Re: [PATCH 1/2] misc/pvpanic: Fix error handling in 'pvpanic_pci_probe()'

[Christophe JAILLET]

Le 17/05/2021 à 10:01, Andy Shevchenko a écrit :
> On Sun, May 16, 2021 at 04:36:55PM +0200, Christophe JAILLET wrote:
> > There is no error handling path in the probe function.
> > Switch to managed resource so that errors in the probe are handled easily
> > and simplify the remove function accordingly.
>
> Yes, that's what I suggested earlier to another contributor.
>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>
> Thanks!
>
> P.S. You may consider the following things as well:
>   1) converting to use pci_set_drvdata() / pci_get_drvdata()

I can send a patch for that if you want.
But it looks really low value for a driver that is already very short 
and clean.

>   2) providing devm_pvpanic_probe() [via devm_add_action() /
>      devm_add_action_or_reset()]

I don't follow you here.
The goal would be to avoid the remove function and "record" the needed 
action directly in the probe?

If this is it, I would only see an unusual pattern and a harder to 
follow logic.

Did I miss something?
What would be the benefit?

CJ

> > Fixes: db3a4f0abefd ("misc/pvpanic: add PCI driver")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/misc/pvpanic/pvpanic-pci.c | 9 +++------
> >   1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/misc/pvpanic/pvpanic-pci.c b/drivers/misc/pvpanic/pvpanic-pci.c
> > index 9ecc4e8559d5..046ce4ecc195 100644
> > --- a/drivers/misc/pvpanic/pvpanic-pci.c
> > +++ b/drivers/misc/pvpanic/pvpanic-pci.c
> > @@ -78,15 +78,15 @@ static int pvpanic_pci_probe(struct pci_dev *pdev,
> >   	void __iomem *base;
> >   	int ret;
> >   
> > -	ret = pci_enable_device(pdev);
> > +	ret = pcim_enable_device(pdev);
> >   	if (ret < 0)
> >   		return ret;
> >   
> > -	base = pci_iomap(pdev, 0, 0);
> > +	base = pcim_iomap(pdev, 0, 0);
> >   	if (!base)
> >   		return -ENOMEM;
> >   
> > -	pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
> > +	pi = devm_kmalloc(&pdev->dev, sizeof(*pi), GFP_ATOMIC);
> >   	if (!pi)
> >   		return -ENOMEM;
> >   
> > @@ -107,9 +107,6 @@ static void pvpanic_pci_remove(struct pci_dev *pdev)
> >   	struct pvpanic_instance *pi = dev_get_drvdata(&pdev->dev);
> >   
> >   	pvpanic_remove(pi);
> > -	iounmap(pi->base);
> > -	kfree(pi);
> > -	pci_disable_device(pdev);
> >   }
> >   
> >   static struct pci_driver pvpanic_pci_driver = {
> > --
> > 2.30.2