Re: [PATCH net-next 05/11] tuntap: tweak on the path of non-xdp case in tun_build_skb()

On 2018年09月07日 01:16, Michael S. Tsirkin wrote:

On Thu, Sep 06, 2018 at 12:05:20PM +0800, Jason Wang wrote:

quoted

If we're sure not to go native XDP, there's no need for several things
like bh and rcu stuffs.

Signed-off-by: Jason Wang <redacted>

True...

quoted

---
  drivers/net/tun.c | 9 ++++++---
  1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index f8cdcfa392c3..389aa0727cc6 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -1675,10 +1675,12 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
  	 * of xdp_prog above, this should be rare and for simplicity
  	 * we do XDP on skb in case the headroom is not enough.
  	 */
-	if (hdr->gso_type || !xdp_prog)
+	if (hdr->gso_type || !xdp_prog) {
  		*skb_xdp = 1;
-	else
-		*skb_xdp = 0;
+		goto build;
+	}
+
+	*skb_xdp = 0;
  
  	local_bh_disable();
  	rcu_read_lock();

@@ -1724,6 +1726,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
  	rcu_read_unlock();
  	local_bh_enable();
  
+build:

But this is spaghetti code. Please just put common
code into functions and call them, don't goto.

Ok, will do this.

Thanks

quoted

  	skb = build_skb(buf, buflen);
  	if (!skb) {
  		skb = ERR_PTR(-ENOMEM);
-- 
2.17.1

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