On Mon, Jun 07, 2021 at 09:55:45PM -0300, Jason Gunthorpe 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.
Why does that matter? Why does it need to know this?
> Reorganize things so that really_probe() always returns an error code on
> failure and 0 on success. Move the special code for device list walking
> into the walker callback __device_attach_driver() and trigger it based on
> an output flag from really_probe(). Update the rest of the API surface to
> return a normal -ERR or 0 on success.
>
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> ---
> drivers/base/bus.c | 6 +----
> drivers/base/dd.c | 61 ++++++++++++++++++++++++++++++----------------
> 2 files changed, 41 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/base/bus.c b/drivers/base/bus.c
> index 36d0c654ea6124..03591f82251302 100644
> --- a/drivers/base/bus.c
> +++ b/drivers/base/bus.c
> @@ -212,13 +212,9 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf,
> dev = bus_find_device_by_name(bus, NULL, buf);
> if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
> err = device_driver_attach(drv, dev);
> -
> - if (err > 0) {
> + if (!err) {
> /* success */
> err = count;
> - } else if (err == 0) {
> - /* driver didn't accept device */
> - err = -ENODEV;
> }
> }
> put_device(dev);
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index c1a92cff159873..7fb58e6219b255 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -513,7 +513,13 @@ static ssize_t state_synced_show(struct device *dev,
> }
> static DEVICE_ATTR_RO(state_synced);
>
> -static int really_probe(struct device *dev, struct device_driver *drv)
> +enum {
> + /* Set on output if the -ERR has come from a probe() function */
> + PROBEF_DRV_FAILED = 1 << 0,
> +};
> +
> +static int really_probe(struct device *dev, struct device_driver *drv,
> + unsigned int *flags)
Ugh, no, please no functions with random "flags" in them, that way lies
madness and unmaintainable code for decades to come.
Especially as I have no idea what this is trying to solve here at all...
greg k-h
