Subject: Re: [ath9k-devel] [PATCH 1/3] ath9k: Decrease skb size to fit into
 one page.
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Ben Greear <greearb@candelatech.com>
Cc: "Luis R. Rodriguez" <lrodriguez@atheros.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	"ath9k-devel@venema.h4ckr.net" <ath9k-devel@venema.h4ckr.net>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
In-Reply-To: <4D2791BD.7050502@candelatech.com>
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Date: Fri, 07 Jan 2011 23:26:11 +0100
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Sender: linux-wireless-owner@vger.kernel.org

Le vendredi 07 janvier 2011 à 14:20 -0800, Ben Greear a écrit :
> On 0
> > Using skb_copy() is wrong then, since it makes a copy (order-1
> > allocations)
> >
> > It should use :
> >   skb_alloc( actual_size_of_frame  not the 3840 thing ...)
> >   copy(data)
> 
> We need the extra stuff copied too I think (like skb->cb).
> 
> If you could provide a bit more complete example code, I'll be happy
> to test it...

take a random drivers/net using copybreak ... say ... tg3.c

lines 4785

len = length_of_the_current_frame
copy_skb = netdev_alloc_skb(...,  len); 
// allocates exact required size not a byte more....
...
skb_copy_from_linear_data(skb, copy_skb->data, len);
...
skb_put(skb, len);
...