Subject: Re: [PATCH net-next] ptp: Move from simple ida to xarray

From: Simon Horman <[email-masked]>
Date: Fri, 8 Mar 2024 21:07:45 +0000

On Thu, Mar 07, 2024 at 11:03:26AM +0100, Kory Maincent wrote:
> Move from simple ida to xarray for storing and loading the ptp_clock
> pointer. This prepares support for future hardware timestamp selection by
> being able to link the ptp clock index to its pointer.
> 
> Signed-off-by: Kory Maincent <[email-masked]>

...

> @@ -246,11 +246,10 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
>  	if (ptp == NULL)
>  		goto no_memory;
>  
> -	index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
> -	if (index < 0) {
> -		err = index;
> +	err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
> +		       GFP_KERNEL);
> +	if (err)
>  		goto no_slot;
> -	}
>  
>  	ptp->clock.ops = ptp_clock_ops;
>  	ptp->info = info;

Hi Kory,

Prior to this change err was -ENOMEM at this point. Now it is 0.

And The immediately following code is:

	ptp->devid = MKDEV(major, index);
	ptp->index = index;
	INIT_LIST_HEAD(&ptp->tsevqs);
	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
	if (!queue)
		goto no_memory_queue;

The goto above results in:

	return ERR_PTR(err);

But here err is 0. This does not seem correct.

Flagged by Smatch.

...

-- 
pw-bot: changes-requested