Re: [PATCH 4/7 v2] net: ethernet: i825xx: Fix platform_get_irq's error checking

[Sergei Shtylyov]

On 12/05/2017 06:49 PM, David Miller wrote:

> > > From: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
> > > Date: Mon,  4 Dec 2017 23:18:20 +0530
> > >
> > > > @@ -120,9 +120,10 @@ static int sni_82596_probe(struct platform_device
> > > > *dev)
> > > >    	netdevice->dev_addr[5] = readb(eth_addr + 0x06);
> > > >    	iounmap(eth_addr);
> > > >    -	if (!netdevice->irq) {
> > > > +	if (netdevice->irq <= 0) {
> > > >    		printk(KERN_ERR "%s: IRQ not found for i82596 at 0x%lx\n",
> > > >    			__FILE__, netdevice->base_addr);
> > > > +		retval = netdevice->irq ? netdevice->irq : -ENODEV;
> > > >    		goto probe_failed;
> > > >    	}
> > > Ok, thinking about this some more...
> > >
> > > It is impossible to use platform_get_irq() without every single call
> > > site having this funny:
> > >
> > > 	ret = val ? val : -ENODEV;
> > >
> > > sequence.
> > >
> > > This is unnecessary duplication and it is also error prone, so I
> > > really think this logic belongs in platform_get_irq() itself.  It can
> > > convert '0' to -ENODEV and that way we need no special logic in the
> > > callers at all.
> > platform_get_irq() will return 0 only for sparc, If sparc initialize
> > platform
> > data irq[PROMINTR_MAX] as zero. Otherwise platform_get_irq() will
> > never return
> > 0. It will return either IRQ number or error (as negative number). But
> > I am getting
> > review comment by reviewer/maintainer in other subsystem to add check
> > for
> > zero. So I have done same changes here. Please correct me if i am
> > wrong.
>
> If you make the change that I suggest, you instead can check for

   I assume such change is needed only for the SPARC-specific section of 
platform_get_irq()?

> '-ENODEV' to mean no IRQ.

   No specific error check is needed, just irq < 0 check should be enough...
Also, looking at platform_get_irq(), -ENXIO should be returned in this case.

MBR, Sergei