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Calling devl_apply_default_esw_mode() also clears >>>> any pending default apply work queued by devl_register(), so the queued >>>> work will not apply the same default again. >>>> >>>> Keep this call in mlx5_init_one() rather than the lower-level >>>> devl-locked init helper. That helper is also used by devlink reload, and >>>> devlink core already applies the boot default after a successful >>>> DRIVER_REINIT reload. >>>> >>>> Signed-off-by: Mark Bloch >>>> --- >>>> drivers/net/ethernet/mellanox/mlx5/core/main.c | 13 +++++++++++++ >>>> 1 file changed, 13 insertions(+) >>>> >>>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c >>>> index 643b4aac2033..0712efea74cc 100644 >>>> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c >>>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c >>>> @@ -1392,6 +1392,17 @@ 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); >>>> + >>>> + if (!MLX5_ESWITCH_MANAGER(dev)) >>>> + return; >>>> + >>>> + devl_assert_locked(devlink); >>>> + devl_apply_default_esw_mode(devlink); >>>> +} >>>> + >>>> int mlx5_init_one_devl_locked(struct mlx5_core_dev *dev) >>>> { >>>> bool light_probe = mlx5_dev_is_lightweight(dev); >>>> @@ -1471,6 +1482,8 @@ int mlx5_init_one(struct mlx5_core_dev *dev) >>>> err = mlx5_init_one_devl_locked(dev); >>>> if (err) >>>> devl_unregister(devlink); >>>> + else >>>> + mlx5_devl_apply_default_esw_mode(dev); >>> >>> I don't understand why this patch is needed at all. Just leave the job >>> to the devlink core, no? That was the point to not pollute drivers with >>> code like this. Is it some kind of leftover? >> >> It was discussed with Jakub here: >> https://lore.kernel.org/all/20260611085440.4fe36bf2@kernel.org/ >> >> The main reason is timing. If the default is applied only by devlink >> core, it has to wait until the driver drops the devlink lock. > > I don't follow. > > > devl_lock(devlink); > if (dev->shd) { > err = devl_nested_devlink_set(dev->shd, devlink); > if (err) > goto unlock; > } > devl_register(devlink); > err = mlx5_init_one_devl_locked(dev); > if (err) > devl_unregister(devlink); > unlock: > devl_unlock(devlink); > > > devlink lock is droped right after. Earlier versions had the fw reset / recovery flows covered as well. The regular probe/init in mlx5 need some changes in mlx5 so I can move it earlier, left the API just to make sure we are aligned and it could be used be a later patches. Anyway, I guess I can drop this as well and continue with followup patches just to keep forward progress. > > > >> For mlx5, that usually happens very late in the init sequence. I >> wanted drivers to be able to apply the default as soon as the driver >> is ready for it, because on NICs with a DPU the host PF can remain >> stuck until the ECPF moves to switchdev. >> >> This API is also useful beyond the initial devlink registration path. >> Follow-up patches will use it for driver controlled paths that are >> not covered by the devlink core, such as recovery and FW reset. >> >> There is also a race window where userspace may take the devlink lock >> before the core gets a chance to apply the default. Letting the driver >> explicitly apply the default at the right point avoids that scenario. >> >> Thinking about this again, maybe the simpler approach is to apply the >> default from devl_unlock(). That would avoid the whole workqueue >> infra. >> >> I avoided doing that earlier because applying a default mode as a >> side effect of devl_unlock() feels a bit odd. But compared to adding >> dedicated workqueue handling maybe it is the lesser evil here. >> >> What do you think? > > I was under impression that you need the work to resolve nested locking. > If not, drop it, sure. I think that should be fine. Once the instance is registered and the devlink lock is dropped, the driver should be ready for normal devlink operations anyway, since a user could trigger the same path at that point, so we just don't drop the lock and call the driver directly, should work. The only caveat I can think of is a driver holding some other lock while dropping the devlink lock, and then trying to take that same lock again from the mode-setting callback. But that sounds like a driver bug rather than something devlink should work around. I’ll drop the workqueue approach and rework this for v6 :) Mark > > >> >> About the extra API, I still think it's useful and would like to keep >> it if possible. >> >> Mark >> >> >>> >>> >>> >>>> unlock: >>>> devl_unlock(devlink); >>>> return err; >>>> -- >>>> 2.43.0 >>>> >>