From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <amwang@redhat.com>
Subject: Re: [Patch net-next] net: clean up skb headers code
Date: Wed, 29 May 2013 14:48:06 +0800
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To: David Miller <davem@davemloft.net>
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On Tue, 2013-05-28 at 23:36 -0700, David Miller wrote:
> From: Cong Wang <amwang@redhat.com>
> Date: Wed, 29 May 2013 14:09:00 +0800
> 
> > commit 1a37e412a0225fcba5587 (net: Use 16bits for *_headers
> > fields of struct skbuff) converts skb->*_header to u16,
> > therefore 1) we could just use 0xFFFFF instead of (__u16) ~0U
> > 2) some #if NET_SKBUFF_DATA_USES_OFFSET is useless now.
> > 
> > 
> > Cc: David S. Miller <davem@davemloft.net>
> > Cc: Simon Horman <horms@verge.net.au>
> > Signed-off-by: Cong Wang <amwang@redhat.com>
> 
> I want to use something that will either break the build or
> automatically work if the type changes again.
> 
> So something like "X = (typeof(X)) ~0U;".

Yeah, this is even better. I will update this patch.

Thanks.