[PATCH] ACPI: AGDI: Improve error reporting for problems during .remove()

[Uwe Kleine-König]

Hello James,

On Wed, Oct 26, 2022 at 05:09:40PM +0100, James Morse wrote:
> Hi guys,
> 
> On 18/10/2022 10:35, Lorenzo Pieralisi wrote:
> > On Fri, Oct 14, 2022 at 06:06:23PM +0200, Uwe Kleine-K�nig wrote:
> >> Returning an error value in a platform driver's remove callback results in
> >> a generic error message being emitted by the driver core, but otherwise it
> >> doesn't make a difference. The device goes away anyhow.
> >>
> >> So instead of triggering the generic platform error message, emit a more
> >> helpful message if a problem occurs and return 0 to suppress the generic
> >> message.
> >>
> >> This patch is a preparation for making platform remove callbacks return
> >> void.
> > 
> > If that's the plan - I don't have anything against this patch.
> > 
> >> Signed-off-by: Uwe Kleine-K�nig <u.kleine-koenig at pengutronix.de>
> >> ---
> >> Hello,
> >>
> >> note that in the situations where the driver returned an error before
> >> and now emits a message, there is a resource leak. Someone who knows
> >> more about this driver and maybe even can test stuff, might want to
> >> address this. This might not only be about non-freed memory, the device
> >> disappears but it is kept in sdei_list and so might be used after being
> >> gone.
> 
> > I'd need James' input on this. I guess we may ignore
> > sdei_event_disable() return value and continue anyway in agdi_remove(),
> > whether that's the right thing to do it is a different question.
> 
> The unregister stuff is allowed to fail if the event is 'in progress' on another CPU.
> Given the handler panic()s the machine, if an event is in progress, the resource leak
> isn't something worth worrying about. The real problem is that the handler code may be
> free()d while another CPU is still executing it, which is only a problem for modules.
> 
> As this thing can't be built as a module, and the handler panic()s the machine, I don't
> think there is going to be a problem here.

Is that an Ack?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
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