bpf: Export more helpers for mptcp_userspace_pm_addr test

The mptcp_userspace_pm_addr bpf_iter should be invoked under holding the
msk pm lock, so spin_lock_bh() and spin_unlock_bh() are needed in BPF
program to hold or release the msk pm lock. And bpf_ipv6_addr_v4mapped()
helper is also needed by the mptcp_userspace_pm_addr bpf_iter selftest
program.

This patch adds the corresponding BPF wrappers for these helpers and adds
them to the mptcp common kfunc_set.

Signed-off-by: Geliang Tang <[email protected]>
Message-Id: <ea7e5fe9651149f3f0eb09fbd70f7942d3049b8b.1730953242.git.tanggeliang@kylinos.cn>

net/mptcp/bpf.c

@@ -326,6 +326,24 @@ __bpf_kfunc static void bpf_mptcp_sock_release(struct mptcp_sock *msk)
 	WARN_ON_ONCE(!sk || !refcount_dec_not_one(&sk->sk_refcnt));
 }
 
+__bpf_kfunc static void bpf_spin_lock_bh(spinlock_t *lock)
+{
+	spin_lock_bh(lock);
+}
+
+__bpf_kfunc static void bpf_spin_unlock_bh(spinlock_t *lock)
+{
+	spin_unlock_bh(lock);
+}
+
+__bpf_kfunc static bool bpf_ipv6_addr_v4mapped(const struct mptcp_addr_info *a)
+{
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	return ipv6_addr_v4mapped(&a->addr6);
+#endif
+	return false;
+}
+
 __bpf_kfunc struct mptcp_subflow_context *
 bpf_mptcp_subflow_ctx_by_pos(const struct mptcp_sched_data *data, unsigned int pos)
 {
@@ -353,6 +371,9 @@ BTF_ID_FLAGS(func, bpf_iter_mptcp_userspace_pm_addr_next, KF_ITER_NEXT | KF_RET_
 BTF_ID_FLAGS(func, bpf_iter_mptcp_userspace_pm_addr_destroy, KF_ITER_DESTROY)
 BTF_ID_FLAGS(func, bpf_mptcp_sock_acquire, KF_ACQUIRE | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_mptcp_sock_release, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_spin_lock_bh)
+BTF_ID_FLAGS(func, bpf_spin_unlock_bh)
+BTF_ID_FLAGS(func, bpf_ipv6_addr_v4mapped)
 BTF_KFUNCS_END(bpf_mptcp_common_kfunc_ids)
 
 static const struct btf_kfunc_id_set bpf_mptcp_common_kfunc_set = {