From: Jason Wang <jasowang@redhat.com>
Date: Wed, 12 Sep 2018 11:17:02 +0800
Subject: tuntap: simplify error handling in tun_build_skb()
Patch-mainline: v4.20-rc1
Git-commit: f7053b6ccb65a36fdfed6ad92b808464839f0eb6
References: bsc#1109837
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/tun.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1656,17 +1656,13 @@ static struct sk_buff *tun_build_skb(str
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;
@@ -1697,7 +1693,7 @@ static struct sk_buff *tun_build_skb(str
err_redirect:
put_page(alloc_frag->page);
-err_xdp:
+out:
rcu_read_unlock();
local_bh_enable();
this_cpu_inc(tun->pcpu_stats->rx_dropped);