Re: [PATCH v7 2/4] driver core: add deferring probe reason to devices_deferred property

From: Andy Shevchenko
Date: Mon Jun 29 2020 - 15:02:53 EST


On Mon, Jun 29, 2020 at 2:22 PM Andrzej Hajda <a.hajda@xxxxxxxxxxx> wrote:
>
> /sys/kernel/debug/devices_deferred property contains list of deferred devices.
> This list does not contain reason why the driver deferred probe, the patch
> improves it.
> The natural place to set the reason is dev_err_probe function introduced recently,
> ie. if dev_err_probe will be called with -EPROBE_DEFER instead of printk the message
> will be attached to deferred device and printed when user read devices_deferred

to a deferred

reads

> property.

...

> @@ -3984,10 +3986,12 @@ int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
> vaf.fmt = fmt;
> vaf.va = &args;
>
> - if (err != -EPROBE_DEFER)

> + if (err != -EPROBE_DEFER) {

Why not positive conditional? (Okay, I'm fine with either in this case)

> dev_err(dev, "error %d: %pV", err, &vaf);
> - else
> + } else {
> + device_set_deferred_probe_reson(dev, &vaf);
> dev_dbg(dev, "error %d: %pV", err, &vaf);
> + }

To reduce churn, you may move {} addition to the first patch.

...

> list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
> - seq_printf(s, "%s\n", dev_name(curr->device));
> + seq_printf(s, "%s\t%s", dev_name(curr->device),
> + curr->device->p->deferred_probe_reason ?: "\n");

Hmm... "\t" will be dangling in the latter case.

--
With Best Regards,
Andy Shevchenko