linux-kernel - Re: [PATCH] gpio: gpio-tb10x: remove incorrect _

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Message-ID: <20150325171453.GA40952@dtor-ws>
Date:	Wed, 25 Mar 2015 10:14:53 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Linus Walleij <linus.walleij@...aro.org>
Cc:	Alexandre Courbot <gnurou@...il.com>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: gpio-tb10x: remove incorrect __exit markup

On Wed, Mar 25, 2015 at 04:32:13PM +0100, Linus Walleij wrote:
> On Wed, Mar 18, 2015 at 5:55 PM, Dmitry Torokhov
> <dmitry.torokhov@...il.com> wrote:
> > On Tue, Mar 17, 2015 at 01:30:15PM +0100, Linus Walleij wrote:
> >> On Mon, Mar 9, 2015 at 7:04 PM, Dmitry Torokhov
> >> <dmitry.torokhov@...il.com> wrote:
> >>
> >> > Even if bus is not hot-pluggable, the devices can be unbound from the
> >> > driver via sysfs, so we should not be using __exit annotations on
> >> > remove() methods. The only exception is drivers registered with
> >> > platform_driver_probe() which specifically disables sysfs bind/unbind
> >> > attributes.
> >> >
> >> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> >>
> >> I prefer to have this fixed by setting
> >> .suppress_bind_attrs = true
> >> in the struct device_driver .drv portion of the device driver,
> >> so the driver cannot be removed from sysfs.
> >>
> >> So platform_driver_probe() isn't really the only exception,
> >> there is a way to do the same supression on ordinary drivers
> >> if we know we won't fiddle with them from sysfs.
> >
> > Yes, you are right, setting suppress_bind_attrs will work too.
> >
> >>
> >> Can you make a patch as per above (alternatively tell me
> >> how wrong I am...)
> >
> > Unfortunately I won't be able to do that as I can't provide
> > justification for such change (i.e. I do not know why you want to
> > disable unbinding while still keeping the remove() implementation.
> 
> You are right, I want a patch deleting the remove() implementation
> and setting the .suppress_bind_attrs = true at the same time.
> 
> For a bool driver of this type (typically compiled in and probed
> at boot) that makes most sense to me.

Hmm, I do not think this is a good justification for disabling
unbinding. However, as far as I can see, removing gpiochip will succeed
even though there are users of gpios in the system and that might
justify the change. But does this mean that we give up on making
gpiochip clean up properly and we should schedule gpiochip_remove() and
the rest of gpio cleanup infrastructure for removal and declare that
gpio drivers can not ever be made modules?

Seems like wrong direction to move to...

Thanks.

-- 
Dmitry
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