Re: [PATCH net-next 02/11] net: add helpers for lookup and walking netdevs under netdev_lock()

[Joe Damato <jdamato@fastly.com>]

On Mon, Jan 13, 2025 at 07:51:08PM -0800, Jakub Kicinski wrote:
> Add helpers for accessing netdevs under netdev_lock().
> There's some careful handling needed to find the device and lock it
> safely, without it getting unregistered, and without taking rtnl_lock
> (the latter being the whole point of the new locking, after all).
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  net/core/dev.h |  16 +++++++
>  net/core/dev.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 126 insertions(+)

[...]

> diff --git a/net/core/dev.c b/net/core/dev.c
> index fda4e1039bf0..5c1e71afbe1c 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -783,6 +783,49 @@ struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id)
>  	return napi;
>  }

[...]

> +
> +struct net_device *
> +netdev_xa_find_lock(struct net *net, struct net_device *dev,
> +		    unsigned long *index)

Minor nit, the other added helper functions have docs, but (unless I
missed it somewhere) this one doesn't. Maybe worthwhile to add
docs if sending a v2, but probably not worth a re-roll just for
this.