Subject: Re: [PATCH v1 net-next 5/6] net: allow simultaneous SW and HW transmit timestamping

From: Miroslav Lichvar <[email-masked]>
Date: Fri, 28 Apr 2017 10:54:22 +0200

On Wed, Apr 26, 2017 at 08:00:02PM -0400, Willem de Bruijn wrote:
> > diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> > index 81ef53f..42bff22 100644
> > --- a/include/linux/skbuff.h
> > +++ b/include/linux/skbuff.h
> > @@ -3300,8 +3300,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
> >
> >  static inline void sw_tx_timestamp(struct sk_buff *skb)
> >  {
> > -       if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
> > -           !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
> > +       if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
> >                 skb_tstamp_tx(skb, NULL);
> >  }

> > +++ b/net/core/skbuff.c
> > @@ -3874,6 +3874,10 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
> >         if (!sk)
> >                 return;
> >
> > +       if (!hwtstamps && !(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW) &&
> > +           skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)
> > +               return;
> > +
> 
> This check should only happen for software transmit timestamps, so simpler to
> revise the check in sw_tx_timestamp above to
> 
>   if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP &&
> -        !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
> +      (!(skb_shinfo(orig_skb)->tx_flags & SKBTX_IN_PROGRESS)) ||
> +      (skb->sk && skb->sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TX_SWHW)

I'm not sure if this can work. sk_buff.h would need to include sock.h
in order to get the definition of struct sock. Any suggestions?

-- 
Miroslav Lichvar