[net-next,v2,00/11] net: Hold netdev instance lock during ndo operations

Message

Stanislav Fomichev Feb. 14, 2025, 3:34 p.m. UTC

As the gradual purging of rtnl continues, start grabbing netdev
instance lock in more places so we can get to the state where
most paths are working without rtnl. Start with requiring the
drivers that use shaper api (and later queue mgmt api) to work
with both rtnl and netdev instance lock. Eventually we might
attempt to drop rtnl. This mostly affects iavf, gve, bnxt and
netdev sim (as the drivers that implement shaper/queue mgmt)
so those drivers are converted in the process.

call_netdevice_notifiers locking is very inconsistent and might need
a separate follow up. Some notified events are covered by the
instance lock, some are not, which might complicate the driver
expectations.

Changes since v1:
- fix netdev_set_mtu_ext_locked in the wrong place ([e-mail])
- add missing depend on CONFIG_NET_SHAPER for dummy device
  ([e-mail])
  - not sure we need to apply dummy device patch..
- need_netdev_ops_lock -> netdev_need_ops_lock (Jakub)
- remove netdev_assert_locked near napi_xxx_locked calls (Jakub)
- fix netdev_lock_cmp_fn comment and line length (Jakub)
- fix kdoc style of dev_api.c routines (Jakub)
- reflow dev_setup_tc to avoid indent (Jakub)
- keep tc_can_offload checks outside of dev_setup_tc (Jakub)

Changes since RFC:
- other control paths are protected
- bntx has been converted to mostly depend on netdev instance lock

Cc: Saeed Mahameed <[e-mail]>

Jakub Kicinski (1):
  net: ethtool: try to protect all callback with netdev instance lock

Stanislav Fomichev (10):
  net: hold netdev instance lock during ndo_open/ndo_stop
  net: hold netdev instance lock during ndo_setup_tc
  net: hold netdev instance lock during queue operations
  net: hold netdev instance lock during rtnetlink operations
  net: hold netdev instance lock during ioctl operations
  net: hold netdev instance lock during sysfs operations
  net: hold netdev instance lock during ndo_bpf
  net: dummy: add dummy shaper API
  docs: net: document new locking reality
  eth: bnxt: remove most dependencies on RTNL

 Documentation/networking/netdevices.rst       |  57 ++-
 drivers/net/Kconfig                           |   1 +
 drivers/net/bonding/bond_main.c               |  16 +-
 drivers/net/dummy.c                           |  37 ++
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     | 132 +++----
 .../net/ethernet/broadcom/bnxt/bnxt_devlink.c |   9 +
 .../net/ethernet/broadcom/bnxt/bnxt_sriov.c   |   6 +
 drivers/net/ethernet/broadcom/bnxt/bnxt_ulp.c |  16 +-
 drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c |  18 +-
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c |   3 +-
 drivers/net/ethernet/google/gve/gve_main.c    |   8 +-
 drivers/net/ethernet/google/gve/gve_utils.c   |   6 +-
 drivers/net/ethernet/intel/iavf/iavf_main.c   |  16 +-
 drivers/net/netdevsim/ethtool.c               |   2 -
 drivers/net/netdevsim/netdev.c                |  36 +-
 include/linux/netdevice.h                     |  63 +++-
 kernel/bpf/offload.c                          |   7 +-
 net/8021q/vlan_dev.c                          |   4 +-
 net/core/Makefile                             |   2 +-
 net/core/dev.c                                | 254 +++++---------
 net/core/dev.h                                |  19 +-
 net/core/dev_api.c                            | 331 ++++++++++++++++++
 net/core/dev_ioctl.c                          |  67 ++--
 net/core/net-sysfs.c                          |   2 +
 net/core/netdev_rx_queue.c                    |   5 +
 net/core/rtnetlink.c                          |  47 ++-
 net/dsa/conduit.c                             |  16 +-
 net/dsa/user.c                                |   5 +-
 net/ethtool/cabletest.c                       |  20 +-
 net/ethtool/features.c                        |   6 +-
 net/ethtool/ioctl.c                           |   6 +
 net/ethtool/module.c                          |   8 +-
 net/ethtool/netlink.c                         |  12 +
 net/ethtool/phy.c                             |  20 +-
 net/ethtool/rss.c                             |   2 +
 net/ethtool/tsinfo.c                          |   9 +-
 net/netfilter/nf_flow_table_offload.c         |   2 +-
 net/netfilter/nf_tables_offload.c             |   2 +-
 net/sched/cls_api.c                           |   2 +-
 net/sched/sch_api.c                           |   8 +-
 net/sched/sch_cbs.c                           |   8 +-
 net/sched/sch_etf.c                           |   8 +-
 net/sched/sch_ets.c                           |   4 +-
 net/sched/sch_fifo.c                          |   4 +-
 net/sched/sch_gred.c                          |   2 +-
 net/sched/sch_htb.c                           |   2 +-
 net/sched/sch_mq.c                            |   2 +-
 net/sched/sch_mqprio.c                        |   6 +-
 net/sched/sch_prio.c                          |   2 +-
 net/sched/sch_red.c                           |   5 +-
 net/sched/sch_taprio.c                        |  17 +-
 net/sched/sch_tbf.c                           |   4 +-
 net/xdp/xsk.c                                 |   3 +
 net/xdp/xsk_buff_pool.c                       |   2 +
 54 files changed, 923 insertions(+), 428 deletions(-)
 create mode 100644 net/core/dev_api.c

Comments

Jakub Kicinski Feb. 15, 2025, 3:55 p.m. UTC | #1

On Fri, 14 Feb 2025 07:34:29 -0800 Stanislav Fomichev wrote:
> As the gradual purging of rtnl continues, start grabbing netdev
> instance lock in more places so we can get to the state where
> most paths are working without rtnl. Start with requiring the
> drivers that use shaper api (and later queue mgmt api) to work
> with both rtnl and netdev instance lock. Eventually we might
> attempt to drop rtnl. This mostly affects iavf, gve, bnxt and
> netdev sim (as the drivers that implement shaper/queue mgmt)
> so those drivers are converted in the process.
> 
> call_netdevice_notifiers locking is very inconsistent and might need
> a separate follow up. Some notified events are covered by the
> instance lock, some are not, which might complicate the driver
> expectations.

Appears to break the CI build:

net/core/dev.c:11392:12: error: ‘netdev_lock_cmp_fn’ defined but not used [-Werror=unused-function]
11392 | static int netdev_lock_cmp_fn(const struct lockdep_map *a,
      |            ^~~~~~~~~~~~~~~~~~