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 581D7BE6C; Tue, 8 Jul 2025 01:44:52 +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=1751939092; cv=none; b=rFpDCq1S1ZGrOf/cb2Q8JQTjsdb8KadWvYcLjO4qQZMvaPqg3X2o1v1vSvN2xtGbjZr2ZL5AGsxwA0S6Wv1hDriojK/OpXTyCCOVybcWxebympptXsEKQoUl4IjGKJX/ISjUREf0TcNENbW1xXDqVc9GaVXoRdJrsHKNRjTegnA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751939092; c=relaxed/simple; bh=6m1lzxS6q2RHVwpfjunpRF/H7GBK31qlq/09C2C2JuU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=K5HgqH2veMCpAewD6jGnV/uC9jH5Am4W09gBCpjW2qMqtD3AFZIUorMrkE/H0ojjdLim7IzVu9cjDfhGiHr+rAA5CfoUgusqR090CSPo/HzqdG45q623N1vQvzKip+ORIqdpXUwG/WpCpv0bztb1OwmtIZcUXGKcDndRzCOodZc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XrVPM4bJ; 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="XrVPM4bJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BE80C4CEE3; Tue, 8 Jul 2025 01:44:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751939091; bh=6m1lzxS6q2RHVwpfjunpRF/H7GBK31qlq/09C2C2JuU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XrVPM4bJNNe419JvqzI7qLZr3/wbwqIF+y8BR4guOS/jTnVYlVlZI96S74q/3MXOs 2EVVejkaL3ljsAINLrY2MgCZ/alac+fnzz7e1vvETqdRfquwb+t4xMQW1QgkClGIpn 3oBVnGAQciecwyUhkuAiNsvqWIvrGA96tFtrfRhqiztMj143COvUv/pvNXWv6QDWwn 7VFLLqe+Bj9X/1aGngKxCmyx0VJr9LM7/bHlhDichAFXjnHGqztM2A9kyMyVYpkgdj vaFDm+HWHIC0wsb7dHHPhXXa0Hl8nkF9Oob8VGlDco65IwKHrwqIRKq0cmQEv12sVe oQAlHI+EQy4nQ== Date: Mon, 7 Jul 2025 18:44:49 -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: <20250707184449.42736a0a@kernel.org> In-Reply-To: References: <20250701042940.3272325-1-yoong.siang.song@intel.com> <20250707135507.29cb55be@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 01:34:13 +0000 Song, Yoong Siang wrote: > >For normal XDP my understanding is that its the driver's responsibility > >to move the "reserved" stuff out of place before presenting the frame to > >program. > > Is it means that driver needs to move out the "reserved" stuff before XDP program > and then move back the stuff after XDP program for certain situation, like XDP_PASS? 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.