From: "Michał Nazarewicz" <m.nazarewicz@samsung•com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix•de>
Cc: "Cliff Cai" <cliff.cai@analog•com>,
"Greg Kroah-Hartman" <gregkh@suse•de>,
"Dinh Nguyen" <Dinh.Nguyen@freescale•com>,
"Tony Lindgren" <tony@atomide•com>,
"Nicolas Ferre" <nicolas.ferre@atmel•com>,
linux-kernel@vger•kernel.org, linuxppc-dev@ozlabs•org,
"Julia Lawall" <julia@diku•dk>,
"Philipp Zabel" <philipp.zabel@gmail•com>,
"Mark Brown" <broonie@opensource•wolfsonmicro.com>,
"Felipe Balbi" <felipe.balbi@nokia•com>,
"Andrea Gelmini" <andrea.gelmini@gelma•net>,
"Robert Jarzmik" <robert.jarzmik@free•fr>,
"Fabien Chouteau" <fabien.chouteau@barco•com>,
"Dan Carpenter" <error27@gmail•com>,
"David Brownell" <dbrownell@users•sourceforge.net>,
"Vladimir Zapolskiy" <vzapolskiy@gmail•com>,
"Sergei Shtylyov" <sshtylyov@ru•mvista.com>,
"Vincent Sanders" <support@simtec•co.uk>,
"Marc Singer" <elf@buici•com>,
"André Goddard Rosa" <andre.goddard@gmail•com>,
"Alan Stern" <stern@rowland•harvard.edu>,
"Sean MacLennan" <smaclennan@pikatech•com>,
"Russell King" <rmk+kernel@arm•linux.org.uk>,
"Tobias Klauser" <tklauser@distanz•ch>,
"Marc Kleine-Budde" <m.kleine-budde@pengutronix•de>,
"Eirik Aanonsen" <eaa@wprmedical•com>,
"Mike Frysinger" <vapier@gentoo•org>,
"Thomas Dahlmann" <dahlmann.thomas@arcor•de>,
linux-geode@lists•infradead.org,
"Ben Dooks" <ben-linux@fluff•org>,
"Magnus Damm" <damm@igel•co.jp>,
"Anton Vorontsov" <avorontsov@ru•mvista.com>,
"Andrew Victor" <linux@maxim•org.za>,
linux-arm-kernel@lists•infradead.org,
"Anatolij Gustschin" <agust@denx•de>,
"Eric Miao" <eric.y.miao@gmail•com>,
"Németh Márton" <nm127@freemail•hu>,
"Jiri Kosina" <jkosina@suse•cz>,
"Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas•com>,
linux-usb@vger•kernel.org, "Harro Haan" <hrhaan@gmail•com>,
"FUJITA Tomonori" <fujita.tomonori@lab•ntt.co.jp>,
"H Hartley Sweeten" <hsweeten@visionengravers•com>,
"Paul Mundt" <lethal@linux-sh•org>, "Tejun Heo" <tj@kernel•org>,
"Andrew Morton" <akpm@linux-foundation•org>,
"Cory Maccarrone" <darkstar6262@gmail•com>
Subject: Re: [PATCH RFC] usb gadget: introduce usb_gadget_probe_driver
Date: Fri, 30 Jul 2010 18:08:23 +0200 [thread overview]
Message-ID: <op.vgny39097p4s8u@pikus> (raw)
In-Reply-To: <20100730152602.GA28042@pengutronix.de>
On Fri, 30 Jul 2010 17:26:02 +0200, Uwe Kleine-K=C3=B6nig <u.kleine-koen=
ig@pengutronix•de> wrote:
> On Fri, Jul 30, 2010 at 05:16:46PM +0200, Micha=C5=82 Nazarewicz wrote=
:
>> On Fri, 30 Jul 2010 16:49:14 +0200, Uwe Kleine-K=C3=B6nig <u.kleine-k=
oenig@pengutronix•de> wrote:
>>
>>> This is like usb_gadget_register_driver with the only difference tha=
t it
>>> gets the bind function as parameter instead of using driver->bind. =
This
>>> allows fixing section mismatches like
>>>
>>> WARNING: drivers/usb/gadget/g_printer.o(.data+0xc): Section mismatc=
h in
>>> reference from the variable printer_driver to the function
>>> .init.text:printer_bind()
>>> The variable printer_driver references
>>> the function __init printer_bind()
>>>
>>> by using usb_gadget_probe_driver with driver->bind =3D NULL. When a=
ll
>>> drivers are fixed to use the new function the bind member of struct
>>> usb_gadget_driver can go away.
>>>
>>> Signed-off-by: Uwe Kleine-K=C3=B6nig <u.kleine-koenig@pengutronix•de=
>
>>> Cc: Michal Nazarewicz <m.nazarewicz@samsung•com>
>>> Cc: Greg Kroah-Hartman <gregkh@suse•de>
BTW. Dunno if there is a reason to put me on Cc and Greg will be in
Signed-off-by anyway.
>>> ---
>>> Hello,
>>>
>>> there is an alternative patch in Greg's tree [1], but IMHO mine is
>>> better as it doesn't need __ref.
>>>
>>> Thoughts?
>>
>> Personally I don't see advantage of this over changing the __init to =
__ref.
>> Or am I missing something? I see your patch as an unnecessary API ch=
ange.
>> The way I understand it, __ref was introduced exactly for cases like =
this
>> one where function is referenced from "normal" data but used only dur=
ing
>> init. Could you try to clarify for me why you think your solution is=
>> better then mine?
> - Using __ref instead of __init moves all bind functions from .init.te=
xt
> to .text and so the code isn't freed after booting or module loading=
.
> (OK, you could fix this by marking the driver structs as __ref and
> keep __init for the bind functions.)
I believe this to be untrue. __ref puts code in .ref.text which AFAIK i=
s
freed.
> - Using __ref might hide section mismatches. (Your patch hasn't this
> problem as the bind functions used to live in .init.text, so any
> reference to .init should be OK assuming that it was OK to live in
> .init.text in the first place. But when marking the driver structs
> this is an issue.) That's why I don't like __ref and said my patch
> were better as it doesn't make use of it.
>
> - The bind functions are only called at init time, so there is no need=
> to save a pointer to it.
OK, I see some merit in this approach. However, the same issue is with
usb_configuration and ?usb_composite_driver -- those should be changed
in the same way or it would defeat the purpose of the patch.
-- =
Best regards, _ _
| Humble Liege of Serenely Enlightened Majesty of o' \,=3D./ `o
| Computer Science, Micha=C5=82 "mina86" Nazarewicz (o o)
+----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--
next prev parent reply other threads:[~2010-07-30 16:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-30 14:49 [PATCH RFC] usb gadget: introduce usb_gadget_probe_driver Uwe Kleine-König
2010-07-30 15:14 ` Julia Lawall
2010-07-30 15:28 ` Uwe Kleine-König
2010-07-30 15:16 ` Michał Nazarewicz
2010-07-30 15:26 ` Uwe Kleine-König
2010-07-30 16:08 ` Michał Nazarewicz [this message]
2010-07-30 18:57 ` Uwe Kleine-König
2010-07-30 18:46 ` David Brownell
2010-08-02 9:39 ` Michał Nazarewicz
2010-08-02 12:39 ` [PATCH] usb gadget: don't save bind callback in struct usb_gadget_driver Uwe Kleine-König
2010-08-02 12:51 ` Julia Lawall
2010-08-02 13:12 ` Uwe Kleine-König
2010-08-02 22:54 ` Greg KH
2010-08-02 14:25 ` Michał Nazarewicz
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