Re: request_irq() return value

[Lukas Jelinek <info@kernel-api.org>]

Hello,

> Hello,
> 
> 	I'm looking at the source code of different drivers and wondering about 
> request_irq() return value. It is used mostly in 'open' routine of struct 
> net_device. If request_irq() fails some drivers return -EAGAIN, some -EBUSY 
> and some the return value of request_irq(). Is this intentional? Sample 
> drivers code:
> 

I think the most suitable value for this case is -EBUSY. The reason is
that this type of failure is usually permanent and unrecoverable. But
other people may have a different opinion and thus they prefer -EAGAIN
(which is intended for temporary failures) or something else.

Lukas


> 8139cp.c:
> static int cp_open (struct net_device *dev) {
>         ...
>         rc = request_irq(dev->irq, cp_interrupt, SA_SHIRQ, dev->name, dev);
>         if (rc)
>                 goto err_out_hw;
>         ...
> err_out_hw:
>         ...
>         return rc;
> }
> 
> 3c359.c:
> static int xl_open(struct net_device *dev){
>         ...
>         if(request_irq(dev->irq, &xl_interrupt, SA_SHIRQ , "3c359", dev)) {
>                 return -EAGAIN;
>         }
>         ...
> }
> 
> Besides request_irq() is arch dependent so depending on arch it has different 
> set of possible return values. So ... does the return value matter or I 
> misunderstood something here?
> 
> Regards,
> 
> 	Mariusz
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