netdev - Re: [PATCH net-next 3/3] net: allow to leave the buffer fragmented in skb_cow

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Message-ID: <20131106093028.GA18435@gondor.apana.org.au>
Date:	Wed, 6 Nov 2013 17:30:28 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Mathias Krause <mathias.krause@...unet.com>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Steffen Klassert <steffen.klassert@...unet.com>,
	Dmitry Tarnyagin <dmitry.tarnyagin@...kless.no>,
	netdev@...r.kernel.org
Subject: Re: [PATCH net-next 3/3] net: allow to leave the buffer fragmented
 in skb_cow_data()

On Tue, Nov 05, 2013 at 02:54:11PM +0100, Mathias Krause wrote:
>
> -	/* If skb is cloned or its head is paged, reallocate
> -	 * head pulling out all the pages (pages are considered not writable
> -	 * at the moment even if they are anonymous).
> +	/* If skb is cloned reallocate head pulling out all the pages (pages are
> +	 * considered not writable at the moment even if they are anonymous).
>  	 */

Hang on, you haven't explained why it is OK to write to pages.
What if said page is owned by the virt host or some app?

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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