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

[Jason Wang]

On 2018å09æ07æ 01:16, Michael S. Tsirkin wrote:
> On Thu, Sep 06, 2018 at 12:05:20PM +0800, Jason Wang wrote:
> > 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 <jasowang@xxxxxxxxxx>
> True...
>
> > ---
> >   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

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