RE: [PATCH v2 01/10] net/ngbe: fix Rx buffer size in configure register

["Jiawen Wu" <jiawenwu@trustnetic.com>]

On Thursday, February 9, 2023 5:00 PM, Jiawen Wu wrote:
> On Wednesday, February 8, 2023 6:28 PM, Ferruh Yigit wrote:
> > On 2/2/2023 9:21 AM, Jiawen Wu wrote:
> > > When buffer size is less than 1K, round down makes it 0, which is an
> > > error value.
> > >
> > > Fixes: 62fc35e63d0e ("net/ngbe: support Rx queue start/stop")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
> > > ---
> > >  drivers/net/ngbe/ngbe_rxtx.c | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/ngbe/ngbe_rxtx.c
> > > b/drivers/net/ngbe/ngbe_rxtx.c index 9fd24fa444..9a646cb6a7 100644
> > > --- a/drivers/net/ngbe/ngbe_rxtx.c
> > > +++ b/drivers/net/ngbe/ngbe_rxtx.c
> > > @@ -2944,7 +2944,10 @@ ngbe_dev_rx_init(struct rte_eth_dev *dev)
> > >  		 */
> > >  		buf_size = (uint16_t)(rte_pktmbuf_data_room_size(rxq->mb_pool) -
> > >  			RTE_PKTMBUF_HEADROOM);
> > > -		buf_size = ROUND_DOWN(buf_size, 0x1 << 10);
> > > +		if (buf_size < 1024)
> > > +			buf_size = ROUND_UP(buf_size, 0x1 << 10);
> >
> > Back to original problem statement in previous version, can't this
> > cause HW to receive packets exceeding the buffer size?
> >
> > If HW accepts buffer size in multiple of 1K, does this mean any buffer
> > size less than 1K is an error condition for this HW?
> >
> 
> After rechecking the code, the minimum buffer size is limited to 1K by the
> txgbe/ngbe [1].
> I think v1 patch for txgbe is enough.
> 
> [1]
> static int
> txgbe_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info) {
> 	struct rte_pci_device *pci_dev = RTE_ETH_DEV_TO_PCI(dev);
> 	struct txgbe_hw *hw = TXGBE_DEV_HW(dev);
> 
> 	dev_info->min_rx_bufsize = 1024;
> 
> 
> > > +		else
> > > +			buf_size = ROUND_DOWN(buf_size, 0x1 << 10);
> > >  		srrctl |= NGBE_RXCFG_PKTLEN(buf_size);
> > >
> > >  		wr32(hw, NGBE_RXCFG(rxq->reg_idx), srrctl);
> >
> >
> 

Hi Ferruh,

Is my proposal feasible or do I need to send v3 patch for it?