RE: [PATCH 2/2] net/ice: fix TSO with big segments

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Tuesday, September 19, 2023 10:05 PM
> To: dev@dpdk.org
> Cc: ktraynor@redhat.com; mkp@redhat.com; dexia.li@jaguarmicro.com;
> stable@dpdk.org; Yang, Qiming <qiming.yang@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>; Kevin Liu <kevinx.liu@intel.com>
> Subject: [PATCH 2/2] net/ice: fix TSO with big segments
> 
> Packets to be segmented with TSO are usually larger than MTU.
> Plus, a single segment for the whole packet may be used: in OVS case, an
> external rte_malloc'd buffer is used for packets received from vhost-user
> ports.
> 
> Before this fix, TSO packets were dropped by net/ice with the following
> message:
> 2023-09-18T13:34:31.064Z|00020|dpdk(pmd-
> c31/id:22)|ERR|ice_prep_pkts():
> 	INVALID mbuf: bad data_len=[2962]
> 
> Remove the check on data_len.
> 
> Besides, logging an error level message in a datapath function may slow
> down the whole application. It is better not to log anything.
> 
> Fixes: ccf33dccf7aa ("net/ice: check illegal packet sizes")
> Cc: stable@dpdk.org
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
> Note: there may be some followup patch later, as some additional check has
> been added in ice_prep_pkts.
> For context, see:
> http://inbox.dpdk.org/dev/CAJFAV8yOa3ShkVdEXHfnmOEmUTwV3e75Bu9U3
> OqpNc5usTt3Rw@mail.gmail.com/T/#u
> 
> ---
>  drivers/net/ice/ice_rxtx.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c index
> 64c4486b4b..80c4284200 100644
> --- a/drivers/net/ice/ice_rxtx.c
> +++ b/drivers/net/ice/ice_rxtx.c
> @@ -3685,9 +3685,6 @@ ice_prep_pkts(__rte_unused void *tx_queue,
> struct rte_mbuf **tx_pkts,
>  	int i, ret;
>  	uint64_t ol_flags;
>  	struct rte_mbuf *m;
> -	struct ice_tx_queue *txq = tx_queue;
> -	struct rte_eth_dev *dev = &rte_eth_devices[txq->port_id];
> -	uint16_t max_frame_size = dev->data->mtu + ICE_ETH_OVERHEAD;
> 
>  	for (i = 0; i < nb_pkts; i++) {
>  		m = tx_pkts[i];
> @@ -3704,11 +3701,8 @@ ice_prep_pkts(__rte_unused void *tx_queue,
> struct rte_mbuf **tx_pkts,
>  			return i;
>  		}
> 
> -		/* check the data_len in mbuf */
> -		if (m->data_len < ICE_TX_MIN_PKT_LEN ||
> -			m->data_len > max_frame_size) {
> +		if (m->pkt_len < ICE_TX_MIN_PKT_LEN) {

+1 

>  			rte_errno = EINVAL;
> -			PMD_DRV_LOG(ERR, "INVALID mbuf: bad
> data_len=[%hu]", m->data_len);

is it still worth to keep a debug level log here ? and it's better to unify the logging method in the same function.

>  			return i;
>  		}
> 
> --
> 2.41.0