Re: [PATCH v3 06/12] of: overlay: detect cases where device tree may become corrupt

From: Alan Tull
Date: Thu Oct 19 2017 - 15:04:48 EST


On Tue, Oct 17, 2017 at 6:36 PM, <frowand.list@xxxxxxxxx> wrote:

> static int overlay_notify(struct overlay_changeset *ovcs,
> enum of_overlay_notify_action action)
> {
> @@ -86,8 +109,14 @@ static int overlay_notify(struct overlay_changeset *ovcs,
>
> ret = blocking_notifier_call_chain(&overlay_notify_chain,
> action, &nd);
> - if (ret)
> - return notifier_to_errno(ret);
> + if (ret == NOTIFY_STOP)
> + return 0;
> + if (ret) {
> + ret = notifier_to_errno(ret);
> + pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
> + of_overlay_action_name[action], ret, nd.target);
> + return ret;
> +

Hi Frank,

This will spew lots of "error 0" messages for every notifier that
returns NOTIFY_OK.

rmdir /sys/kernel/config/device-tree/overlays/1
[ 131.972505] OF: overlay: overlay changeset pre-remove notifier
error 0, target: /soc/base_fpga_region/fpga_pr_region0
[ 131.987879] OF: overlay: overlay changeset post-remove notifier
error 0, target: /soc/base_fpga_region/fpga_pr_region0

I could change fpga-region.c to return NOTIFY_STOP if it is accepting
the overlay, but it will still want to return NOTIFY_OK for every case
where it doesn't have an opinion.

Alan

> }
>
> return 0;