From: Thomas Graf <tgraf@suug.ch>
To: "David S. Miller" <davem@davemloft.net>
Cc: kuznet@ms2.inr.ac.ru, herbert@gondor.apana.org.au, netdev@oss.sgi.com
Subject: Re: [PATCH] NETLINK: Use SKB_MAXORDER to calculate NLMSG_GOODSIZE
Date: Mon, 7 Feb 2005 14:28:30 +0100 [thread overview]
Message-ID: <20050207132830.GZ31837@postel.suug.ch> (raw)
In-Reply-To: <20050206223239.5dc4e325.davem@davemloft.net>
> > > struct sk_buff *nskb;
> > > int header = skb_headroom(skb);
> > > - int copy = (PAGE_SIZE - sizeof(struct sk_buff) -
> > > - sizeof(struct skb_shared_info) - header - 31)&~15;
> > > + int copy = SKB_MAX_ORDER(header + 31, 0);
> > >
> > > /* Too big header? This can happen with IPv6. */
> > > if (copy < 0)
> >
> > Sorry, this is incomplete, we should refetch copy via (skb->end - skb->head) after
> > allocating it. I have to think some more about this first. ;-)
>
> I don't understand, if we alloc_skb(copy) we are guarenteed to have
> "copy" bytes available in the SKB data area.
Yes but don't we waste space in the headroom of the new skb iff the
headroom of the original skb is no aligned to SKB_DATA_ALIGN?
I'll post a new patch without the anyway though.
next prev parent reply other threads:[~2005-02-07 13:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-28 23:03 [PATCH] NETLINK: Use SKB_MAXORDER to calculate NLMSG_GOODSIZE Thomas Graf
2005-01-28 23:22 ` Herbert Xu
2005-01-28 23:40 ` Thomas Graf
2005-02-07 6:27 ` David S. Miller
2005-01-28 23:48 ` Alexey Kuznetsov
2005-01-29 0:21 ` Thomas Graf
2005-01-29 0:27 ` Thomas Graf
2005-02-07 6:32 ` David S. Miller
2005-02-07 13:28 ` Thomas Graf [this message]
2005-02-07 14:27 ` [PATCH] NET: Fix calculation for collapsed skb size Thomas Graf
2005-02-09 4:54 ` David S. Miller
2005-01-29 18:40 ` [PATCH] NETLINK: Use SKB_MAXORDER to calculate NLMSG_GOODSIZE Alexey Kuznetsov
2005-01-29 12:47 ` Thomas Graf
2005-02-06 18:54 ` Thomas Graf
2005-02-06 21:08 ` David S. Miller
2005-02-07 6:25 ` David S. Miller
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