RE: [PATCH v2] net/ice: fix scalar Rx and Tx path segment

["Ye, MingjinX" <mingjinx.ye@intel.com>]

> -----Original Message-----
> From: Zhang, Qi Z <qi.z.zhang@intel.com>
> Sent: 2022年11月10日 18:37
> To: Ye, MingjinX <mingjinx.ye@intel.com>; dev@dpdk.org
> Cc: Yang, Qiming <qiming.yang@intel.com>; stable@dpdk.org; Zhou, YidingX
> <yidingx.zhou@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>; Wu,
> Jingjing <jingjing.wu@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>; Ferruh
> Yigit <ferruh.yigit@intel.com>
> Subject: RE: [PATCH v2] net/ice: fix scalar Rx and Tx path segment
> 
> 
> 
> > -----Original Message-----
> > From: Ye, MingjinX <mingjinx.ye@intel.com>
> > Sent: Wednesday, November 9, 2022 8:56 PM
> > To: dev@dpdk.org
> > Cc: Yang, Qiming <qiming.yang@intel.com>; stable@dpdk.org; Zhou,
> > YidingX <yidingx.zhou@intel.com>; Ye, MingjinX
> > <mingjinx.ye@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>; Lu,
> > Wenzhuo <wenzhuo.lu@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>;
> > Li, Xiaoyun <xiaoyun.li@intel.com>; Ferruh Yigit
> > <ferruh.yigit@intel.com>
> > Subject: [PATCH v2] net/ice: fix scalar Rx and Tx path segment
> >
> > CRC is stripped by the hardware in the scattered Rx path. If the last
> > buffer packet length is '0', the scalar Tx path would send empty
> > buffer that causes the Tx queue to overflow.
> 
> Please separate this patch into two, one for Rx and one for Tx, they are
> independent.
> 
> For the Tx implementation, I think we can move them into tx_prepare where
> is place to check Tx violation.
Thanks for your suggestion, I will provide 2 new patches according to the new
scheme and promote it to the community.
> 
> >
> > This patch adds a judgment for the last buffer length to fix this
> > issue, so that it would free the mbuf associated to the last one if the last
> buffer is empty.
> >
> > Fixes: 6eac0b7fde95 ("net/ice: support advance Rx/Tx")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Mingjin Ye <mingjinx.ye@intel.com>
> >
> > v2:
> > 	* Fix log level in ice_rxtx.c source file.
> > ---
> >  drivers/net/ice/ice_rxtx.c | 53
> > ++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 51 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c
> > index 0a2b0376ac..b181f66aad 100644
> > --- a/drivers/net/ice/ice_rxtx.c
> > +++ b/drivers/net/ice/ice_rxtx.c
> > @@ -2111,6 +2111,10 @@ ice_recv_scattered_pkts(void *rx_queue,
> >  			} else
> >  				rxm->data_len = (uint16_t)(rx_packet_len -
> >
> > RTE_ETHER_CRC_LEN);
> > +		} else if (rx_packet_len == 0) {
> > +			rte_pktmbuf_free_seg(rxm);
> > +			first_seg->nb_segs--;
> > +			last_seg->next = NULL;
> >  		}
> >
> >  		first_seg->port = rxq->port_id;
> > @@ -2903,6 +2907,35 @@ ice_calc_pkt_desc(struct rte_mbuf *tx_pkt)
> >  	return count;
> >  }
> >
> > +/*Check the number of valid mbufs and free the invalid mbufs*/ static
> > +inline uint16_t ice_check_mbuf(struct rte_mbuf *tx_pkt) {
> > +	struct rte_mbuf *txd = tx_pkt;
> > +	struct rte_mbuf *txd_removal = NULL;
> > +	struct rte_mbuf *txd_pre = NULL;
> > +	uint16_t count = 0;
> > +	uint16_t removal = 0;
> > +
> > +	while (txd != NULL) {
> > +		if (removal == 1 || txd->data_len == 0) {
> > +			txd_removal = txd;
> > +			txd = txd->next;
> > +			if (removal == 0) {
> > +				removal = 1;
> > +				txd_pre->next = NULL;
> > +			}
> > +			rte_pktmbuf_free_seg(txd_removal);
> > +		} else {
> > +			++count;
> > +			txd_pre = txd;
> > +			txd = txd->next;
> > +		}
> > +	}
> > +
> > +	return count;
> > +}
> > +
> >  uint16_t
> >  ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t
> > nb_pkts) { @@ -2960,11 +2993,27 @@ ice_xmit_pkts(void *tx_queue,
> > struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
> >  		 * the mbuf data size exceeds max data size that hw allows
> >  		 * per tx desc.
> >  		 */
> > -		if (ol_flags & RTE_MBUF_F_TX_TCP_SEG)
> > +		if (ol_flags & RTE_MBUF_F_TX_TCP_SEG) {
> >  			nb_used = (uint16_t)(ice_calc_pkt_desc(tx_pkt) +
> >  					     nb_ctx);
> > -		else
> > +		} else {
> > +			nb_used = ice_check_mbuf(tx_pkt);
> > +			if (nb_used == 0) {
> > +				PMD_TX_LOG(ERR,
> > +				"Check packets is empty "
> > +				"(port=%d queue=%d)\n",
> > +				txq->port_id, txq->queue_id);
> > +				continue;
> > +			} else if (nb_used < tx_pkt->nb_segs) {
> > +				PMD_TX_LOG(DEBUG,
> > +				"Check packets valid num ="
> > +				"%4u total num = %4u (port=%d
> > queue=%d)\n",
> > +				nb_used, tx_pkt->nb_segs, txq->port_id,
> txq-
> > >queue_id);
> > +				tx_pkt->nb_segs = nb_used;
> > +			}
> >  			nb_used = (uint16_t)(tx_pkt->nb_segs + nb_ctx);
> > +		}
> > +
> >  		tx_last = (uint16_t)(tx_id + nb_used - 1);
> >
> >  		/* Circular ring */
> > --
> > 2.34.1