Re: [PATCH net-next v3 0/6] xfrm & bonding: Correct use of xso.real_dev

[Steffen Klassert <steffen.klassert@secunet.com>]

On Fri, Apr 11, 2025 at 10:49:52AM +0300, Cosmin Ratiu wrote:
> This patch series was motivated by fixing a few bugs in the bonding
> driver related to xfrm state migration on device failover.
> 
> struct xfrm_dev_offload has two net_device pointers: dev and real_dev.
> The first one is the device the xfrm_state is offloaded on and the
> second one is used by the bonding driver to manage the underlying device
> xfrm_states are actually offloaded on. When bonding isn't used, the two
> pointers are the same.
> 
> This causes confusion in drivers: Which device pointer should they use?
> If they want to support bonding, they need to only use real_dev and
> never look at dev.
> 
> Furthermore, real_dev is used without proper locking from multiple code
> paths and changing it is dangerous. See commit [1] for example.
> 
> This patch series clears things out by removing all uses of real_dev
> from outside the bonding driver.
> Then, the bonding driver is refactored to fix a couple of long standing
> races and the original bug which motivated this patch series.
> 
> [1] commit f8cde9805981 ("bonding: fix xfrm real_dev null pointer
> dereference")
> 
> v2 -> v3:
> Added a comment with locking expectations for real_dev.
> Removed unnecessary bond variable from bond_ipsec_del_sa().
> v1 -> v2:
> Added missing kdoc for various functions.
> Made bond_ipsec_del_sa() use xso.real_dev instead of curr_active_slave.
> 
> Cosmin Ratiu (6):
> Cleaning up unnecessary uses of xso.real_dev:
>   net/mlx5: Avoid using xso.real_dev unnecessarily
>   xfrm: Use xdo.dev instead of xdo.real_dev
>   xfrm: Remove unneeded device check from validate_xmit_xfrm
> Refactoring device operations to get an explicit device pointer:
>   xfrm: Add explicit dev to .xdo_dev_state_{add,delete,free}
> Fixing a bonding xfrm state migration bug:
>   bonding: Mark active offloaded xfrm_states
> Fixing long standing races in bonding:
>   bonding: Fix multiple long standing offload races
> 
>  Documentation/networking/xfrm_device.rst      |  10 +-
>  drivers/net/bonding/bond_main.c               | 119 +++++++++---------
>  .../net/ethernet/chelsio/cxgb4/cxgb4_main.c   |  20 +--
>  .../inline_crypto/ch_ipsec/chcr_ipsec.c       |  18 ++-
>  .../net/ethernet/intel/ixgbe/ixgbe_ipsec.c    |  41 +++---
>  drivers/net/ethernet/intel/ixgbevf/ipsec.c    |  21 ++--
>  .../marvell/octeontx2/nic/cn10k_ipsec.c       |  18 +--
>  .../mellanox/mlx5/core/en_accel/ipsec.c       |  28 ++---
>  .../mellanox/mlx5/core/en_accel/ipsec.h       |   1 +
>  .../net/ethernet/netronome/nfp/crypto/ipsec.c |  11 +-
>  drivers/net/netdevsim/ipsec.c                 |  15 ++-
>  include/linux/netdevice.h                     |  10 +-
>  include/net/xfrm.h                            |  11 ++
>  net/xfrm/xfrm_device.c                        |  13 +-
>  net/xfrm/xfrm_state.c                         |  16 +--
>  15 files changed, 185 insertions(+), 167 deletions(-)

Series applied to ipsec-next, thanks a lot Cosmin!