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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Hangbin Liu <liuhangbin@gmail.com>
Cc: netdev@vger.kernel.org, Stefano Brivio <sbrivio@redhat.com>,
	"David S . Miller" <davem@davemloft.net>,
	David Ahern <dsa@cumulusnetworks.com>
Subject: Re: [PATCH net] sit: use ipv6_mod_enabled to check if ipv6 is disabled
Date: Mon, 25 Feb 2019 08:39:27 -0800	[thread overview]
Message-ID: <1dd57d9d-fed2-67b8-ac28-7ef3681eeed2@gmail.com> (raw)
In-Reply-To: <20190225081759.GP10051@dhcp-12-139.nay.redhat.com>



On 02/25/2019 12:17 AM, Hangbin Liu wrote:
> On Sun, Feb 24, 2019 at 08:24:51PM -0800, Eric Dumazet wrote:
>>
>>
>> On 02/24/2019 08:12 PM, Hangbin Liu wrote:
>>> ipv6_mod_enabled() is more safe and gentle to check if ipv6 is disabled
>>> at running time.
>>>
>>
>>
>> Why is it better exactly ?
>>
>> IPv6 can be enabled on the host, but disabled per device
>>
>> /proc/sys/net/ipv6/conf/{name}/disable_ipv6
> 
> Sorry, it looks I didn't make it clear in the commit description.
> This issue only occurs when IPv6 is disabled at boot time as there is
> no IPv6 route entry. Disable ipv6 on specific interface is not affected.
> So check ipv6_mod_enabled() is enough and we don't need to worry about
> the rcu_read_lock or the dev status.
> 
> Should I update the commit description?

Certainly. Are you telling us skb->dev could be NULL here ?

Because rcu_read_lock() should already be asserted.


  reply	other threads:[~2019-02-25 16:39 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-25  4:12 [PATCH net] sit: use ipv6_mod_enabled to check if ipv6 is disabled Hangbin Liu
2019-02-25  4:24 ` Eric Dumazet
2019-02-25  8:17   ` Hangbin Liu
2019-02-25 16:39     ` Eric Dumazet [this message]
2019-02-25 16:57       ` David Ahern
2019-02-26  1:55         ` Hangbin Liu
2019-02-26  2:15           ` David Ahern
2019-02-26  4:08             ` Hangbin Liu
2019-02-26  4:36               ` Eric Dumazet
2019-02-26  1:43       ` Hangbin Liu

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