On Thu, 15 Jan 2026 11:53:19 +0100 Morten Brørup <[email protected]> wrote:
> Stephen, > > As the author of rte_pktmbuf_copy(), can you please review this patch? > > You might find my answers to Konstantin's review informative: > https://patchwork.dpdk.org/project/dpdk/patch/[email protected]/#181914 > > > Venlig hilsen / Kind regards, > -Morten Brørup > > > From: Morten Brørup [mailto:[email protected]] > Sent: Wednesday, 19 November 2025 13.04 > > Requests for copying the at the end of a packet incorrectly returned NULL, > as if copying past the end of a packet. > > When allocating copies from a mempool using pinned external buffers, the > external flag was not preserved in these mbufs. > > Fixes: c3a90c381daa ("mbuf: add a copy routine") > > Signed-off-by: Morten Brørup <[email protected]> > --- > lib/mbuf/rte_mbuf.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/lib/mbuf/rte_mbuf.c b/lib/mbuf/rte_mbuf.c > index 0d931c7a15..e639aff03e 100644 > --- a/lib/mbuf/rte_mbuf.c > +++ b/lib/mbuf/rte_mbuf.c > @@ -675,7 +675,7 @@ rte_pktmbuf_copy(const struct rte_mbuf *m, struct > rte_mempool *mp, > __rte_mbuf_sanity_check(m, 1); > > /* check for request to copy at offset past end of mbuf */ > - if (unlikely(off >= m->pkt_len)) > + if (unlikely(off > m->pkt_len)) > return NULL; It makes more sense to return NULL (as error) rather than creating a 0 length mbuf in this corner case. > mc = rte_pktmbuf_alloc(mp); > @@ -688,8 +688,8 @@ rte_pktmbuf_copy(const struct rte_mbuf *m, struct > rte_mempool *mp, > > __rte_pktmbuf_copy_hdr(mc, m); > > - /* copied mbuf is not indirect or external */ > - mc->ol_flags = m->ol_flags & ~(RTE_MBUF_F_INDIRECT|RTE_MBUF_F_EXTERNAL); > + /* copy flags except indirect and external, and preserve flags of newly > allocated mbuf */ > + mc->ol_flags |= m->ol_flags & > ~(RTE_MBUF_F_INDIRECT|RTE_MBUF_F_EXTERNAL); Should have space in expression. At that point it is a new mbuf (the copy) so offload flags should be clear, not sure what the issue is here. But hadn't expected usage of this function with an external mbuf pool. > > prev = &mc->next; > m_last = mc;
