From: Ilya Matveychikov <matvejchikov@gmail.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 2/2] mbuf: reset nb_segs of chained packet
Date: Thu, 16 Nov 2017 23:15:18 +0400 [thread overview]
Message-ID: <BE4BD981-E63D-48F6-A19E-873FB22ECBA1@gmail.com> (raw)
In-Reply-To: <20171116090155.31419fe3@xeon-e3>
> On Nov 16, 2017, at 9:01 PM, Stephen Hemminger <stephen@networkplumber.org> wrote:
>
> On Thu, 16 Nov 2017 18:05:35 +0400
> Ilya Matveychikov <matvejchikov@gmail.com> wrote:
>
>> Fixes: 139debc42dc0 ("mbuf: move chaining from ip_frag library")
>> Cc: simon.kagstrom@netinsight.net
>>
>> Signed-off-by: Ilya V. Matveychikov <matvejchikov@gmail.com>
>> ---
>> lib/librte_mbuf/rte_mbuf.h | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
>> index ce8a05ddf..2126dc94b 100644
>> --- a/lib/librte_mbuf/rte_mbuf.h
>> +++ b/lib/librte_mbuf/rte_mbuf.h
>> @@ -1828,9 +1828,12 @@ static inline int rte_pktmbuf_chain(struct rte_mbuf *head, struct rte_mbuf *tail
>> head->nb_segs += tail->nb_segs;
>> head->pkt_len += tail->pkt_len;
>>
>> - /* pkt_len is only set in the head */
>> + /* nb_segs and pkt_len are only set in the head */
>> + tail->nb_segs = 1;
>> tail->pkt_len = tail->data_len;
>>
>> + __rte_mbuf_sanity_check(head, 1);
>> +
>> return 0;
>> }
>
> My understanding is that nb_segs and pkt_len are only valid
> in head. For other packets in the chain nb_segs and pkt_len
> can be anything.
So why not to keep them in consistency with multi-seg logic?
I mean that pkt_len/nb_segs for the head always have meaning but for
the rest of chain pkt_len is the same as data_len and nb_segs := 1
next prev parent reply other threads:[~2017-11-16 19:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-16 14:05 Ilya Matveychikov
2017-11-16 17:01 ` Stephen Hemminger
2017-11-16 19:15 ` Ilya Matveychikov [this message]
2017-12-01 16:37 ` Olivier MATZ
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