From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] return the right retcode when add a unreachable route
Date: Tue, 08 Jul 2014 19:33:57 -0700 (PDT)
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From: lucien xin <lucien.xin@gmail.com>
Date: Wed, 9 Jul 2014 09:51:02 +0800

> On Wed, Jul 9, 2014 at 2:49 AM, Cong Wang <cwang@twopensource.com> wrote:
>> On Sun, Jul 6, 2014 at 4:01 AM, Xin Long <lucien.xin@gmail.com> wrote:
>>
>> This would potentially break user-space applications.
> 
> yes, you are right. if I only handle the -ESRCH , like:
> 
> -       return __fib_lookup(net, flp, res);
> +
> +       err = __fib_lookup(net, flp, res);
> +       if(err == -ESRCH)
> +               return -ENETUNREACH;
> +
> +       return err;
> 
> I think it will be ok, after all, it looks confused that err is *No
> such process* when add a route.

It doesn't matter, if applications want to work on all kernels they
will test whatever error code is being provided now.

Therefore, by changing it you will break those applications.