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From: Jakub Kicinski <kuba@kernel.org>
To: "Song, Yoong Siang" <yoong.siang.song@intel.com>
Cc: "David S . Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	"Jesper Dangaard Brouer" <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Stanislav Fomichev <sdf@fomichev.me>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	KP Singh <kpsingh@kernel.org>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>,
	Shuah Khan <shuah@kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	"linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH bpf-next 0/2] Clarify and Enhance XDP Rx Metadata Handling
Date: Mon, 7 Jul 2025 19:17:42 -0700	[thread overview]
Message-ID: <20250707191742.662aeffb@kernel.org> (raw)
In-Reply-To: <IA3PR11MB92545C3B2CD5778EE24244C1D84EA@IA3PR11MB9254.namprd11.prod.outlook.com>

On Tue, 8 Jul 2025 02:06:11 +0000 Song, Yoong Siang wrote:
>> Why would the driver need to move it back?
>> On XDP_PASS an skb is constructed, so the metadata should
>> be transferred to the skb. There is no need to copy it back
>> as a prepend.  
> 
> I said so because I thought need to put back the timestamp
> as prepend and then point skb_shared_hwtstamps.netdev_data to it
> to support the ndo_get_tstamp().

No need, the timestamps are set in shared info directly.
There are multiple drivers which use the metadata prepend
method, so I'm pretty sure it should work.

  reply	other threads:[~2025-07-08  2:17 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-01  4:29 [PATCH bpf-next 0/2] Clarify and Enhance XDP Rx Metadata Handling Song Yoong Siang
2025-07-01  4:29 ` [PATCH bpf-next 1/2] doc: clarify XDP Rx metadata layout and bpf_xdp_adjust_meta usage Song Yoong Siang
2025-07-01  4:29 ` [PATCH bpf-next 2/2] selftests/bpf: Enhance XDP Rx Metadata Handling Song Yoong Siang
2025-07-01 16:31   ` Stanislav Fomichev
2025-07-02  2:23     ` Song, Yoong Siang
2025-07-02  3:55       ` Song, Yoong Siang
2025-07-02 15:18         ` Stanislav Fomichev
2025-07-02 15:56           ` Song, Yoong Siang
2025-07-02 16:04             ` Stanislav Fomichev
2025-07-02 16:17               ` Song, Yoong Siang
2025-07-07 20:55 ` [PATCH bpf-next 0/2] Clarify and " Jakub Kicinski
2025-07-08  1:34   ` Song, Yoong Siang
2025-07-08  1:44     ` Jakub Kicinski
2025-07-08  2:06       ` Song, Yoong Siang
2025-07-08  2:17         ` Jakub Kicinski [this message]
2025-07-08  2:32           ` Song, Yoong Siang

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