tuntap: simplify error handling in tun_build_skb() (f7053b6c) · Commits · 戴 / test

There's no need to duplicate page get logic in each action. So this patch tries to get page and calculate the offset before processing XDP actions (except for XDP_DROP), and undo them when meet errors (we don't care the performance on errors). This will be used for factoring out XDP logic. Signed-off-by:

Jason Wang <jasowang@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/tun.c

+3 −7

Original line number	Diff line number	Diff line
		@@ -1701,17 +1701,13 @@ static struct sk_buff tun_build_skb(struct tun_struct tun,
		xdp_do_flush_map();
		if (err)
		goto err_redirect;
		rcu_read_unlock();
		local_bh_enable();
		return NULL;
		goto out;
		case XDP_TX:
		get_page(alloc_frag->page);
		alloc_frag->offset += buflen;
		if (tun_xdp_tx(tun->dev, &xdp) < 0)
		goto err_redirect;
		rcu_read_unlock();
		local_bh_enable();
		return NULL;
		goto out;
		case XDP_PASS:
		delta = orig_data - xdp.data;
		len = xdp.data_end - xdp.data;
		@@ -1742,7 +1738,7 @@ static struct sk_buff tun_build_skb(struct tun_struct tun,

		err_redirect:
		put_page(alloc_frag->page);
		err_xdp:
		out:
		rcu_read_unlock();
		local_bh_enable();
		this_cpu_inc(tun->pcpu_stats->rx_dropped);

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