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From: Kunwu Chan <kunwu.chan@linux.dev>
To: Edward Cree <ecree.xilinx@gmail.com>, Edward Cree <ecree@amd.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Chenyuan Yang <chenyuan0y@gmail.com>,
	andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
	kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net,
	hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me,
	lorenzo@kernel.org
Cc: netdev@vger.kernel.org, linux-net-drivers@amd.com,
	bpf@vger.kernel.org, zzjas98@gmail.com
Subject: Re: [PATCH] sfc: handle NULL returned by xdp_convert_buff_to_frame()
Date: Wed, 30 Jul 2025 15:38:00 +0800	[thread overview]
Message-ID: <0b43ded0-701c-475b-99af-72612a8afc3d@linux.dev> (raw)
In-Reply-To: <4169cfd4-2231-417f-b091-d8fa2f73f176@gmail.com>

On 2025/7/28 22:28, Edward Cree wrote:
> On 25/07/2025 13:38, Kunwu Chan wrote:
>> Proposed refinement:
> ...
>>           if (net_ratelimit())
>>               netif_err(efx, rx_err, efx->net_dev,
>> -                  "XDP TX failed (%d)\n", err);
>> +                  "XDP TX failed (%d)%s\n", err,
>> +                  err == -ENOBUFS ? " [frame conversion]" : "");
> Unnecessary, since efx_xdp_tx_buffers() never returns ENOBUFS.

You're correct that efx_siena_xdp_tx_buffers() never returns -ENOBUFS,

and xdp_convert_buff_to_frame() returns NULL on failure.

Whether we need a log to distinguish where the errors come from?

  +   if (unlikely(!xdpf))

  +          err = -ENOBUFS;

  +   else

  +      err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);

  -    err = efx_siena_xdp_tx_buffers(efx, 1, &xdpf, true);
       if (unlikely(err != 1)) {
           efx_siena_free_rx_buffers(rx_queue, rx_buf, 1);
           if (net_ratelimit())
               netif_err(efx, rx_err, efx->net_dev,
-                  "XDP TX failed (%d)\n", err);
+                  "XDP TX failed (%d)%s\n", err,
+                  err == -ENOBUFS ? " [xdp_convert_buff_to_frame]" : 
"efx_siena_xdp_tx_buffers");

Just a personal thought.


>
>>           channel->n_rx_xdp_bad_drops++;
>> -        trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
>> +        if (err != -ENOBUFS)
>> +            trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
> Why prevent the tracepoint in this case??
You're correct, my mistake.

-- 
Thanks,
        TAO.
---
“Life finds a way.”


  reply	other threads:[~2025-07-30  7:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-23  0:32 [PATCH] sfc: handle NULL returned by xdp_convert_buff_to_frame() Chenyuan Yang
2025-07-24  9:57 ` Paolo Abeni
2025-07-25 10:11   ` Edward Cree
2025-07-25 12:38     ` Kunwu Chan
2025-07-26 19:56       ` Chenyuan Yang
2025-07-28 14:28       ` Edward Cree
2025-07-30  7:38         ` Kunwu Chan [this message]
2025-07-31  9:14     ` Jesper Dangaard Brouer

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