From 91f8613d95ad8cd99d8baf094806d1ef98bc6380 Mon Sep 17 00:00:00 2001 From: Geliang Tang Date: Tue, 22 Sep 2026 19:06:18 +0800 Subject: [PATCH] bpf: Drop duplicate check_app_limited in tcp_bpf_push Commit c5c37af6ecad9 ("tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES") moved tcp_rate_check_app_limited() inside do_tcp_sendpages(), turning it into a wrapper around tcp_sendmsg_locked(). Later, commit ebf2e8860eea ("tcp_bpf: Inline do_tcp_sendpages as it's now a wrapper around tcp_sendmsg") inlined the wrapper in tcp_bpf_push() with direct tcp_sendmsg_locked() calls, which perform the check on every path that queues data, but kept the outer tcp_rate_check_app_limited() that was previously needed to cover do_tcp_sendpages(). The outer call is now redundant. 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 Signed-off-by: Alexei Starovoitov Reviewed-by: Jiayuan Chen Link: https://patch.msgid.link/1f7dc605b16fc0590f7cbf5a27d57271926c01ce.1790074764.git.tanggeliang@kylinos.cn --- 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 = sge->offset; page = sg_page(sge); - tcp_rate_check_app_limited(sk); retry: msghdr.msg_flags = flags | MSG_SPLICE_PAGES; has_tx_ulp = tls_sw_has_ctx_tx(sk);