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

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Date:	Fri, 1 Apr 2016 09:56:44 -0500
From:	Bin Liu <b-liu@...com>
To:	David Lechner <david@...hnology.com>
CC:	<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

Hi,

On Thu, Mar 31, 2016 at 05:28:48PM -0500, David Lechner wrote:
> 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.

Ah, right.

> 
> 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.
> 
Ok.

Signed-off-by: Bin Liu <b-liu@...com>

Regards,
-Bin.