Re: [PATCH v8] tcp: move seq_to_tap update to when frame is queued

[Stefano Brivio <sbrivio@redhat.com>]

On Wed, 5 Jun 2024 09:59:58 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Tue, Jun 04, 2024 at 11:30:20PM +0200, Stefano Brivio wrote:
> > On Tue,  4 Jun 2024 14:29:08 -0400
> > Jon Maloy <jmaloy@redhat.com> wrote:
> >   
> > > +/**
> > > + * tcp_revert_seq() - Revert affected conn->seq_to_tap after failed transmission
> > > + * @conns:       Array of connection pointers corresponding to queued frames
> > > + * @frames:      Two-dimensional array containing queued frames with sub-iovs
> > > + * @num_frames:  Number of entries in the two arrays to be compared
> > > + */
> > > +static void tcp_revert_seq(struct tcp_tap_conn **conns, struct iovec (*frames)[TCP_NUM_IOVS],
> > > +			   int num_frames)
> > > +{
> > > +	int i;
> > > +
> > > +	for (i = 0; i < num_frames; i++) {
> > > +		struct tcp_tap_conn *conn = conns[i];
> > > +		struct tcphdr *th = frames[i][TCP_IOV_PAYLOAD].iov_base;
> > > +		uint32_t seq = ntohl(th->seq);
> > > +
> > > +		if (SEQ_LE(conn->seq_to_tap, seq))
> > > +			continue;  
> > 
> > See:
> >   https://archives.passt.top/passt-dev/Zkr_4LkjDImgFqSi@zatzit
> >   https://archives.passt.top/passt-dev/ZlkrBFkxliCCT3st@zatzit
> > 
> > about this if (SEQ_LE) ... continue;  
> 
> As Jon mentioned in Monday's call, this looks weird in isolation but
> makes sense after the change in the second patch.

Ah, oops, sorry, you're right, I forgot about that.

-- 
Stefano