linux-kernel - Re: [PATCH V3 15/20] cxl: Add a routine to find cxl root decoder on cxl bus using cxl port

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Message-ID: <700072760.81759726504033.JavaMail.epsvc@epcpadp1new>
Date: Mon, 29 Sep 2025 19:10:24 +0530
From: Neeraj Kumar <s.neeraj@...sung.com>
To: Dave Jiang <dave.jiang@...el.com>
Cc: linux-cxl@...r.kernel.org, nvdimm@...ts.linux.dev,
	linux-kernel@...r.kernel.org, gost.dev@...sung.com,
	a.manzanares@...sung.com, vishak.g@...sung.com, neeraj.kernel@...il.com,
	cpgs@...sung.com
Subject: Re: [PATCH V3 15/20] cxl: Add a routine to find cxl root decoder on
 cxl bus using cxl port

On 24/09/25 11:11AM, Dave Jiang wrote:
>
>> +struct cxl_root_decoder *cxl_find_root_decoder_by_port(struct cxl_port *port)
>> +{
>> +	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
>> +	struct device *dev;
>> +
>> +	if (!cxl_root)
>> +		return NULL;
>> +
>> +	dev = device_find_child(&cxl_root->port.dev, NULL, match_root_decoder);
>> +	if (!dev)
>> +		return NULL;
>> +
>> +	/* Release device ref taken via device_find_child() */
>> +	put_device(dev);
>
>Should the caller release the device reference instead?
>
>DJ

Actually caller of this function wants to find root decoder information from cxl_port.
So in order to find root decoder we have used device_find_child() which internally
takes device ref. Therefore, just after finding the appropriate dev, I am releasing
device ref.
Its like taking device ref temporarly and releasing it then and there after finding
proper root decoder.
I believe, Releasing device ref from caller would make it look little out of context.

Regards,
Neeraj