[Intel-wired-lan] [PATCH net v3 3/6] igb: XDP extack message on error

[Sven Auhagen]

On Wed, Nov 11, 2020 at 11:35:44AM +0100, Paul Menzel wrote:
> Dear Sven,
> 
> 
> Am 11.11.20 um 11:10 schrieb Sven Auhagen:
> > On Wed, Nov 11, 2020 at 08:11:46AM +0100, Paul Menzel wrote:
> 
> > > Am 19.10.20 um 10:05 schrieb sven.auhagen at voleatech.de:
> > > > From: Sven Auhagen <sven.auhagen at voleatech.de>
> > > > 
> > > > Add an extack error message when the RX buffer size is too small
> > > > for the frame size.
> > > > 
> > > > Suggested-by: Maciej Fijalkowski <maciej.fijalkowski at intel.com>
> > > > Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski at intel.com>
> > > > Acked-by: Maciej Fijalkowski <maciej.fijalkowski at intel.com>
> > > > Signed-off-by: Sven Auhagen <sven.auhagen at voleatech.de>
> > > > ---
> > > >    drivers/net/ethernet/intel/igb/igb_main.c | 12 +++++++-----
> > > >    1 file changed, 7 insertions(+), 5 deletions(-)
> > > > 
> > > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> > > > index 0a9198037b98..088f9ddb0093 100644
> > > > --- a/drivers/net/ethernet/intel/igb/igb_main.c
> > > > +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> > > > @@ -2824,20 +2824,22 @@ static int igb_setup_tc(struct net_device *dev, enum tc_setup_type type,
> > > >    	}
> > > >    }
> > > > -static int igb_xdp_setup(struct net_device *dev, struct bpf_prog *prog)
> > > > +static int igb_xdp_setup(struct net_device *dev, struct netdev_bpf *bpf)
> > > >    {
> > > >    	int i, frame_size = dev->mtu + IGB_ETH_PKT_HDR_PAD;
> > > >    	struct igb_adapter *adapter = netdev_priv(dev);
> > > > +	struct bpf_prog *prog = bpf->prog, *old_prog;
> > > >    	bool running = netif_running(dev);
> > > > -	struct bpf_prog *old_prog;
> > > >    	bool need_reset;
> > > >    	/* verify igb ring attributes are sufficient for XDP */
> > > >    	for (i = 0; i < adapter->num_rx_queues; i++) {
> > > >    		struct igb_ring *ring = adapter->rx_ring[i];
> > > > -		if (frame_size > igb_rx_bufsz(ring))
> > > > +		if (frame_size > igb_rx_bufsz(ring)) {
> > > > +			NL_SET_ERR_MSG_MOD(bpf->extack, "The RX buffer size is too small for the frame size");
> 
> > just to verify, NL_SET_ERR_MSG_MOD does not take any variable arguments
> > for the text to print.
> 
> Ah, Jesper remarked that too. Can the macro be extended?

It probably can be not as part of this patch series.

> 
> > What seems to be the common practice is to add a second log line
> > with netdev_warn to print out the sizes.
> > 
> > Is that what you are looking for?
> 
> Yes, though it sounds to cumbersome. So, yes, that’d be great for me, but up
> to you, if you think it’s useful.
> 

Let me add a netdev warn here so this patch can move forward
and the information is available.

Best
Sven

> 
> Kind regards,
> 
> Paul
> 
> 
> > > Could you please also add both size values to the error message?
> > > 
> > > >    			return -EINVAL;
> > > > +		}
> > > >    	}
> > > >    	old_prog = xchg(&adapter->xdp_prog, prog);
> > > > @@ -2869,7 +2871,7 @@ static int igb_xdp(struct net_device *dev, struct netdev_bpf *xdp)
> > > >    {
> > > >    	switch (xdp->command) {
> > > >    	case XDP_SETUP_PROG:
> > > > -		return igb_xdp_setup(dev, xdp->prog);
> > > > +		return igb_xdp_setup(dev, xdp);
> > > >    	default:
> > > >    		return -EINVAL;
> > > >    	}
> > > > @@ -6499,7 +6501,7 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
> > > >    			struct igb_ring *ring = adapter->rx_ring[i];
> > > >    			if (max_frame > igb_rx_bufsz(ring)) {
> > > > -				netdev_warn(adapter->netdev, "Requested MTU size is not supported with XDP\n");
> > > > +				netdev_warn(adapter->netdev, "Requested MTU size is not supported with XDP. Max frame size is %d\n", max_frame);
> > > >    				return -EINVAL;
> > > >    			}
> > > >    		}
> > > > 
> > > 
> > > 
> > > Kind regards,
> > > 
> > > Paul
> > > 
> > > 
> > > PS: For commit message summaries, statements with verbs in imperative mood
> > > are quite common [1].
> > > 
> > > > igb: Print XDP extack error on too big frame size
> > > 
> > > 
> > > [1]: https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchris.beams.io%2Fposts%2Fgit-commit%2F&data=04%7C01%7Csven.auhagen%40voleatech.de%7C832ea50c701b4d89fd5508d8862d8c92%7Cb82a99f679814a7295344d35298f847b%7C0%7C0%7C637406877489969478%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ITPcipxk%2Bg%2FR0QRssfiF5lm1K3mGJsB5wFkdF3SqiA0%3D&reserved=0