2014-10-20 12:45, Walukiewicz, Miroslaw:
> > > /* fields to support TX offloads */
> > > - union {
> > > - uint16_t l2_l3_len; /**< combined l2/l3 lengths as single var
> > */
> > > - struct {
> > > - uint16_t l3_len:9; /**< L3 (IP) Header Length. */
> > > - uint16_t l2_len:7; /**< L2 (MAC) Header Length.
> > */
> > > + /* two bytes - l2/l3 len for compatibility (endian issues)
> > > + * two bytes - reseved for alignment
> > > + * two bytes - l4 len (TCP/UDP) header len
> > > + * two bytes - TCP tso segment size
> > > + */
> > > + struct {
> > > + union {
> > > + uint16_t l2_l3_len; /**< combined l2/l3 len */
> > > + struct {
> > > + uint16_t l3_len:9; /**< L3 (IP) Header */
> > > + uint16_t l2_len:7; /**< L2 (MAC) Header */
> > > + };
> > > };
> >
> > Why nesting these fields in an anonymous structure?
>
> I want to keep a source compatibility with non-TSO applications using that
> field for example IP checksum computing by NIC.
> Keeping this structure anonymous I do not require changes in old
> applications that do not need TSO support.
>
> The second argument is that in original patch extending the rte_mbuf to 128
> bytes made by Bruce the author made this structure anonymous and I follow
> this assumption too.
Excuse me, maybe I missed something, but I still don't understand why you are
embedding the union into a struct?
--
Thomas
