From: Edward Cree <ecree@amd.com>
To: Paolo Abeni <pabeni@redhat.com>,
Chenyuan Yang <chenyuan0y@gmail.com>,
ecree.xilinx@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: Fri, 25 Jul 2025 11:11:44 +0100 [thread overview]
Message-ID: <de14f60e-b1f0-432c-80b4-a2f0453e0fe2@amd.com> (raw)
In-Reply-To: <045d1ff5-bb20-481d-a067-0a42345ab83d@redhat.com>
On 7/24/25 10:57, Paolo Abeni wrote:
> On 7/23/25 2:32 AM, Chenyuan Yang wrote:
>> The xdp_convert_buff_to_frame() function can return NULL when there is
>> insufficient headroom in the buffer to store the xdp_frame structure
>> or when the driver didn't reserve enough tailroom for skb_shared_info.
>
> AFAIC the sfc driver reserves both enough headroom and tailroom, but
> this is after ebpf run, which in turn could consume enough headroom to
> cause a failure, so I think this makes sense.
Your reasoning seems plausible to me.
However, I think the error path ought to more closely follow the existing
error cases in logging a ratelimited message and calling the tracepoint.
I think the cleanest way to do this would be:
if (unlikely(!xdpf))
err = -ENOBUFS;
else
err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);
so that it can make use of the existing failure path.
Adding the check to efx_xdp_tx_buffers() is also an option.
-ed
next prev parent reply other threads:[~2025-07-25 10:11 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 [this message]
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
2025-07-31 9:14 ` Jesper Dangaard Brouer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=de14f60e-b1f0-432c-80b4-a2f0453e0fe2@amd.com \
--to=ecree@amd.com \
--cc=andrew+netdev@lunn.ch \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=chenyuan0y@gmail.com \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=ecree.xilinx@gmail.com \
--cc=edumazet@google.com \
--cc=hawk@kernel.org \
--cc=john.fastabend@gmail.com \
--cc=kuba@kernel.org \
--cc=linux-net-drivers@amd.com \
--cc=lorenzo@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=sdf@fomichev.me \
--cc=zzjas98@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).