Re: [PATCH RFC] driver core: bus: Correct return value for storing bus attribute drivers_probe

[Zijun Hu <zijun_hu@icloud.com>]

On 2024/8/26 20:23, Zijun Hu wrote:
> From: Zijun Hu <quic_zijuhu@quicinc.com>
> 
> drivers_probe_store() regards bus_rescan_devices_helper()'s returned
> value 0 as success when find driver for a single device user specify
> that is wrong since the following 3 failed cases also return 0:
> 
> (1) the device is dead
> (2) bus fails to match() the device with any its driver
> (3) bus fails to probe() the device with any its driver
> 
> Fixed by only regarding successfully attaching the device to a driver
> as success.
> 
> Fixes: b8c5cec23d5c ("Driver core: udev triggered device-<>driver binding")
> Cc: stable@vger.kernel.org
> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> ---
>  drivers/base/bus.c | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/bus.c b/drivers/base/bus.c
> index abf090ace833..0a994e63785c 100644
> --- a/drivers/base/bus.c
> +++ b/drivers/base/bus.c
> @@ -40,6 +40,20 @@ static struct kset *bus_kset;
>  	struct driver_attribute driver_attr_##_name =		\
>  		__ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
>  
> +/* Bus rescans drivers for a single device */
> +static int __must_check bus_rescan_single_device(struct device *dev)
> +{
> +	int ret;
> +
> +	if (dev->parent && dev->bus->need_parent_lock)
> +		device_lock(dev->parent);
> +	ret = device_attach(dev);
> +	if (dev->parent && dev->bus->need_parent_lock)
> +		device_unlock(dev->parent);
> +
> +	return ret;
> +}
> +
>  static int __must_check bus_rescan_devices_helper(struct device *dev,
>  						void *data);
>  
> @@ -311,12 +325,19 @@ static ssize_t drivers_probe_store(const struct bus_type *bus,
>  {
>  	struct device *dev;
>  	int err = -EINVAL;
> +	int res;
>  
>  	dev = bus_find_device_by_name(bus, NULL, buf);
>  	if (!dev)
>  		return -ENODEV;
> -	if (bus_rescan_devices_helper(dev, NULL) == 0)
> +
> +	res = bus_rescan_single_device(dev);
> +	/* Propagate error code upwards as far as possible */
> +	if (res < 0)
> +		err = res;
> +	else if (res == 1)
>  		err = count;
> +
>  	put_device(dev);
>  	return err;
>  }
> 

please ignore RFC for this patch, will push it within a patch
series.

thanks
> ---
> base-commit: 888f67e621dda5c2804a696524e28d0ca4cf0a80
> change-id: 20240826-fix_drivers_probe-88c6a2cc1899
> 
> Best regards,