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From: frowand.list@gmail.com (Frank Rowand)
To: linux-arm-kernel@lists.infradead.org
Subject: [Question] refcount of DT node
Date: Thu, 14 Apr 2016 09:10:44 -0700	[thread overview]
Message-ID: <570FC104.80808@gmail.com> (raw)
In-Reply-To: <06E9E2D3-4627-4970-ABBB-34B5ED620709@konsulko.com>

On 4/14/2016 3:02 AM, Pantelis Antoniou wrote:
> Hi Mark,
> 
>> On Apr 14, 2016, at 12:59 , Mark Rutland <mark.rutland@arm.com> wrote:
>>
>> On Thu, Apr 14, 2016 at 09:48:49AM +0100, Russell King - ARM Linux wrote:
>>> On Thu, Apr 14, 2016 at 04:47:57PM +0900, Masahiro Yamada wrote:
>>>> Hi experts.
>>>>
>>>> My understanding of refcount of DT node is poor.
>>>
>>> The message from DT people is... don't worry about DT node refcounting.
>>> Do whatever you want with it, they don't care whether you have correct
>>> refcounting or not.
>>>
>>> The background behind that is that I've tried to fix the refcounting,
>>> and even had the coccinelle people generate some stuff to work on this
>>> issue, but DT people's attitude towards it is "don't bother".
>>>
>>> So yes, people may get it wrong, but it seems it's something that DT
>>> people want ignored.
>>
>> I'm not sure that's quite fair; the last discussion I recall about this
>> ended up concluding that we need a better API, rather than papering over
>> problems.
>>
>> That said, there isn't much obvious progress on that front.
>>
>> Frank, Pantelis, Rob, were there any conclusions on this from ELC, or is
>> this something that needs someone to propose something?
>>
> 
> Frank mentioned that he wants a new API. I have some ideas about it too.
> 
> My take is that drivers should never do reference counting, we have to figure
> out a way for DT access using copy semantics or locks.
> 
> References would still be required for core DT code, but that?s a sane subset.

Yes.  Nothing concrete about implementation was decided at ELC, but this issue
is on my todo list.

-Frank

> 
>> Mark.
>>
>> [1] http://permalink.gmane.org/gmane.linux.drivers.devicetree/153777
> 
> Regards
> 
> ? Pantelis
> 
> .
> 

WARNING: multiple messages have this Message-ID (diff)
From: Frank Rowand <frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Pantelis Antoniou
	<pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Russell King - ARM Linux
	<linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Masahiro Yamada
	<yamada.masahiro-uWyLwvC0a2jby3iVrkZq2A@public.gmane.org>,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>,
	Linux Kernel Mailing List
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-arm-kernel
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [Question] refcount of DT node
Date: Thu, 14 Apr 2016 09:10:44 -0700	[thread overview]
Message-ID: <570FC104.80808@gmail.com> (raw)
In-Reply-To: <06E9E2D3-4627-4970-ABBB-34B5ED620709-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>

On 4/14/2016 3:02 AM, Pantelis Antoniou wrote:
> Hi Mark,
> 
>> On Apr 14, 2016, at 12:59 , Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org> wrote:
>>
>> On Thu, Apr 14, 2016 at 09:48:49AM +0100, Russell King - ARM Linux wrote:
>>> On Thu, Apr 14, 2016 at 04:47:57PM +0900, Masahiro Yamada wrote:
>>>> Hi experts.
>>>>
>>>> My understanding of refcount of DT node is poor.
>>>
>>> The message from DT people is... don't worry about DT node refcounting.
>>> Do whatever you want with it, they don't care whether you have correct
>>> refcounting or not.
>>>
>>> The background behind that is that I've tried to fix the refcounting,
>>> and even had the coccinelle people generate some stuff to work on this
>>> issue, but DT people's attitude towards it is "don't bother".
>>>
>>> So yes, people may get it wrong, but it seems it's something that DT
>>> people want ignored.
>>
>> I'm not sure that's quite fair; the last discussion I recall about this
>> ended up concluding that we need a better API, rather than papering over
>> problems.
>>
>> That said, there isn't much obvious progress on that front.
>>
>> Frank, Pantelis, Rob, were there any conclusions on this from ELC, or is
>> this something that needs someone to propose something?
>>
> 
> Frank mentioned that he wants a new API. I have some ideas about it too.
> 
> My take is that drivers should never do reference counting, we have to figure
> out a way for DT access using copy semantics or locks.
> 
> References would still be required for core DT code, but that’s a sane subset.

