mptcp: pm: move generic PM helpers to pm.c

Before this patch, the PM code was dispersed in different places:

- pm.c had common code for all PMs

- pm_netlink.c was supposed to be about the in-kernel PM, but also had
  exported common helpers, callbacks used by the different PMs, NL
  events for PM userspace daemon, etc. quite confusing.

- pm_userspace.c had userspace PM only code, but using specific
  in-kernel PM helpers

To clarify the code, a reorganisation is suggested here, only by moving
code around, and (un)exporting functions:

- helpers used from both PMs and not linked to Netlink
- callbacks used by different PMs, e.g. ADD_ADDR management
- some helpers have been marked as 'static'
- protocol.h has been updated accordingly
- (while at it, a needless if before a kfree(), spot by checkpatch in
   mptcp_remove_anno_list_by_saddr(), has been removed)

The code around the PM is now less confusing, which should help for the
maintenance in the long term.

This will certainly impact future backports, but because other cleanups
have already done recently, and more are coming to ease the addition of
a new path-manager controlled with BPF (struct_ops), doing that now
seems to be a good time. Also, many issues around the PM have been fixed
a few months ago while increasing the code coverage in the selftests, so
such big reorganisation can be done with more confidence now.

No behavioural changes intended.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250307-net-next-mptcp-pm-reorg-v1-13-abef20ada03b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index f66c3d28333f..360d8cfa5279 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -996,7 +996,6 @@ bool mptcp_pm_addr_families_match(const struct sock *sk,
 				  const struct mptcp_addr_info *loc,
 				  const struct mptcp_addr_info *rem);
 void mptcp_pm_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
-void mptcp_pm_subflows_chk_stale(const struct mptcp_sock *msk, struct sock *ssk);
 void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side);
 void mptcp_pm_fully_established(struct mptcp_sock *msk, const struct sock *ssk);
 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
@@ -1010,10 +1009,13 @@ void mptcp_pm_add_addr_received(const struct sock *ssk,
 void mptcp_pm_add_addr_echoed(struct mptcp_sock *msk,
 			      const struct mptcp_addr_info *addr);
 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
-bool mptcp_pm_is_init_remote_addr(struct mptcp_sock *msk,
-				  const struct mptcp_addr_info *remote);
+void mptcp_pm_send_ack(struct mptcp_sock *msk,
+		       struct mptcp_subflow_context *subflow,
+		       bool prio, bool backup);
 void mptcp_pm_addr_send_ack(struct mptcp_sock *msk);
-void mptcp_pm_rm_addr_recv(struct mptcp_sock *msk);
+void mptcp_pm_nl_rm_addr(struct mptcp_sock *msk, u8 rm_id);
+void mptcp_pm_rm_subflow(struct mptcp_sock *msk,
+			 const struct mptcp_rm_list *rm_list);
 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
 			       const struct mptcp_rm_list *rm_list);
 void mptcp_pm_mp_prio_received(struct sock *sk, u8 bkup);
@@ -1024,14 +1026,10 @@ int mptcp_pm_mp_prio_send_ack(struct mptcp_sock *msk,
 			      u8 bkup);
 bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 			      const struct mptcp_addr_info *addr);
-void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
 bool mptcp_pm_sport_in_anno_list(struct mptcp_sock *msk, const struct sock *sk);
 struct mptcp_pm_add_entry *
 mptcp_pm_del_add_timer(struct mptcp_sock *msk,
 		       const struct mptcp_addr_info *addr, bool check_id);
-struct mptcp_pm_add_entry *
-mptcp_lookup_anno_list_by_saddr(const struct mptcp_sock *msk,
-				const struct mptcp_addr_info *addr);
 bool mptcp_lookup_subflow_by_saddr(const struct list_head *list,
 				   const struct mptcp_addr_info *saddr);
 bool mptcp_remove_anno_list_by_saddr(struct mptcp_sock *msk,