From nobody Sat Sep 26 11:49:00 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8D012442FD4; Thu, 17 Sep 2026 08:36:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789634226; cv=none; b=oY8/fBaF70OUq8D2G8wTIIcWqfLu8Wl62uM0mUY92HilCnsCuojlBxN91WdbecJjSSdioFMkyq1+s6iBg5DjN7rRAHb7pcm0B2BpzANQ1ImyMnIhKiQxXtYtb2FIfZkWAx+naSVq//hzxstUTEVX3zmJyM8++V3XiFnIZptUMVg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789634226; c=relaxed/simple; bh=9FeaKZWi5iQOkFBE2tpEl9kMwPNQJRYAfnZLWehMj30=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=kS9uGrgN8jAkDFY46TcV6n6X9Rqsx1E4yyhRhbnk3AIL/BuD2UVEXybv0o7UVOs/znNhL8/Y8YAWbXwWyUCXFsRK8AxgpvQYsmhhHigo59OeBOlbI+yY/KYMom/BjLapw72XKkoIyGeG9mRZH6Ra7yUcCYVD9CDB3nLtnDlWGms= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cWOSGRo5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cWOSGRo5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 033C81F000FF; Thu, 17 Sep 2026 08:36:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789634206; bh=ymAdn1uTwYrM1RdKi+vWWG9q1gx1PN4qRudV/xEDgB0=; h=From:To:Cc:Subject:Date; b=cWOSGRo5NGfxnaDr3eUZn3GEFLA9LJ/drcncv2xEpZ0161ckk/wJyahKQ9c056Zgq jKM5xbkxRDciMGswjN4YpAF+Tj3eugjkn2u679RDAP+uuTJGLL4QYUjcW3wfvAaxmh Fy9NnBMDUTwjw31/RKsmfFUbwqP2FCKcbk8AmwcnRUSsAEL4Hn5qmsrw3a0DTuQ2e+ cN8z0elhM3sJKCk3EWefK9v89V4l6U3lE0lQfNrRy4J7Y8rrY33GBo2hHPUC+yEJye ySKcE9ppojd/Ldd0XVEeRaJkKM4IZwvgsh8njuBVcQJPHrYMLTvqjkMLeths47s0Nf 6zDqtRzm6xibQ== From: Geliang Tang To: John Fastabend , Jakub Sitnicki , Jiayuan Chen , Eric Dumazet , Neal Cardwell , Kuniyuki Iwashima , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Simon Horman , Matthieu Baerts , Mat Martineau Cc: Geliang Tang , netdev@vger.kernel.org, bpf@vger.kernel.org, mptcp@lists.linux.dev Subject: [PATCH bpf-next v3] bpf: drop duplicate check_app_limited in tcp_bpf_push Date: Thu, 17 Sep 2026 16:36:34 +0800 Message-ID: <85d9a0f138fa024354edde023a05f9d07b6ac87a.1789633546.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang Before commit c5c37af6ecad9 ("tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES"), do_tcp_sendpages() did not call tcp_rate_check_app_limited() internally, so callers needed an explicit tcp_rate_check_app_limited() to cover it. That commit replaced do_tcp_sendpages() with direct tcp_sendmsg_locked() calls, which perform the check on every path that queues data. The outer call became redundant but was left in place. The site changed here, tcp_bpf_push(), holds the socket lock and invokes tcp_sendmsg_locked() on every iteration. The early-return paths in tcp_sendmsg_locked() that skip tcp_rate_check_app_limited() -- the MSG_ZEROCOPY allocation failure and MSG_FASTOPEN branches -- return without queueing any MSG_SPLICE_PAGES data, so there is no functional consequence from omitting the outer check. A potential benefit of this change is that it facilitates future reuse of tcp_bpf_push() for sockmap support in protocols beyond TCP, such as MPTCP. Since tcp_rate_check_app_limited() is TCP-specific while sendmsg_locked() is a generic interface in struct proto_ops, this change allows us to switch to different protocols via sk->sk_socket->ops->sendmsg_locked() without carrying protocol-specific assumptions. Signed-off-by: Geliang Tang --- Note: This patch was originally part of my ongoing "MPTCP sockmap support" series [1] (patch 5). Matthieu suggested converting it to a fix and sending it directly to netdev. Removing the redundant tcp_rate_check_app_limited() call benefits my subsequent MPTCP work: in patch 3 of that series, I implement an MPTCP-specific mptcp_rate_check_app_limited() function and call it in mptcp_sendmsg_locked(). This allows me to reuse tcp_bpf_push() by simply replacing tcp_sendmsg_locked() with sk->sk_socket->ops->sendmsg_locked(), without carrying protocol-specific assumptions. v3: - send this patch separately to bpf as Jakub suggested. - update the commit log as bot+bpf-ci suggested. v2: - drop the "Fixes" tags and update the prefixes and commit logs as Jiayuan suggested. - https://patchwork.kernel.org/project/netdevbpf/cover/cover.1789469930.gi= t.tanggeliang@kylinos.cn/ v1: - https://patchwork.kernel.org/project/netdevbpf/cover/cover.1789368148.gi= t.tanggeliang@kylinos.cn/ [1] MPTCP sockmap support https://lore.kernel.org/mptcp/b5f9e8d7-b738-1df6-3b5e-1d54cbbc663c@gmail.co= m/T/#t --- net/ipv4/tcp_bpf.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 2e234d155b5e..d5fcf3ce4861 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -108,7 +108,6 @@ static int tcp_bpf_push(struct sock *sk, struct sk_msg = *msg, u32 apply_bytes, off =3D sge->offset; page =3D sg_page(sge); =20 - tcp_rate_check_app_limited(sk); retry: msghdr.msg_flags =3D flags | MSG_SPLICE_PAGES; has_tx_ulp =3D tls_sw_has_ctx_tx(sk); --=20 2.53.0