linux-kernel - Re: [PATCH 2/3] driver core: Introduce fw_devlink_relax

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Message-ID: <2025081429-lair-esophagus-eb8b@gregkh>
Date: Thu, 14 Aug 2025 13:39:02 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Wang Wensheng <wangwensheng4@...wei.com>
Cc: rafael@...nel.org, dakr@...nel.org, tglx@...utronix.de,
	saravanak@...gle.com, robh@...nel.org, broonie@...nel.org,
	linux-kernel@...r.kernel.org, chenjun102@...wei.com
Subject: Re: [PATCH 2/3] driver core: Introduce fw_devlink_relax_consumers
 helper

On Thu, Aug 14, 2025 at 07:10:22PM +0800, Wang Wensheng wrote:
> Some devices are added during its parent's probe and will never get
> bound to a driver. In this case, with fw_devlink set to "rpm",
> which is the default value, its consumers will be deferred probe
> until deferred_probe_timeout when fw_devlink_drivers_done() would
> relax the devlinks to the suplier.
> 
> Use this function to relax the consumer devlinks, just like what we
> do for the unmatched devices in fw_devlink_drivers_done(), so that
> the consumer devices would be probed not that later.
> 
> Signed-off-by: Wang Wensheng <wangwensheng4@...wei.com>
> ---
>  drivers/base/core.c    | 22 ++++++++++++++++++++++
>  include/linux/device.h |  1 +
>  2 files changed, 23 insertions(+)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index d22d6b23e758..2f7101ad9d11 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1754,6 +1754,28 @@ static void fw_devlink_relax_link(struct device_link *link)
>  		dev_name(link->supplier));
>  }
>  
> +/**
> + * fw_devlink_relax_consumers - Relax the devlinks with all its consumers
> + * @dev: Device whose consumer devlinks will be relaxed
> + *
> + * Some devices are added during its parent's probe and will never get bound
> + * to a driver. In this case its consumers will be deferred probe until
> + * deferred_probe_timeout.
> + *
> + * Use this function to relax the consumer devlinks so that the consumers
> + * device would be probed not that later.
> + */
> +void fw_devlink_relax_consumers(struct device *dev)
> +{
> +	struct device_link *link;
> +
> +	device_links_write_lock();
> +	list_for_each_entry(link, &dev->links.consumers, s_node)
> +		fw_devlink_relax_link(link);
> +	device_links_write_unlock();
> +}
> +EXPORT_SYMBOL_GPL(fw_devlink_relax_consumers);

We currently do not export any "fw_" functions from the driver core, why
do that now?  This feels wrong as this should all be "internal" to the
driver core, no driver should be calling this.

thanks,

greg k-h