[PATCH net-next 6/6] net: document NETDEV_UNREGISTER unlocked rationale

[Stanislav Fomichev <sdf.kernel@gmail.com>]

The lock-state table marks UNREGISTER as unlocked without saying
why. Add a short note that many handlers release the lowers via
dev_close().

Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
 Documentation/networking/netdevices.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/networking/netdevices.rst b/Documentation/networking/netdevices.rst
index 1bb68a73bb67..761cdb08bf0f 100644
--- a/Documentation/networking/netdevices.rst
+++ b/Documentation/networking/netdevices.rst
@@ -427,6 +427,14 @@ For devices with locked ops, currently only the following notifiers are
 The following notifiers are running without the lock:
 * ``NETDEV_UNREGISTER``
 
+Many ``NETDEV_UNREGISTER`` handlers release their lowers with
+``dev_close()``, which takes the instance lock itself. Holding
+the lock across UNREGISTER would deadlock.
+
+Moving UNREGISTER under the lock is mechanical: switch those
+callers to the ``netif_*()`` lock-held variants. Deferred to
+limit churn.
+
 There are no clear expectations for the remaining notifiers. Notifiers not on
 the list may run with or without the instance lock, potentially even invoking
 the same notifier type with and without the lock from different code paths.
-- 
2.53.0-Meta