Re: [PATCH, v2] net: release dst entry in dev_hard_start_xmit()

[Eric Dumazet <dada1@cosmosbay.com>]

Jarek Poplawski a écrit :
> On Tue, May 19, 2009 at 09:44:14PM +0200, Eric Dumazet wrote:
>> David Miller a écrit :
>>> From: Eric Dumazet <dada1@cosmosbay.com>
>>> Date: Tue, 12 May 2009 21:26:35 +0200
>>>
>>>> [PATCH] net: release dst entry in dev_hard_start_xmit()
>>>  ...
>>>> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
>>> Applied, thanks Eric.
>>>
>>> Eric, please followup and double-check the pppoe paths
>>> that Jarek mentioned.  I never saw that fully resolved.
>>>
>> [PATCH] ppp: unset IFF_XMIT_DST_RELEASE in ppp_setup()
>>
>> Jarek pointed pppoe can call back dev_queue_xmit(), and might need
>> skb->dst, so its safer to unset IFF_XMIT_DST_RELEASE on ppp devices.
> 
> Hmm... Of course, this patch looks OK to me, but actually my main
> concern was more general. We avoid adding such flags for each "real"
> dev, but if so IMHO it would be safer to generally add them to all
> "virtual" devs - needed or not. You prefer to do this only where
> necessary, but it's not always clear if it's omitted on purpose or
> by chance. So, now I'm wondering about xen-netfront - needlessly I
> hope ;-)
> 

This is the deal in fact, tracking all valid uses, and I'll check this.

Another path would have to set the flag only for fast devices (Gb and 10Gb)