Merge branch 'mptcp-misc-fixes-for-v6-19-rc8'

Matthieu Baerts says:

====================
mptcp: misc fixes for v6.19-rc8

Here are various unrelated fixes:

- Patch 1: when removing an MPTCP in-kernel PM endpoint, always mark the
  corresponding ID as "available". Syzbot found a corner case where it
  is not marked as such. A fix for up to v5.10.

- Patch 2: Linked to the previous patch, the variable name was confusing
  and was probably partly responsible for the issue fixed by patch 1. No
  "Fixes" tag: no need to backport that for the moment, but better to
  avoid confusion now.

- Patch 3: fix all existing kdoc warnings linked to MPTCP code. No
  "Fixes" tag: they were there for a while, and not considered as
  important to backport.

- Patch 4: silence a compiler (false-positive) warning in the selftests.
  No "Fixes" tag: it is a false-positive warning, only seen with some
  versions.
====================

Link: https://patch.msgid.link/20260205-net-mptcp-misc-fixes-6-19-rc8-v2-0-c2720ce75c34@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

5 files changed, 24 insertions, 26 deletions

diff --git a/Documentation/netlink/specs/mptcp_pm.yaml b/Documentation/netlink/specs/mptcp_pm.yaml
index ba30a40b9dbf..39f3facc38e5 100644
--- a/Documentation/netlink/specs/mptcp_pm.yaml
+++ b/Documentation/netlink/specs/mptcp_pm.yaml
@@ -15,6 +15,7 @@ definitions:
     type: enum
     name: event-type
     enum-name: mptcp-event-type
+    doc: Netlink MPTCP event types
     name-prefix: mptcp-event-
     entries:
       -
diff --git a/include/uapi/linux/mptcp_pm.h b/include/uapi/linux/mptcp_pm.h
index c97d060ee90b..fe9863d75350 100644
--- a/include/uapi/linux/mptcp_pm.h
+++ b/include/uapi/linux/mptcp_pm.h
@@ -11,7 +11,7 @@
 #define MPTCP_PM_VER	1
 
 /**
- * enum mptcp_event_type
+ * enum mptcp_event_type - Netlink MPTCP event types
  * @MPTCP_EVENT_UNSPEC: unused event
  * @MPTCP_EVENT_CREATED: A new MPTCP connection has been created. It is the
  *   good time to allocate memory and send ADD_ADDR if needed. Depending on the
diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index b26675054b0d..b5316a6c7d1b 100644
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -1044,26 +1044,23 @@ out_free:
 	return ret;
 }
 
-static bool mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
+static void mptcp_pm_remove_anno_addr(struct mptcp_sock *msk,
 				      const struct mptcp_addr_info *addr,
 				      bool force)
 {
 	struct mptcp_rm_list list = { .nr = 0 };
-	bool ret;
+	bool announced;
 
 	list.ids[list.nr++] = mptcp_endp_get_local_id(msk, addr);
 
-	ret = mptcp_remove_anno_list_by_saddr(msk, addr);
-	if (ret || force) {
+	announced = mptcp_remove_anno_list_by_saddr(msk, addr);
+	if (announced || force) {
 		spin_lock_bh(&msk->pm.lock);
-		if (ret) {
-			__set_bit(addr->id, msk->pm.id_avail_bitmap);
+		if (announced)
 			msk->pm.add_addr_signaled--;
-		}
 		mptcp_pm_remove_addr(msk, &list);
 		spin_unlock_bh(&msk->pm.lock);
 	}
-	return ret;
 }
 
 static void __mark_subflow_endp_available(struct mptcp_sock *msk, u8 id)
@@ -1097,17 +1094,15 @@ static int mptcp_nl_remove_subflow_and_signal_addr(struct net *net,
 					  !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT));
 
 		list.ids[0] = mptcp_endp_get_local_id(msk, addr);
-		if (remove_subflow) {
-			spin_lock_bh(&msk->pm.lock);
-			mptcp_pm_rm_subflow(msk, &list);
-			spin_unlock_bh(&msk->pm.lock);
-		}
 
-		if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) {
-			spin_lock_bh(&msk->pm.lock);
+		spin_lock_bh(&msk->pm.lock);
+		if (remove_subflow)
+			mptcp_pm_rm_subflow(msk, &list);
+		if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW)
 			__mark_subflow_endp_available(msk, list.ids[0]);
-			spin_unlock_bh(&msk->pm.lock);
-		}
+		else /* mark endp ID as available, e.g. Signal or MPC endp */
+			__set_bit(addr->id, msk->pm.id_avail_bitmap);
+		spin_unlock_bh(&msk->pm.lock);
 
 		if (msk->mpc_endpoint_id == entry->addr.id)
 			msk->mpc_endpoint_id = 0;
diff --git a/net/mptcp/token.c b/net/mptcp/token.c
index 5bb924534387..f1a50f367add 100644
--- a/net/mptcp/token.c
+++ b/net/mptcp/token.c
@@ -103,7 +103,7 @@ static void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
  * It creates a unique token to identify the new mptcp connection,
  * a secret local key and the initial data sequence number (idsn).
  *
- * Returns 0 on success.
+ * Return: 0 on success.
  */
 int mptcp_token_new_request(struct request_sock *req)
 {
@@ -146,7 +146,7 @@ int mptcp_token_new_request(struct request_sock *req)
  * the computed token at a later time, this is needed to process
  * join requests.
  *
- * returns 0 on success.
+ * Return: 0 on success.
  */
 int mptcp_token_new_connect(struct sock *ssk)
 {
@@ -241,7 +241,7 @@ found:
  * This function returns the mptcp connection structure with the given token.
  * A reference count on the mptcp socket returned is taken.
  *
- * returns NULL if no connection with the given token value exists.
+ * Return: NULL if no connection with the given token value exists.
  */
 struct mptcp_sock *mptcp_token_get_sock(struct net *net, u32 token)
 {
@@ -288,11 +288,13 @@ EXPORT_SYMBOL_GPL(mptcp_token_get_sock);
  * @s_slot: start slot number
  * @s_num: start number inside the given lock
  *
- * This function returns the first mptcp connection structure found inside the
- * token container starting from the specified position, or NULL.
+ * Description:
+ *   On successful iteration, the iterator is moved to the next position and a
+ *   reference to the returned socket is acquired.
  *
- * On successful iteration, the iterator is moved to the next position and
- * a reference to the returned socket is acquired.
+ * Return:
+ *   The first mptcp connection structure found inside the token container
+ *   starting from the specified position, or NULL.
  */
 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot,
 					 long *s_num)
diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c
index 10f6f99cfd4e..24b4abac8687 100644
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.c
+++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c
@@ -1296,8 +1296,8 @@ void xdisconnect(int fd)
 
 int main_loop(void)
 {
+	struct addrinfo *peer = NULL;
 	int fd = 0, ret, fd_in = 0;
-	struct addrinfo *peer;
 	struct wstate winfo;
 
 	if (cfg_input && cfg_sockopt_types.mptfo) {