[LTP] [PATCH net v1] ptp: Make max_phase_adjustment sysfs device attribute invisible when not supported

[Andrew Lunn]

On Tue, Jun 27, 2023 at 04:21:39PM -0700, Rahul Rameshbabu wrote:
> The .adjphase operation is an operation that is implemented only by certain
> PHCs. The sysfs device attribute node for querying the maximum phase
> adjustment supported should not be exposed on devices that do not support
> .adjphase.
> 
> Fixes: c3b60ab7a4df ("ptp: Add .getmaxphase callback to ptp_clock_info")
> Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Link: https://lore.kernel.org/netdev/20230627162146.GA114473@dev-arch.thelio-3990X/
> Link: https://lore.kernel.org/all/CA+G9fYtKCZeAUTtwe69iK8Xcz1mOKQzwcy49wd+imZrfj6ifXA@mail.gmail.com/

I think Signed-off-by should be last.

> diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
> index 77219cdcd683..6e4d5456a885 100644
> --- a/drivers/ptp/ptp_sysfs.c
> +++ b/drivers/ptp/ptp_sysfs.c
> @@ -358,6 +358,9 @@ static umode_t ptp_is_attribute_visible(struct kobject *kobj,
>  		   attr == &dev_attr_max_vclocks.attr) {
>  		if (ptp->is_virtual_clock)
>  			mode = 0;
> +	} else if (attr == &dev_attr_max_phase_adjustment.attr) {
> +		if (!info->adjphase || !info->getmaxphase)
> +			mode = 0;

Maybe it is time to turn this into a switch statement?

I also wounder if this really is something for net. How do you think
this patch matches against the stable rules?

    Andrew