netdev - Re: [PATCH 4/7 v2] net: ethernet: i825xx: Fix platform_get

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Message-ID: <39363858-995c-eea4-070e-b21a7ac49bec@gmail.com>
Date:   Tue, 5 Dec 2017 11:04:55 +0530
From:   Arvind Yadav <arvind.yadav.cs@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     wg@...ndegger.com, mkl@...gutronix.de, michal.simek@...inx.com,
        opendmb@...il.com, f.fainelli@...il.com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH 4/7 v2] net: ethernet: i825xx: Fix platform_get_irq's
 error checking

Hi David,


On Monday 04 December 2017 11:55 PM, David Miller wrote:
> From: Arvind Yadav <arvind.yadav.cs@...il.com>
> 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.

~arvind