Re: [PATCH net-next V4 4/6] devlink: Apply eswitch mode boot defaults

[Paolo Abeni <pabeni@redhat.com>]

On 6/29/26 8:20 PM, Mark Bloch wrote:
> Apply parsed devlink_eswitch_mode= defaults after devlink registration
> and after successful reload.
> 
> devl_register() may still be called before the device is ready for an
> eswitch mode change, so keep a per-devlink delayed work item and pending
> flag for the registration path. Registration queues the work, and the
> worker tries to take the devlink instance lock.
> 
> If the lock is busy, the worker requeues itself with a delay.
> 
> For successful reloads that performed DRIVER_REINIT, devlink_reload()
> already holds the devlink instance lock and the driver has completed
> reload_up(). Clear pending work and apply the default directly from the
> reload path instead of queueing work.
> 
> If a user sets eswitch mode through netlink before the pending
> registration work runs, clear the pending flag so the queued default does
> not override that user request. Cancel pending default apply work when
> freeing the devlink instance.
> 
> Signed-off-by: Mark Bloch <mbloch@nvidia.com>
> ---
>  net/devlink/core.c          | 198 +++++++++++++++++++++++++++++++-----
>  net/devlink/dev.c           |   6 ++
>  net/devlink/devl_internal.h |   5 +
>  3 files changed, 182 insertions(+), 27 deletions(-)
> 
> diff --git a/net/devlink/core.c b/net/devlink/core.c
> index 5126509a9c4e..998e4ffd5dce 100644
> --- a/net/devlink/core.c
> +++ b/net/devlink/core.c
> @@ -5,6 +5,7 @@
>   */
>  
>  #include <linux/init.h>
> +#include <linux/jiffies.h>
>  #include <linux/list.h>
>  #include <linux/slab.h>
>  #include <linux/string.h>
> @@ -22,8 +23,12 @@ DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
>  
>  static char *devlink_default_esw_mode_param;
>  static bool devlink_default_esw_mode_match_all;
> +static bool devlink_default_esw_mode_enabled;
>  static enum devlink_eswitch_mode devlink_default_esw_mode;
>  static LIST_HEAD(devlink_default_esw_mode_nodes);
> +static struct workqueue_struct *devlink_default_esw_mode_wq;
> +
> +#define DEVLINK_DEFAULT_ESW_MODE_APPLY_DELAY msecs_to_jiffies(100)
>  
>  struct devlink_default_esw_mode_node {
>  	struct list_head list;
> @@ -166,6 +171,7 @@ static void __init devlink_default_esw_mode_nodes_clear(void)
>  	}
>  
>  	devlink_default_esw_mode_match_all = false;
> +	devlink_default_esw_mode_enabled = false;
>  }
>  
>  static int __init devlink_default_esw_mode_parse(char *str)
> @@ -192,14 +198,113 @@ static int __init devlink_default_esw_mode_parse(char *str)
>  		return err;
>  
>  	err = devlink_default_esw_mode_handles_parse(handles);
> -	if (err)
> +	if (err) {
>  		devlink_default_esw_mode_nodes_clear();
> -	else
> +	} else {
>  		devlink_default_esw_mode = esw_mode;
> +		devlink_default_esw_mode_enabled = true;
> +	}
>  
>  	return err;
>  }
>  
> +static bool devlink_default_esw_mode_match(struct devlink *devlink)
> +{
> +	const char *bus_name = devlink_bus_name(devlink);
> +	const char *dev_name = devlink_dev_name(devlink);
> +	struct devlink_default_esw_mode_node *node;
> +
> +	if (devlink_default_esw_mode_match_all)
> +		return true;
> +
> +	node = devlink_default_esw_mode_node_find(bus_name, dev_name);
> +	return !!node;
> +}
> +
> +void devlink_default_esw_mode_apply(struct devlink *devlink)
> +{
> +	const struct devlink_ops *ops = devlink->ops;
> +	int err;
> +
> +	devl_assert_locked(devlink);
> +
> +	if (!devlink_default_esw_mode_match(devlink))
> +		return;
> +
> +	if (!ops->eswitch_mode_set) {
> +		if (!devlink_default_esw_mode_match_all)
> +			devl_warn(devlink,
> +				  "devlink_eswitch_mode= selected this device but eswitch mode setting is not supported\n");

Not a very strong opinion on my side, but I *think* it would be more
consistent to emit this warning even for devlink_default_esw_mode_match_all

/P