linux-kernel - Re: [PATCH v3 15/16] usb: musb: da8xx: Use devm in probe

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Message-ID: <56FDA4A0.6080106@lechnology.com>
Date:	Thu, 31 Mar 2016 17:28:48 -0500
From:	David Lechner <david@...hnology.com>
To:	Bin Liu <b-liu@...com>, petr@...ix.com,
	sergei.shtylyov@...entembedded.com, David.Laight@...LAB.COM,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Sekhar Nori <nsekhar@...com>,
	Kevin Hilman <khilman@...nel.org>,
	Kishon Vijay Abraham I <kishon@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Lee Jones <lee.jones@...aro.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>,
	"moderated list:ARM PORT" <linux-arm-kernel@...ts.infradead.org>,
	"open list:USB SUBSYSTEM" <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v3 15/16] usb: musb: da8xx: Use devm in probe

On 03/31/2016 05:21 PM, Bin Liu wrote:

>> -	glue = kzalloc(sizeof(*glue), GFP_KERNEL);
>> +	glue = devm_kzalloc(&pdev->dev, sizeof(*glue), GFP_KERNEL);
>>   	if (!glue) {
>>   		dev_err(&pdev->dev, "failed to allocate glue context\n");
>> -		goto err0;
>> +		return -ENOMEM;
>>   	}
>>
>> -	clk = clk_get(&pdev->dev, "usb20");
>> +	clk = devm_clk_get(&pdev->dev, "usb20");
>>   	if (IS_ERR(clk)) {
>>   		dev_err(&pdev->dev, "failed to get clock\n");
>> -		ret = PTR_ERR(clk);
>> -		goto err3;
>> +		return PTR_ERR(clk);
>
> memory leak due to not kfree(glue).

It is my understanding that since glue is allocated with devm_kzalloc(), 
that if the probe function returns and error, glue and everything else 
allocated with devm_* will be automatically freed.

If this is not the case, wouldn't devm_kfree() be the appropriate 
function instead?


>> @@ -576,8 +569,6 @@ static int da8xx_remove(struct platform_device *pdev)
>>   	platform_device_unregister(glue->musb);
>>   	usb_phy_generic_unregister(glue->phy);
>>   	clk_disable(glue->clk);
>> -	clk_put(glue->clk);
>> -	kfree(glue);
>
> Doesn't match with $subject, I'd put them into a seperate patch.


I disagree. Since these are now automatically freed because of changes 
in the probe function, these changes belong in the same patch.