Yes.  Nothing concrete about implementation was decided at ELC, but this issue
is on my todo list.

-Frank

> 
>> Mark.
>>
>> [1] http://permalink.gmane.org/gmane.linux.drivers.devicetree/153777
> 
> Regards
> 
> — Pantelis
> 
> .
> 

--
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WARNING: multiple messages have this Message-ID (diff)
From: Frank Rowand <frowand.list@gmail.com>
To: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Russell King - ARM Linux <linux@arm.linux.org.uk>,
	Rob Herring <robh+dt@kernel.org>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	devicetree@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [Question] refcount of DT node
Date: Thu, 14 Apr 2016 09:10:44 -0700	[thread overview]
Message-ID: <570FC104.80808@gmail.com> (raw)
In-Reply-To: <06E9E2D3-4627-4970-ABBB-34B5ED620709@konsulko.com>

On 4/14/2016 3:02 AM, Pantelis Antoniou wrote:
> Hi Mark,
> 
>> On Apr 14, 2016, at 12:59 , Mark Rutland <mark.rutland@arm.com> wrote:
>>
>> On Thu, Apr 14, 2016 at 09:48:49AM +0100, Russell King - ARM Linux wrote:
>>> On Thu, Apr 14, 2016 at 04:47:57PM +0900, Masahiro Yamada wrote:
>>>> Hi experts.
>>>>
>>>> My understanding of refcount of DT node is poor.
>>>
>>> The message from DT people is... don't worry about DT node refcounting.
>>> Do whatever you want with it, they don't care whether you have correct
>>> refcounting or not.
>>>
>>> The background behind that is that I've tried to fix the refcounting,
>>> and even had the coccinelle people generate some stuff to work on this
>>> issue, but DT people's attitude towards it is "don't bother".
>>>
>>> So yes, people may get it wrong, but it seems it's something that DT
>>> people want ignored.
>>
>> I'm not sure that's quite fair; the last discussion I recall about this
>> ended up concluding that we need a better API, rather than papering over
>> problems.
>>
>> That said, there isn't much obvious progress on that front.
>>
>> Frank, Pantelis, Rob, were there any conclusions on this from ELC, or is
>> this something that needs someone to propose something?
>>
> 
> Frank mentioned that he wants a new API. I have some ideas about it too.
> 
> My take is that drivers should never do reference counting, we have to figure
> out a way for DT access using copy semantics or locks.
> 
> References would still be required for core DT code, but that’s a sane subset.

Yes.  Nothing concrete about implementation was decided at ELC, but this issue
is on my todo list.

-Frank

> 
>> Mark.
>>
>> [1] http://permalink.gmane.org/gmane.linux.drivers.devicetree/153777
> 
> Regards
> 
> — Pantelis
> 
> .
> 

  reply	other threads:[~2016-04-14 16:10 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-14  7:47 [Question] refcount of DT node Masahiro Yamada
2016-04-14  7:47 ` Masahiro Yamada
2016-04-14  8:48 ` Russell King - ARM Linux
2016-04-14  8:48   ` Russell King - ARM Linux
2016-04-14  9:59   ` Mark Rutland
2016-04-14  9:59     ` Mark Rutland
2016-04-14  9:59     ` Mark Rutland
2016-04-14 10:02     ` Pantelis Antoniou
2016-04-14 10:02       ` Pantelis Antoniou
2016-04-14 10:02       ` Pantelis Antoniou
2016-04-14 16:10       ` Frank Rowand [this message]
2016-04-14 16:10         ` Frank Rowand
2016-04-14 16:10         ` Frank Rowand
2016-04-14 17:02       ` Rob Herring
2016-04-14 17:02         ` Rob Herring
2016-04-14 17:02         ` Rob Herring
2016-04-14 18:38     ` Russell King - ARM Linux
2016-04-14 18:38       ` Russell King - ARM Linux
2016-04-14 18:38       ` Russell King - ARM Linux
2016-04-16 15:02       ` Masahiro Yamada
2016-04-16 15:02         ` Masahiro Yamada
2016-04-14 10:10 ` Mark Rutland
2016-04-14 10:10   ` Mark Rutland
2016-04-14 10:10   ` Mark Rutland
2016-04-14 10:40   ` Pantelis Antoniou
2016-04-14 10:40     ` Pantelis Antoniou

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