[PATCH net-next v3 0/2] trace: add tracepoint for tcp_sendmsg_locked()

[Breno Leitao <leitao@debian.org>]

Meta has been using BPF programs to monitor tcp_sendmsg() for years,
indicating significant interest in observing this important
functionality. Adding a proper tracepoint provides a stable API for all
users who need visibility into TCP message transmission.

David Ahern is using a similar functionality with a custom patch[1]. So,
this means we have more than a single use case for this request, and it
might be a good idea to have such feature upstream.

Link: https://lore.kernel.org/all/70168c8f-bf52-4279-b4c4-be64527aa1ac@kernel.org/ [1]

Signed-off-by: Breno Leitao <leitao@debian.org>
---
Changes in v3:
- Fixed identation (Kuniyuki Iwashi)
- Removed duplicated entry in the commit message (Kuniyuki Iwashi)
- Added tcp_sendmsg_locked in bpf_raw_tp_null_args[] (Kuniyuki Iwashi)
- Link to v2: https://lore.kernel.org/r/20250407-tcpsendmsg-v2-0-9f0ea843ef99@debian.org

Changes in v2:
- Change to a full tracepoint inside tcp_sendmsg_locked(), heavily
  inspired in David's patch
- Link to v1: https://lore.kernel.org/r/20250224-tcpsendmsg-v1-1-bac043c59cc8@debian.org

---
Breno Leitao (2):
      net: pass const to msg_data_left()
      trace: tcp: Add tracepoint for tcp_sendmsg_locked()

 include/linux/socket.h     |  2 +-
 include/trace/events/tcp.h | 24 ++++++++++++++++++++++++
 kernel/bpf/btf.c           |  1 +
 net/ipv4/tcp.c             |  2 ++
 4 files changed, 28 insertions(+), 1 deletion(-)
---
base-commit: 1a9239bb4253f9076b5b4b2a1a4e8d7defd77a95
change-id: 20250224-tcpsendmsg-4f0a236751d7

Best regards,
-- 
Breno Leitao <leitao@debian.org>