From: "Timo Teräs" <timo.teras@iki.fi>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] ip_gre: include route header_len in max_headroom calculation
Date: Sat, 20 Mar 2010 16:47:28 +0200 [thread overview]
Message-ID: <4BA4E000.1030206@iki.fi> (raw)
In-Reply-To: <4BA4C2ED.9090701@iki.fi>
Timo Teräs wrote:
> Herbert Xu wrote:
>> On Sat, Mar 20, 2010 at 02:27:58PM +0200, Timo Teras wrote:
>>> diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
>>> index f47c9f7..f78402d 100644
>>> --- a/net/ipv4/ip_gre.c
>>> +++ b/net/ipv4/ip_gre.c
>>> @@ -810,11 +810,13 @@ static netdev_tx_t ipgre_tunnel_xmit(struct
>>> sk_buff *skb, struct net_device *dev
>>> tunnel->err_count = 0;
>>> }
>>>
>>> - max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen;
>>> + max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen +
>>> rt->u.dst.header_len;
>>>
>>> if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
>>> (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
>>> struct sk_buff *new_skb = skb_realloc_headroom(skb,
>>> max_headroom);
>>> + if (max_headroom > dev->needed_headroom)
>>> + dev->needed_headroom = max_headroom;
>>
>> Are you sure about this? LL_RESERVED_SPACE already includes
>> dev->needed_headroom so won't this get bigger each time?
>
> Whoops. Must've been after-midnight issue. And not noticed since the
> max_headroom won't change many times.
>
> dev->needed_headroom should be compared against
> gre_hlen+rt->u.dst.header_len.
> I'll send a fixed patch in a jiffy.
Actually, isn't the above right?
max_headroom is calculated with LL_RESERVED_SPACE of the tdev, which
is the interface to which the gre packet is being sent to, not the
gre interface. Thus, max_headroom won't include gre devices
previous needed_headroom.
- Timo
next prev parent reply other threads:[~2010-03-20 14:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-20 12:27 [PATCH] ip_gre: include route header_len in max_headroom calculation Timo Teras
2010-03-20 12:37 ` Herbert Xu
2010-03-20 12:43 ` Timo Teräs
2010-03-20 14:47 ` Timo Teräs [this message]
2010-03-20 15:00 ` Herbert Xu
2010-03-22 4:26 ` David Miller
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