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Commit f7053b6c authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

tuntap: simplify error handling in tun_build_skb() 



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: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 291aeb2b

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);