Re: [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jun 14, 2021 at 05:08:39PM +0200, Christoph Hellwig wrote:
> Currently really_probe() returns 1 on success and 0 if the probe() call
> fails. This return code arrangement is designed to be useful for
> __device_attach_driver() which is walking the device list and trying every
> driver. 0 means to keep trying.
> 
> However, it is not useful for the other places that call through to
> really_probe() that do actually want to see the probe() return code.
> 
> For instance bind_store() would be better to return the actual error code
> from the driver's probe method, not discarding it and returning -ENODEV.
> 
> Reorganize things so that really_probe() returns the error code from
> ->probe as a (inverted) positive number, and 0 for successful attach.
> 
> With this, __device_attach_driver can ignore the (positive) probe errors,
> return 1 to exit the loop for a successful binding and pass on the
> other negative errors, while device_driver_attach simplify inverts the
> positive errors and returns all errors to the sysfs code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/base/bus.c |  6 +-----
>  drivers/base/dd.c  | 29 ++++++++++++++++++++---------
>  2 files changed, 21 insertions(+), 14 deletions(-)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>