | |
| parent | selftests: net: Fix spellings (diff) | |
| download | wireguard-linux-4c2bd7913f52b1e5c978edf56cdef39c30a1f603.tar.xz wireguard-linux-4c2bd7913f52b1e5c978edf56cdef39c30a1f603.zip | |
net: let lockdep compare instance locks
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>
| -rw-r--r-- | include/net/netdev_lock.h | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/include/net/netdev_lock.h b/include/net/netdev_lock.h index 2a753813f849..c345afecd4c5 100644 --- a/include/net/netdev_lock.h +++ b/include/net/netdev_lock.h @@ -99,16 +99,15 @@ static inline void netdev_unlock_ops_compat(struct net_device *dev) 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; + + /* Allow locking multiple devices only under rtnl_lock, + * the exact order doesn't matter. + * Note that upper devices don't lock their ops, so nesting + * mostly happens in batched device removal for now. + */ + return lockdep_rtnl_is_held() ? -1 : 1; } #define netdev_lockdep_set_classes(dev) \ |