[dpdk-dev] [PATCH] mbuf: remove redundant line in rte_pktmbuf_attach

[Ananyev, Konstantin]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Ilya Matveychikov
> Sent: Saturday, January 21, 2017 3:08 PM
> To: Yigit, Ferruh <ferruh.yigit at intel.com>
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] mbuf: remove redundant line in rte_pktmbuf_attach
> 
> 
> > On Jan 20, 2017, at 4:08 PM, Ferruh Yigit <ferruh.yigit at intel.com> wrote:
> >
> > On 1/20/2017 12:19 AM, Ilya Matveychikov wrote:
> >> mi->next will be assigned to NULL few lines later, trivial patch
> >>
> >> Signed-off-by: Ilya V. Matveychikov <matvejchikov at gmail.com>
> >> ---
> >> lib/librte_mbuf/rte_mbuf.h | 1 -
> >> 1 file changed, 1 deletion(-)
> >>
> >> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> >> index ead7c6e..5589d54 100644
> >> --- a/lib/librte_mbuf/rte_mbuf.h
> >> +++ b/lib/librte_mbuf/rte_mbuf.h
> >> @@ -1139,7 +1139,6 @@ static inline void rte_pktmbuf_attach(struct rte_mbuf *mi, struct rte_mbuf *m)
> >> 	mi->buf_addr = m->buf_addr;
> >> 	mi->buf_len = m->buf_len;
> >>
> >> -	mi->next = m->next;
> >
> > Do you know why attaching mbuf is not supporting multi-segment?

This is supported, but you have to do it segment by segment.
Actually  rte_pktmbuf_clone() does that.
Konstantin


> > Perhaps this can be documented in function comment, as one of the "not
> > supported" items.
> 
> No, I don’t know. For my application I’ve found that nb_segs with it’s limit in 256 segments is very annoying and I’ve decided not to use
> DPDK functions that dealt with nb_segs… But it is not about the rte_pktmbuf_attach() function and the patch.
> 
> > Also, should we check mi->next before overwriting, in case it is not NULL?
> >
> >> 	mi->data_off = m->data_off;
> >> 	mi->data_len = m->data_len;
> >> 	mi->port = m->port;
> >>
> >
> 
> I don’t know. It depends of the usage. Will someone needs to chain two chains of mbuf?