linux-kernel - Re: [PATCH 1/3] PCI/pwrctrl: Fix device leak at registration

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Message-ID: <aH99cmBkOwCOkIZk@hovoldconsulting.com>
Date: Tue, 22 Jul 2025 14:00:50 +0200
From: Johan Hovold <johan@...nel.org>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: Johan Hovold <johan+linaro@...nel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Manivannan Sadhasivam <mani@...nel.org>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH 1/3] PCI/pwrctrl: Fix device leak at registration

On Tue, Jul 22, 2025 at 11:05:26AM +0100, Jonathan Cameron wrote:
> On Mon, 21 Jul 2025 17:36:07 +0200
> Johan Hovold <johan+linaro@...nel.org> wrote:

> Perhaps time for 
> DEFINE_FREE(put_pdev, struct platform_device *, if (_T) put_device(&_T->dev));
> 
> then...
> 
> > ---
> >  drivers/pci/bus.c | 14 +++++++++-----
> >  1 file changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
> > index 69048869ef1c..0394a9c77b38 100644
> > --- a/drivers/pci/bus.c
> > +++ b/drivers/pci/bus.c
> > @@ -362,11 +362,15 @@ void pci_bus_add_device(struct pci_dev *dev)
> >  	 * before PCI client drivers.
> >  	 */
> >  	pdev = of_find_device_by_node(dn);
> > -	if (pdev && of_pci_supply_present(dn)) {
> > -		if (!device_link_add(&dev->dev, &pdev->dev,
> > -				     DL_FLAG_AUTOREMOVE_CONSUMER))
> > -			pci_err(dev, "failed to add device link to power control device %s\n",
> > -				pdev->name);
> 
> 	struct platform_device *pdev __free(put_pdev) =
> 		of_find_device_by_node(dn);
> > +	if (pdev) {
> > +		if (of_pci_supply_present(dn)) {
> > +			if (!device_link_add(&dev->dev, &pdev->dev,
> > +					     DL_FLAG_AUTOREMOVE_CONSUMER)) {
> > +				pci_err(dev, "failed to add device link to power control device %s\n",
> > +					pdev->name);
> > +			}
> > +		}
> > +		put_device(&pdev->dev);
> 
> and no need for any explicit put.
> 
> We already do this extensively in some subsystems (e.g. CXL) and it
> greatly simplifies code.

No, I'm no fan of those kind of changes which I find leads to less
readable code (e.g. with those in-code declarations).

Johan