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

[Paul Menzel]

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.auha...@voleatech.de:
From: Sven Auhagen <sven.auha...@voleatech.de>

Add an extack error message when the RX buffer size is too small
for the frame size.

Suggested-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
Signed-off-by: Sven Auhagen <sven.auha...@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?

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.


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]: 
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