RE: [Intel-wired-lan] [PATCH net-next v2 03/13] net: introduce ndo_set_rx_mode_async and dev_rx_mode_work

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf
> Of Stanislav Fomichev
> Sent: Wednesday, March 18, 2026 4:03 PM
> To: netdev@xxxxxxxxxxxxxxx
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> Subject: [Intel-wired-lan] [PATCH net-next v2 03/13] net: introduce
> ndo_set_rx_mode_async and dev_rx_mode_work
> 
> Add ndo_set_rx_mode_async callback that drivers can implement instead
> of the legacy ndo_set_rx_mode. The legacy callback runs under the
> netif_addr_lock spinlock with BHs disabled, preventing drivers from
> sleeping. The async variant runs from a work queue with rtnl_lock and
> netdev_lock_ops held, in fully sleepable context.
> 
> When __dev_set_rx_mode() sees ndo_set_rx_mode_async, it schedules
> dev_rx_mode_work instead of calling the driver inline. The work
> function takes two snapshots of each address list (uc/mc) under the
> addr_lock, then drops the lock and calls the driver with the work
> copies. After the driver returns, it reconciles the snapshots back to
> the real lists under the lock.
> 
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>
> ---
>  Documentation/networking/netdevices.rst |  8 +++
>  include/linux/netdevice.h               | 20 ++++++
>  net/core/dev.c                          | 94 +++++++++++++++++++++++-
> -
>  3 files changed, 115 insertions(+), 7 deletions(-)
> 
> diff --git a/Documentation/networking/netdevices.rst
> b/Documentation/networking/netdevices.rst
> index 35704d115312..dc83d78d3b27 100644
> --- a/Documentation/networking/netdevices.rst
> +++ b/Documentation/networking/netdevices.rst
> @@ -289,6 +289,14 @@ struct net_device synchronization rules
>  ndo_set_rx_mode:
>  	Synchronization: netif_addr_lock spinlock.
>  	Context: BHs disabled


...

> 
> -/*
> - *	Upload unicast and multicast address lists to device and
> - *	configure RX filtering. When the device doesn't support unicast
> - *	filtering it is put in promiscuous mode while unicast addresses
> - *	are present.
> +static void dev_rx_mode_work(struct work_struct *work) {
> +	struct net_device *dev = container_of(work, struct net_device,
> +					      rx_mode_work);
> +	struct netdev_hw_addr_list uc_snap, mc_snap, uc_ref, mc_ref;
> +	const struct net_device_ops *ops = dev->netdev_ops;
> +	int err;
> +
> +	__hw_addr_init(&uc_snap);
> +	__hw_addr_init(&mc_snap);
> +	__hw_addr_init(&uc_ref);
> +	__hw_addr_init(&mc_ref);
> +
> +	rtnl_lock();
> +	netdev_lock_ops(dev);
> +
> +	if (!netif_up_and_present(dev))
> +		goto out;
> +
> +	if (ops->ndo_set_rx_mode_async) {
> +		netif_addr_lock_bh(dev);
> +
> +		err = __hw_addr_list_snapshot(&uc_snap, &dev->uc,
> +					      dev->addr_len);
> +		if (!err)
> +			err = __hw_addr_list_snapshot(&uc_ref, &dev->uc,
> +						      dev->addr_len);
> +		if (!err)
> +			err = __hw_addr_list_snapshot(&mc_snap, &dev->mc,
> +						      dev->addr_len);
> +		if (!err)
> +			err = __hw_addr_list_snapshot(&mc_ref, &dev->mc,
> +						      dev->addr_len);
> +		netif_addr_unlock_bh(dev);
> +
> +		if (err) {
> +			__hw_addr_flush(&uc_snap);
> +			__hw_addr_flush(&uc_ref);
> +			__hw_addr_flush(&mc_snap);
Shouldn't here go cleanup for symmetry? 
			__hw_addr_flush(&mc_ref);

> +			goto out;
> +		}
> +
> +		ops->ndo_set_rx_mode_async(dev, &uc_snap, &mc_snap);
> +
> +		netif_addr_lock_bh(dev);
> +		__hw_addr_list_reconcile(&dev->uc, &uc_snap,
> +					 &uc_ref, dev->addr_len);
> +		__hw_addr_list_reconcile(&dev->mc, &mc_snap,
> +					 &mc_ref, dev->addr_len);
> +		netif_addr_unlock_bh(dev);
> +	}
> +
> +out:
> +	netdev_unlock_ops(dev);
> +	rtnl_unlock();
> +}

...

> --
> 2.53.0