netdev - Re: several packets in a single buffer in Rx

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Message-ID: <BANLkTi=aBLPX7OMKi=sMhT81x-2f6Ci6sQ@mail.gmail.com>
Date:	Mon, 16 May 2011 15:59:10 +0300
From:	Emmanuel Grumbach <egrumbach@...il.com>
To:	Michał Mirosław <mirqus@...il.com>
Cc:	netdev@...r.kernel.org, linux-wireless@...r.kernel.org,
	Johannes Berg <johannes@...solutions.net>,
	"Guy, Wey-Yi" <wey-yi.w.guy@...el.com>, guy.cohen@...el.com
Subject: Re: several packets in a single buffer in Rx

2011/5/16 Michał Mirosław <mirqus@...il.com>:
> 2011/5/16 Emmanuel Grumbach <egrumbach@...il.com>:
>> I would like to be able to deliver the same page several times to the
>> stack without having the stack consume it before the last time I
>> deliver it.
>> Of course I would like to avoid cloning it.
>
> Just do get_page() on the page having another packet in it before
> passing skb up.
>

I can see the path:
__kfree_skb -> skb_release_all -> skb_release_data -> put_page
put_page will free the page iff the _count variable reaches 0. Of course,
_count is incremented by get_page.

I will give it try.

I understand that this will work regardless the order given to
alloc_pages right ?

Thanks
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