[dpdk-dev] [PATCH] mbuf: fix for incomplete nb_segs types change

[Olivier MATZ]

On Tue, Nov 14, 2017 at 06:09:35AM +0100, Thomas Monjalon wrote:
> > > >> Update types of variables to correspond to nb_segs type change from
> > > >> uint8_t to uint16_t.
> > > >> 
> > > >> Fixes: 97cb466d65c9 ("mbuf: use 2 bytes for port and nb segments")
> > > >> Cc: olivier.matz at 6wind.com
> > > >> 
> > > >> Signed-off-by: Ilya V. Matveychikov <matvejchikov at gmail.com>
> > Acked-by: Olivier Matz <olivier.matz at 6wind.com>
> 
> Is there a real benefit to get it in 17.11?

Without this patch:

- cloning a mbuf with more than 255 segments will create an mbuf with an
  invalid number of segments.

- chaining mbufs with rte_pktmbuf_chain() will return an error if the
  resulting mbuf has more than 255 segments.

> Is there a risk?

It is not so critical, since manipulating mbufs with a large number of
segments is a very specific use case.

But the risk seems low, I think we can put it in 17.11.

Olivier