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

From: Sergei Shtylyov
Date: Wed Dec 06 2017 - 07:19:36 EST


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