RE: [PATCH v3 2/4] ethdev: introduce protocol hdr based buffer split

["Wang, YuanX" <yuanx.wang@intel.com>]

Hi 

> -----Original Message-----
> From: Suanming Mou <suanmingm@nvidia.com>
> Sent: Tuesday, September 13, 2022 3:57 PM
> To: Wang, YuanX <yuanx.wang@intel.com>; dev@dpdk.org; NBU-Contact-
> Thomas Monjalon (EXTERNAL) <thomas@monjalon.net>; Ferruh Yigit
> <ferruh.yigit@xilinx.com>; Andrew Rybchenko
> <andrew.rybchenko@oktetlabs.ru>
> Cc: mdr@ashroe.eu; Li, Xiaoyun <xiaoyun.li@intel.com>; Singh, Aman Deep
> <aman.deep.singh@intel.com>; Zhang, Yuying <yuying.zhang@intel.com>;
> Zhang, Qi Z <qi.z.zhang@intel.com>; Yang, Qiming <qiming.yang@intel.com>;
> jerinjacobk@gmail.com; Slava Ovsiienko <viacheslavo@nvidia.com>;
> stephen@networkplumber.org; Ding, Xuan <xuan.ding@intel.com>;
> hpothula@marvell.com; Tang, Yaqi <yaqi.tang@intel.com>; Wenxuan Wu
> <wenxuanx.wu@intel.com>
> Subject: RE: [PATCH v3 2/4] ethdev: introduce protocol hdr based buffer split
> 
> Hi
> 
> > -----Original Message-----
> > From: Yuan Wang <yuanx.wang@intel.com>
> > Sent: Saturday, September 3, 2022 3:10 AM
> > To: dev@dpdk.org; NBU-Contact-Thomas Monjalon (EXTERNAL)
> > <thomas@monjalon.net>; Ferruh Yigit <ferruh.yigit@xilinx.com>; Andrew
> > Rybchenko <andrew.rybchenko@oktetlabs.ru>
> > Cc: mdr@ashroe.eu; xiaoyun.li@intel.com; aman.deep.singh@intel.com;
> > yuying.zhang@intel.com; qi.z.zhang@intel.com; qiming.yang@intel.com;
> > jerinjacobk@gmail.com; Slava Ovsiienko <viacheslavo@nvidia.com>;
> > stephen@networkplumber.org; xuan.ding@intel.com;
> hpothula@marvell.com;
> > yaqi.tang@intel.com; Yuan Wang <yuanx.wang@intel.com>; Wenxuan Wu
> > <wenxuanx.wu@intel.com>
> > Subject: [PATCH v3 2/4] ethdev: introduce protocol hdr based buffer
> > split
> >
> 
> snip
> 
> > @@ -1693,13 +1695,44 @@ rte_eth_rx_queue_check_split(const struct
> > rte_eth_rxseg_split *rx_seg,
> >  		}
> >  		offset += seg_idx != 0 ? 0 : RTE_PKTMBUF_HEADROOM;
> >  		*mbp_buf_size = rte_pktmbuf_data_room_size(mpl);
> > -		length = length != 0 ? length : *mbp_buf_size;
> > -		if (*mbp_buf_size < length + offset) {
> > -			RTE_ETHDEV_LOG(ERR,
> > -				       "%s mbuf_data_room_size %u < %u
> > (segment length=%u + segment offset=%u)\n",
> > -				       mpl->name, *mbp_buf_size,
> > -				       length + offset, length, offset);
> > -			return -EINVAL;
> > +
> > +		int ret =
> > rte_eth_buffer_split_get_supported_hdr_ptypes(port_id, NULL, 0);
> 
> One small question, since the  ptypes == NULL and num == 0, I assume ret
> will always be <=0, right?

The usage of rte_eth_buffer_split_get_supported_hdr_ptypes is the same as rte_eth_dev_get_supported_ptypes.
 In this scenario, the function returns the total number of supported ptypes, or an error code less than 0.

> 
> > +		if (ret <= 0) {
> > +			/* Split at fixed length. */
> > +			length = length != 0 ? length : *mbp_buf_size;
> > +			if (*mbp_buf_size < length + offset) {
> > +				RTE_ETHDEV_LOG(ERR,
> > +					"%s mbuf_data_room_size %u < %u
> > (segment length=%u + segment offset=%u)\n",
> > +					mpl->name, *mbp_buf_size,
> > +					length + offset, length, offset);
> > +				return -EINVAL;
> > +			}
> > +		} else {
> > +			/* Split after specified protocol header. */
> > +			uint32_t ptypes[ret];
> > +			int i;
> > +
> > +			ret =
> > rte_eth_buffer_split_get_supported_hdr_ptypes(port_id, ptypes, ret);
> > +			for (i = 0; i < ret; i++)
> > +				if (ptypes[i] & proto_hdr)
> > +					break;
> > +
> 
> snip