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.

I'm still a bit skeptical about the bonding offloads itself as
mentioned here:

https://lore.kernel.org/all/ZsbkdzvjVf3GiYHa@gauss3.secunet.de/

but I'm OK with this particular pachset.

How should we merge this patchset? It touches several subsystems,
including xfrm. I'm fine merging it through the ipsec-next tree,
but would be also ok if it goes though the net-next tree if
that's easier.