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Subject: Re: [RFC PATCH v3 3/9] software_node: Fix failure to hold refcount in
 software_node_get_next_child
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     Sakari Ailus <sakari.ailus@iki.fi>, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, linux.walleij@linaro.org,
        prabhakar.mahadev-lad.rj@bp.renesas.com,
        heikki.krogerus@linux.intel.com, dmitry.torokhov@gmail.com,
        laurent.pinchart+renesas@ideasonboard.com,
        kieran.bingham+renesas@ideasonboard.com, jacopo+renesas@jmondi.org,
        robh@kernel.org, davem@davemloft.net, linux@rasmusvillemoes.dk,
        sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
        pmladek@suse.com, mchehab@kernel.org, tian.shu.qiu@intel.com,
        bingbu.cao@intel.com, sakari.ailus@linux.intel.com,
        yong.zhi@intel.com, rafael@kernel.org, gregkh@linuxfoundation.org,
        kitakar@gmail.com, dan.carpenter@oracle.org
References: <20201019225903.14276-1-djrscally@gmail.com>
 <20201019225903.14276-4-djrscally@gmail.com>
 <20201020133148.GB843@valkosipuli.retiisi.org.uk>
 <c1a7beba-faff-e06d-1517-5b30d777b252@gmail.com>
 <20201021093321.GM4077@smile.fi.intel.com>
From:   Dan Scally <djrscally@gmail.com>
Message-ID: <d8f3880e-1b4c-b9dc-7bb2-cb8b7658263e@gmail.com>
Date:   Wed, 21 Oct 2020 10:56:01 +0100
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On 21/10/2020 10:33, Andy Shevchenko wrote:
> On Wed, Oct 21, 2020 at 12:25:28AM +0100, Dan Scally wrote:
>> On 20/10/2020 14:31, Sakari Ailus wrote:
>>> On Mon, Oct 19, 2020 at 11:58:57PM +0100, Daniel Scally wrote:
>>>> +	return software_node_get(&c->fwnode);
>>> I believe similarly, the function should drop the reference to the previous
>>> node, and not expect the caller to do this. The OF equivalent does the
>>> same.
>> I think I prefer it this way myself, since the alternative is having to
>> explicitly call *_node_get() on a returned child if you want to keep it
>> but also keep iterating. But I agree that it's important to take a
>> consistent approach. I'll add that too; this will mean
>> swnode_graph_find_next_port() and
>> software_node_graph_get_next_endpoint() in patch 4 of this series will
>> need changing slightly to square away their references.
> What about ACPI case? Does it square?
ACPI version doesn't handle references at all; neither puts() the old
nor gets() the new child node.