Re: [PATCH RFC 4/5] tun: vringfd xmit support.

[Herbert Xu]

Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:
>
> +/* We are done with this skb: put it in the used pile. */
> +static void skb_finished(struct skb_shared_info *sinfo)
> +{
> +       struct skb_shinfo_tun *sht = (void *)(sinfo + 1);
> +
> +       /* FIXME: Race prevention */
> +       vring_used_buffer_atomic(sht->tun->outring, sht->id, sht->len);
> +       vring_wake(sht->tun->outring);
> +
> +       /* Release device. */
> +       dev_put(sht->tun->dev);
> +}

On second thought, this is not going to work.  The network stack
can clone individual pages out of this skb and put it into a new
skb.  Therefore whatever scheme we come up with will either need
to be page-based, or add a flag to tell the network stack that it
can't clone those pages.

Cheers,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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