From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC3DE4A33; Tue, 8 Jul 2025 02:17:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751941075; cv=none; b=V/Lq1TcArwVIBi4UrIL9VMZJ2yW38F0EFcb+UgR2H6IpqLHob+OwxzzgZEtF2md+2Li5NiHEv1tGKh53bw1Ijk62WZZlcxNYkPVF5AT/nS7xPkrAeaJ3uxRGmq828u1qMfluqPfAu9hAV2azGcaSLRdvR6k5PDBn8UEZ+koA2qs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751941075; c=relaxed/simple; bh=CRpOrfSwGL9/Z96Cxl6WO3Wqwa/IZSORWC6BncTNWLM=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ZliQqqeU3Dn/ii+e+naHAE9r3cMLm9hDMLGdCT20MV96G5fBBXMBe556W2DTaUfYjxzw4xE27+xVve/Mf3Ghg6fkQJ4QrY6Db4OmXcoLo4sIPeZESqvnWxB6N5qeRbf8cpdB7vCIFWCFGxct0N1EfXSeE0wmv5NPYhxZ4/3GTEE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ClKxGCTR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ClKxGCTR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E027C4CEE3; Tue, 8 Jul 2025 02:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751941074; bh=CRpOrfSwGL9/Z96Cxl6WO3Wqwa/IZSORWC6BncTNWLM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ClKxGCTRQ7lrIwmIJldjcqO0LFxXnM+M41V5VV5+C695sMWXCPA5+fxbGz230hwTm OX8dvC0EcDBoWDZ73dhI0BuxJt6YKp+Sbw2sK97BrLrdJXSLhhYfYXkLBd4cLILq3Z TPLudXfnf2zyQICkPlS87UqK4MTwYDAnK/abydWuGdy4CwL4geYX1+6BKWPkEitIhV +NqCk7xVp58FPBk6Yh0WPK8RXx98u7KYtoOWQc32fj1bqb9lVu/m3TnlATGGYBgIlj hlQk672zb4SMRJZmlZNUNz4rnVya93azZB2nWr7s8U/BSoVJQhWodfp7RAwcpsD2OY QjPtzx5hUlo4w== Date: Mon, 7 Jul 2025 19:17:42 -0700 From: Jakub Kicinski To: "Song, Yoong Siang" Cc: "David S . Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Jonathan Corbet , Alexei Starovoitov , Daniel Borkmann , "Jesper Dangaard Brouer" , John Fastabend , Stanislav Fomichev , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , "netdev@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" Subject: Re: [PATCH bpf-next 0/2] Clarify and Enhance XDP Rx Metadata Handling Message-ID: <20250707191742.662aeffb@kernel.org> In-Reply-To: References: <20250701042940.3272325-1-yoong.siang.song@intel.com> <20250707135507.29cb55be@kernel.org> <20250707184449.42736a0a@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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.