Re: [PATCH net-next v2] net: convert netdev_nl_sock bindings list to xarray

[Jakub Kicinski <kuba@kernel.org>]

On Fri, 14 Aug 2026 12:04:59 +0530 Shivaji Kant wrote:
> I understand, my thinking for this was removing priv->lock is more
> than just simplification, it can be a concurrency win. Sorry for not
> making it more explicit in the patch description.
> As you pointed out, priv->lock current serializes the entire doit
> block (including netdev_get_by_index_lock() and the entire
> net_devmem_bind_dmabuf_to_queue() loop). Furthermore,
> net_devmem_unbind_dmabuf() blocks on synchronize_net(). With the
> current mutex implementation, if one thread is destroying a socket or
> unbinding a dmabuf, it holds priv->lock across synchronize_net(),
> completely blocking any concurrent netlink commands on the same socket
> (e.g., binding to a different queue/interface).
> Converting to an xarray allows us to cleanly dissolve this wide
> serialization scope. xa_for_each() handles the RCU grace periods
> internally without holding a manual lock across synchronize_net(). I
> agree the changelog must be updated to clearly state that reducing
> this serialization scope is the explicit goal.

If it's an optimization you have to show prod data (as in not a micro
benchmark) that the problem actually exists.

And please describe how your application manages the sockets, we're
talking about a lock on a management socket, not some global lock
blocking the whole system.