[PATCH RFC 4/5] tun: vringfd xmit support.
Herbert Xu
herbert at gondor.apana.org.au
Sun Apr 6 22:13:44 PDT 2008
Rusty Russell <rusty at rustcorp.com.au> 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 at gondor.apana.org.au>
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