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tuntap: simplify error handling in tun_build_skb()

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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>
This commit is contained in:
Jason Wang
2018-09-12 11:17:02 +08:00
committed by David S. Miller
parent 291aeb2b1d
commit f7053b6ccb
1 changed files with 3 additions and 7 deletions
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10
drivers/net/tun.c
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@ -1701,17 +1701,13 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
xdp_do_flush_map(); xdp_do_flush_map();
if (err) if (err)
goto err_redirect; goto err_redirect;
rcu_read_unlock(); goto out;
local_bh_enable();
return NULL;
case XDP_TX: case XDP_TX:
get_page(alloc_frag->page); get_page(alloc_frag->page);
alloc_frag->offset += buflen; alloc_frag->offset += buflen;
if (tun_xdp_tx(tun->dev, &xdp) < 0) if (tun_xdp_tx(tun->dev, &xdp) < 0)
goto err_redirect; goto err_redirect;
rcu_read_unlock(); goto out;
local_bh_enable();
return NULL;
case XDP_PASS: case XDP_PASS:
delta = orig_data - xdp.data; delta = orig_data - xdp.data;
len = xdp.data_end - 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: err_redirect:
put_page(alloc_frag->page); put_page(alloc_frag->page);
err_xdp: out:
rcu_read_unlock(); rcu_read_unlock();
local_bh_enable(); local_bh_enable();
this_cpu_inc(tun->pcpu_stats->rx_dropped); this_cpu_inc(tun->pcpu_stats->rx_dropped);