[PATCH net-next v2 0/6] net: devmem: support leased RX and TX queues on netdev unregister

[Mina Almasry <almasrymina@google.com>]

Support leased RX and TX devmem bindings when either the virtual device
(e.g. netkit) or the physical backing net_device is unregistered:

1. Pass struct net_device **dev_ptr to net_devmem_lock_dev() so callers
   can lock either binding->map_dev or binding->bind_dev.
2. Rename binding->dev and binding->vdev to binding->map_dev (physical
   DMA device) and binding->bind_dev (device passed to bind-rx/bind-tx).
3. Guard __netif_mp_open_rxq() and __netif_mp_close_rxq() against an
   unregistering physical device reached through a queue lease.
4. Always populate bind_dev on RX and TX bindings and handle teardown
   and netdev unregistration of both bind_dev and map_dev.
5. Resolve the physical backing map_dev in netdev_nl_get_dma_dev() for
   leased RX bindings, lock map_dev around net_devmem_bind_dmabuf() on
   bind-rx when map_dev differs from netdev, assert both devices are
   locked, and check map_dev->reg_state.
6. Add kselftests in nl_netdev.py covering leased RX and TX devmem
   bindings across both virtual-first and physical-first netdev
   unregistration orders.

v2:
- Split patch 3/4 from v1 into 3 smaller commits (patches 3/6..5/6).
- Clear rxq->mp_params and return 0 in __netif_mp_close_rxq() whenever
  dev is already unregistering, avoiding queue reconfiguration on an
  already-shut-down map_dev during cascaded lease teardown (Sashiko).
- Drop unnecessary xa_erase() in net_devmem_unbind_dmabuf() and use a
  local map_dev variable in net_devmem_get_binding() (Stanislav).
- Restore ASSERT_EXCLUSIVE_WRITER(binding->bind_dev) in
  mp_dmabuf_devmem_uninstall(), drop redundant bind_dev->reg_state check
  in net_devmem_bind_dmabuf(), and expand commit message rationale
  (Dragos, Stanislav).
- v1: https://lore.kernel.org/netdev/20261103232659.1340283-1-almasrymina@google.com/


Mina Almasry (6):
  net: devmem: pass net_device pointer to net_devmem_lock_dev()
  net: devmem: rename binding dev and vdev to map_dev and bind_dev
  net: guard memory provider RX queue open and close on unregister
  net: devmem: always populate bind_dev and detach both devices on
    unregister
  net: devmem: resolve physical map_dev for leased RX bindings
  selftests: net: add leased devmem RX and TX netdev unregister tests

 net/core/dev.c                           |   2 +-
 net/core/devmem.c                        | 110 ++++++++++---------
 net/core/devmem.h                        |  25 +++--
 net/core/netdev-genl.c                   |  58 ++++++----
 net/core/netdev_rx_queue.c               |  17 ++-
 tools/testing/selftests/net/nl_netdev.py | 132 ++++++++++++++++++++++-
 6 files changed, 253 insertions(+), 91 deletions(-)


base-commit: fa5196392691051963726787944db872420dfa75
-- 
2.56.0.455.g6c5a503b38-goog