Re: [RFC PATCH v2 3/3] libmultipath: change log level for null uid_attribute

[Martin Wilck <martin.wilck@suse.com>]

On Wed, 2020-09-23 at 23:59 -0500, Benjamin Marzinski wrote:
> If uid_attribute is explicitly set to an empty string, multipath
> should
> log the uid at the default log level, since using the fallback code
> is
> the expected behavior.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> ---
>  libmultipath/discovery.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
> index f650534f..435f2639 100644
> --- a/libmultipath/discovery.c
> +++ b/libmultipath/discovery.c
> @@ -2091,7 +2091,8 @@ get_uid (struct path * pp, int path_state,
> struct udev_device *udev,
>  		}
>  		if ((!udev_available || (len <= 0 && allow_fallback))
>  		    && has_uid_fallback(pp)) {
> -			used_fallback = 1;
> +			if (udev_available || !(udev && pp-
> >uid_attribute))
> +				used_fallback = 1;
>  			len = uid_fallback(pp, path_state, &origin);
>  		}
>  	}

Uff, this logic was convoluted anyway, now it's even harder to grasp.
IIUC, if !udev, used_fallback will be set to 1, even if 
pp->uid_attribute is the empty string. Is that intended?
To make this easier to read, I'd suggest something like this:

		bool valid_uid_attr = pp->uid_attribute
			&& *pp->uid_attribute;
		bool empty_uid_attr = pp->uid_attribute
			&& !*pp->uid_attribute;
		bool udev_available = udev && valid_uid_attr;
      ...
		if ((!udev_available || (len <= 0 && allow_fallback))
		    && has_uid_fallback(pp)) {
			if (!empty_uid_attr)
				used_fallback = 1;
			len = uid_fallback(pp, path_state, &origin);

Regards,
Martin

-- 
Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
SUSE  Software Solutions Germany GmbH
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