Re: [PATCH net v2 0/4] net: devmem: fix RX and TX binding teardown on device unregistration

[Dragos Tatulea <dtatulea@nvidia.com>]

On 12.10.26 19:42, Mina Almasry wrote:
> Fix two device-unregistration lifecycle bugs in devmem TCP bindings and
> add netdevsim support plus selftests covering both RX and TX device
> unregistration:
> 
> 1. net: devmem: unmap dma_buf synchronously on queue uninstall
>    Synchronously unmap and detach binding->attachment under binding->lock
>    when the last RX queue is uninstalled in mp_dmabuf_devmem_uninstall(),
>    and unmap RX bindings that were already unbound on NETDEV_UNREGISTER,
>    preventing slab-use-after-free in dma_unmap_sg_attrs() when the binding
>    is freed after dma_dev.
> 
> 2. net: devmem: detach TX bindings on NETDEV_UNREGISTER
>    Extend net_devmem_dev_unregister() to fully detach and unmap TX
>    bindings when binding->dev unregisters, or clear binding->vdev alone
>    when only a virtual device unregisters while binding->dev lives.
> 
> 3. netdevsim: support devmem RX and TX bindings
>    Enable PP_FLAG_DMA_MAP | PP_FLAG_ALLOW_UNREADABLE_NETMEM, 64-bit DMA mask
>    on nsim_bus_dev, and NETMEM_TX_DMA on netdevsim so devmem RX/TX bindings
>    can be exercised in software selftests.
> 
> 4. selftests: net: add devmem RX and TX netdev unregister tests
>    Add devmem_bind_rx_unregister_check and devmem_bind_tx_unregister_check
>    to tools/testing/selftests/net/nl_netdev.py.
> 
> Cc: Tariq Toukan <tariqt@nvidia.com>
> Cc: Kaifeng Wang <kaifengw@google.com>
> 
> ---
> v2:
> - 1/4: Don't unmap when a leased queue is unleased. Keep bindings in
>   net_devmem_dmabuf_bindings until freed, hidden from TX lookups by an
>   xarray mark, and unmap unbound RX bindings on NETDEV_UNREGISTER. Update
>   the binding->lock and binding->ref comments. (Sashiko)
> - 2/4: Detach TX bindings from the same net_devmem_lock-protected walk,
>   which now also covers unbound TX bindings, and clear the LIVE mark
>   instead of erasing the ID. The walk no longer uses RCU or takes
>   binding references (Stanislav).
> - Link to v1: https://lore.kernel.org/netdev/20261010025532.839559-1-almasrymina@google.com/
> 
> Mina Almasry (4):
>   net: devmem: unmap dma_buf synchronously on queue uninstall
>   net: devmem: detach TX bindings on NETDEV_UNREGISTER
>   netdevsim: support devmem RX and TX bindings
>   selftests: net: add devmem RX and TX netdev unregister tests
> 
>  drivers/net/netdevsim/bus.c              |   1 +
>  drivers/net/netdevsim/netdev.c           |  21 ++--
>  net/core/devmem.c                        | 121 ++++++++++++++++++++---
>  net/core/devmem.h                        |  10 +-
>  net/core/netdev-genl.c                   |   1 +
>  tools/testing/selftests/net/nl_netdev.py | 108 +++++++++++++++++++-
>  6 files changed, 236 insertions(+), 26 deletions(-)
> 
> 
> base-commit: 4f6ac74fa594a918d41255c941256e1d51592d3b

Went through the series and it looks good to my feeble human brain:

Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>

I am biased though because I need Mina's code to add support for
unbinding the dma device for data-direct.

Thanks,
Dragos