[PATCH net-next 0/8] net: depend on instance lock for queue related netlink ops

Jakub Kicinski
2025-04-07T19:01:18Z

netdev-genl used to be protected by rtnl_lock. In previous release
we already switched the queue management ops (for Rx zero-copy) to
the instance lock. This series converts other ops to depend on the
instance lock when possible.

Unfortunately queue related state is hard to lock (unlike NAPI)
as the process of switching the number of queues usually involves
a large reconfiguration of the driver. The reconfig process has
historically been under rtnl_lock, but for drivers which opt into
ops locking it is also under the instance lock. Leverage that
and conditionally take rtnl_lock or instance lock depending
on the device capabilities.

Jakub Kicinski (8):
net: avoid potential race between netdev_get_by_index_lock() and netns
switch
net: designate XSK pool pointers in queues as "ops protected"
netdev: add "ops compat locking" helpers
netdev: don't hold rtnl_lock over nl queue info get when possible
xdp: double protect netdev->xdp_flags with netdev->lock
netdev: depend on netdev->lock for xdp features
docs: netdev: break down the instance locking info per ops struct
netdev: depend on netdev->lock for qstats in ops locked drivers

Documentation/networking/netdevices.rst | 61 +++++++++++++----
include/linux/netdevice.h | 7 +-
include/net/netdev_lock.h | 16 +++++
include/net/netdev_queues.h | 4 +-
include/net/netdev_rx_queue.h | 6 +-
include/net/xdp.h | 1 +
net/core/dev.h | 17 ++++-
drivers/net/ethernet/google/gve/gve_main.c | 2 +-
net/core/dev.c | 76 ++++++++++++++++++++--
net/core/lock_debug.c | 2 +-
net/core/netdev-genl.c | 73 ++++++++++-----------
net/core/xdp.c | 12 +++-
net/xdp/xsk.c | 2 +
net/xdp/xsk_buff_pool.c | 7 +-
14 files changed, 220 insertions(+), 66 deletions(-)

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2.49.0