Re: [PATCH v3 1/2] driver core: Rework logic in __driver_deferred_probe_check_state to allow EPROBE_DEFER to be returned for longer

From: John Stultz <john.stultz@linaro.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Rob Herring <robh@kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Kevin Hilman <khilman@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>, Pavel Machek <pavel@ucw.cz>,
	Len Brown <len.brown@intel.com>, Todd Kjos <tkjos@google.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] driver core: Rework logic in __driver_deferred_probe_check_state to allow EPROBE_DEFER to be returned for longer
Date: Tue, 18 Feb 2020 16:19:05 -0800	[thread overview]
Message-ID: <CALAqxLWtYfwCzDRVecWF8yRQSKQZh-N2g0SifageUaG0QhBGJg@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VcPL7DYp9hjgMu+d=CE=g+V7ZxT9ZyXX-OjEW_JQ4m_nA@mail.gmail.com>

On Tue, Feb 18, 2020 at 4:06 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Wednesday, February 19, 2020, John Stultz <john.stultz@linaro.org> wrote:
>> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
>> index b25bcab2a26b..9d916a7b56a6 100644
>> --- a/drivers/base/dd.c
>> +++ b/drivers/base/dd.c
>> @@ -237,13 +237,12 @@ __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
>>
>>  static int __driver_deferred_probe_check_state(struct device *dev)
>>  {
>> -       if (!initcalls_done)
>> -               return -EPROBE_DEFER;
>
>
> Why to touch this? Can't you simple add a new condition here 'if (deferred_probe_timeout > 0)'... ?

I think that might work. I'll give it a spin later tonight and double check it.

The main thing I wanted to do is fix the logic hole in the current
code where after initcalls_done=true but before deferred_probe_timeout
has expired we just fall through and return 0, which results in an
ENODEV being returned from the calling function.

thanks
-john