Re: [PATCH 1/3] driver core: check notifier_call_chain return value

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Feb 27, 2018 at 03:09:24PM +0100, Benjamin Gaignard wrote:
> When being notified that a driver is about to be bind a listener
> could return NOTIFY_BAD.
> Check the return to be sure that the driver could be bind.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
> ---
>  drivers/base/dd.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index de6fd092bf2f..9275f2c0fed2 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -304,9 +304,12 @@ static int driver_sysfs_add(struct device *dev)
>  {
>  	int ret;
>  
> -	if (dev->bus)
> -		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> -					     BUS_NOTIFY_BIND_DRIVER, dev);
> +	if (dev->bus) {
> +		if (blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> +						 BUS_NOTIFY_BIND_DRIVER, dev) ==
> +						 NOTIFY_BAD)
> +			return -EINVAL;

checkpatch does not complain about this?

And what is going to break when we enable this, as we have never checked
this before?

thanks,

greg k-h