netdev: define NETDEV_INTERNAL

JIRA: https://issues.redhat.com/browse/RHEL-127480

commit 0b7bdc7
Author: Jakub Kicinski <kuba@kernel.org>
Date:   Tue Jan 7 08:08:40 2025 -0800

    netdev: define NETDEV_INTERNAL

    Linus suggested during one of past maintainer summits (in context of
    a DMA_BUF discussion) that symbol namespaces can be used to prevent
    unwelcome but in-tree code from using all exported functions.
    Create a namespace for netdev.

    Export netdev_rx_queue_restart(), drivers may want to use it since
    it gives them a simple and safe way to restart a queue to apply
    config changes. But it's both too low level and too actively developed
    to be used outside netdev.

    Reviewed-by: Willem de Bruijn <willemb@google.com>
    Reviewed-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>

Author: michich

Documentation/networking/netdevices.rst

@@ -297,3 +297,13 @@ napi->poll:
 	Context:
 		 softirq
 		 will be called with interrupts disabled by netconsole.
+
+NETDEV_INTERNAL symbol namespace
+================================
+
+Symbols exported as NETDEV_INTERNAL can only be used in networking
+core and drivers which exclusively flow via the main networking list and trees.
+Note that the inverse is not true, most symbols outside of NETDEV_INTERNAL
+are not expected to be used by random code outside netdev either.
+Symbols may lack the designation because they predate the namespaces,
+or simply due to an oversight.

net/core/netdev_rx_queue.c

@@ -79,3 +79,4 @@ int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
 
 	return err;
 }
+EXPORT_SYMBOL_NS_GPL(netdev_rx_queue_restart, "NETDEV_INTERNAL");