Hi Olivier,

-----Original Message-----
From: Olivier Matz [mailto:olivier.matz@6wind.com]
Sent: Tuesday, January 16, 2018 6:43 PM
To: Wang, Xiao W <redacted>
Cc: yliu@fridaylinux.org; thomas@monjalon.net; Bie, Tiwei
[off-list ref]; dev@dpdk.org; stephen@networkplumber.org;
maxime.coquelin@redhat.com
Subject: Re: [dpdk-dev] [PATCH v10 3/5] net: add a helper for making RARP
packet

Hi Xiao,

On Tue, Jan 16, 2018 at 09:43:43AM +0000, Wang, Xiao W wrote:

quoted

Hi Olivier,

quoted

You can also use rte_pktmbuf_append() to check for the tailroom and
update data_len/pkt_len:

	m = rte_pktmbuf_alloc();

I just realized that if we let this function to allocate mbuf, it may restrict this api's applicability.
E.g. the caller just has a mbuf, without a mempool.
How do you think?

quoted

quoted

	if (m == NULL)
		return NULL;
	eth_hdr = rte_pktmbuf_append(m, RARP_PKT_SIZE);

When data_len is not enough, we need to rte_pktmbuf_append(m,

RARP_PKT_SIZE - m->data_len);

Sorry, I don't get your point here.

I mean we just need to extend the data_len by "RARP_PKT_SIZE - m->data_len" when the room is not big enough.

BRs,
Xiao