Subject: Re: [PATCH net-next 1/2] ipmr: restrict mroute "queue full" warning
 to related error values
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20170621175811.16940-1-julien@arista.com>
 <20170623.133947.433422648753848462.davem@davemloft.net>
From: Julien Gomes <julien@arista.com>
Message-ID: <bc8a9605-2df7-821f-5103-e9acb4482f3a@arista.com>
Date: Fri, 23 Jun 2017 10:52:26 -0700
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On 06/23/2017 10:39 AM, David Miller wrote:

> From: Julien Gomes <julien@arista.com>
> Date: Wed, 21 Jun 2017 10:58:10 -0700
>
>> When sending a cache report on mroute_sk, mroute will emit a
>> "pending queue full" warning for every error value returned by
>> sock_queue_rcv_skb().
>> This warning can be misleading, for example on the EPERM error value
>> that sk_filter() can return.
>>
>> Restricting this warning to only ENOMEM or ENOBUFS seems more
>> appropriate.
>>
>> Signed-off-by: Julien Gomes <julien@arista.com>
> Incorrect, no other error codes are possible.
>
> We never attach a socket filter to these kernel internal sockets,
> therefore sk_filter() is not even applicable in this analysis.
>
> Therefore, -ENOBUFS and -ENOMEM are the only errors we can ever see
> returned from sock_queue_rcv_skb().
>
> This goes for your second patch as well.

Up to now I would agree, but now that cache reports are also sent
through Netlink, wouldn't it make sense to allow the user of mroute_sk
to attach a filter to it in order to not receive cache reports on it?

I agree this is not crucial in any way, but this could be a way to let
the user program choose whether it receives the reports through one
of the mediums, and not inevitably both.

-- 
Julien Gomes