linux-kernel - Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall

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Date:   Mon, 12 Aug 2019 17:01:09 +0200
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Max Staudt <max@...as.org>
Cc:     axboe@...nel.dk, linux-ide@...r.kernel.org,
        linux-m68k@...r.kernel.org, linux-kernel@...r.kernel.org,
        glaubitz@...sik.fu-berlin.de, schmitzmic@...il.com,
        geert@...ux-m68k.org
Subject: Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of
 initcall


On 8/12/19 4:26 PM, Max Staudt wrote:
> On 08/12/2019 02:15 PM, Bartlomiej Zolnierkiewicz wrote:
>>> What's a good way to do that, given that we now have module_exit()> defined and an exit function is void?
>>
>> What about something like this:
>>
>> static bool xsurf_present;
>> ...
>> static int __init pata_buddha_late_init(void)
>> ...
>> 		if (pata_buddha_probe(z, &xsurf_ent) == 0 &&
>> 		    xsurf_present == false)
>> 			xsurf_present = true;
>> ...
>> static void __exit pata_buddha_exit(void)
>> ...
>> 	if (xsurf_present)
>> 		return -EBUSY;
>> ...
>>
>> ?
> 
> Okay, so we're talking about the same idea. Great!
> 
> Unfortunately, pata_buddha_exit() is void, and thus can't fail. According to Documentation/kernel-hacking/hacking.rst this is by design.

You are of course right and the example code is broken
(+ I need more caffeine).

> Any other ideas? We could also continue to disallow unloading completely until MFD support comes along.
Yes, this would also be OK.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics