Re: [PATCH net-next 3/3] net/mlx5: Apply devlink default eswitch mode during init

[Mark Bloch <mbloch@nvidia.com>]

On 26/05/2026 10:44, Jiri Pirko wrote:
> Thu, May 21, 2026 at 09:24:34AM +0200, tariqt@nvidia.com wrote:
>> From: Mark Bloch <mbloch@nvidia.com>
>>
>> Apply devlink default eswitch mode for mlx5 devices after successful
>> device initialization while holding the devlink instance lock.
>>
>> At this point the devlink instance is registered and the mlx5 devlink
>> operations are available, so the default eswitch mode can be applied to
>> the matching PCI devlink handle.
>>
>> Signed-off-by: Mark Bloch <mbloch@nvidia.com>
>> Reviewed-by: Shay Drori <shayd@nvidia.com>
>> Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
>> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
>> ---
>> drivers/net/ethernet/mellanox/mlx5/core/main.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
>> index 0c6e4efe38c8..4528097f3d84 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
>> @@ -1391,6 +1391,21 @@ static void mlx5_unload(struct mlx5_core_dev *dev)
>> 	mlx5_free_bfreg(dev, &dev->priv.bfreg);
>> }
>>
>> +static void mlx5_devl_apply_default_esw_mode(struct mlx5_core_dev *dev)
>> +{
>> +	struct devlink *devlink = priv_to_devlink(dev);
>> +	int err;
>> +
>> +	if (!MLX5_ESWITCH_MANAGER(dev))
>> +		return;
>> +
>> +	devl_assert_locked(devlink);
>> +	err = devl_apply_default_esw_mode(devlink);
>> +	if (err)
>> +		mlx5_core_warn(dev, "Couldn't apply default eswitch mode, err %d\n",
>> +			       err);
>> +}
>> +
>> int mlx5_init_one_devl_locked(struct mlx5_core_dev *dev)
>> {
>> 	bool light_probe = mlx5_dev_is_lightweight(dev);
>> @@ -1437,6 +1452,7 @@ int mlx5_init_one_devl_locked(struct mlx5_core_dev *dev)
>> 		mlx5_core_err(dev, "mlx5_hwmon_dev_register failed with error code %d\n", err);
>>
>> 	mutex_unlock(&dev->intf_state_mutex);
>> +	mlx5_devl_apply_default_esw_mode(dev);
> 
> I wonder how we can make this work for all. I mean, other driver would
> silently ignore this command like arg, right? Any idea how to make all
> drivers follow the arg from very beginning?
> 

I have a follow-up series that adds the call to all drivers which support
setting eswitch mode. When going over the other drivers, what I found is
that the right point to apply the default is driver specific, drivers
I have patch for:

46e16c6d9836 net: Apply devlink esw mode defaults
ab4f54102ba9 bnxt_en: Apply devlink default eswitch mode during init
b48cce1607bb liquidio: Apply devlink default eswitch mode during init
4ea54b0fe04a ice: Apply devlink default eswitch mode during init
b7faddaa1c90 octeontx2-af: Apply devlink default eswitch mode during init
74b0c22c47b9 octeontx2-pf: Apply devlink default eswitch mode during init
5000e4c3d768 nfp: Apply devlink default eswitch mode during init
97a218e95e41 netdevsim: Apply devlink default eswitch mode during init

I don't think doing this generically from devlink is realistic. devlink
doesn't really know when a given driver is ready to change eswitch mode.
Some drivers need SR-IOV state, representor setup, or other init pieces to
be ready first, and the locking is not identical across drivers either.

Also, since this knob is only about eswitch mode, I don't think we need to
touch every devlink driver. Drivers that don't implement eswitch_mode_set()
would just ignore it anyway. The follow-up only wires the default into
drivers that actually support changing eswitch mode.

Mark

> 
>> 	return 0;
>>
>> err_register:
>> @@ -1538,6 +1554,7 @@ int mlx5_load_one_devl_locked(struct mlx5_core_dev *dev, bool recovery)
>> 		goto err_attach;
>>
>> 	mutex_unlock(&dev->intf_state_mutex);
>> +	mlx5_devl_apply_default_esw_mode(dev);
>> 	return 0;
>>
>> err_attach:
>> -- 
>> 2.44.0
>>