mptcp: pm: initialize and release mptcp_pm_ops

Add a struct mptcp_pm_ops pointer "ops" in struct mptcp_pm_data, and two
functions mptcp_pm_initialize() and mptcp_pm_release(), to set and release
this pointer. mptcp_pm_initialize() is invoked in mptcp_pm_data_reset(),
while mptcp_pm_release() is invoked in mptcp_destroy_common().

Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

net/mptcp/pm.c

@@ -603,8 +603,10 @@ bool mptcp_pm_addr_families_match(const struct sock *sk,
 
 void mptcp_pm_data_reset(struct mptcp_sock *msk)
 {
+	const char *path_manager = mptcp_get_path_manager(sock_net((struct sock *)msk));
 	u8 pm_type = mptcp_get_pm_type(sock_net((struct sock *)msk));
 	struct mptcp_pm_data *pm = &msk->pm;
+	int ret;
 
 	pm->add_addr_signaled = 0;
 	pm->add_addr_accepted = 0;
@@ -614,6 +616,12 @@ void mptcp_pm_data_reset(struct mptcp_sock *msk)
 	pm->rm_list_rx.nr = 0;
 	WRITE_ONCE(pm->pm_type, pm_type);
 
+	rcu_read_lock();
+	ret = mptcp_pm_initialize(msk, mptcp_pm_find(path_manager));
+	rcu_read_unlock();
+	if (ret)
+		return;
+
 	if (pm_type == MPTCP_PM_TYPE_KERNEL) {
 		bool subflows_allowed = !!mptcp_pm_get_subflows_max(msk);
 
@@ -706,3 +714,33 @@ void mptcp_pm_unregister(struct mptcp_pm_ops *pm)
 	list_del_rcu(&pm->list);
 	spin_unlock(&mptcp_pm_list_lock);
 }
+
+int mptcp_pm_initialize(struct mptcp_sock *msk, struct mptcp_pm_ops *pm)
+{
+	if (!pm)
+		pm = &mptcp_in_kernel_pm;
+
+	if (!bpf_try_module_get(pm, pm->owner))
+		return -EBUSY;
+
+	msk->pm.ops = pm;
+	if (msk->pm.ops->init)
+		msk->pm.ops->init(msk);
+
+	pr_debug("pm %s initialized\n", pm->name);
+	return 0;
+}
+
+void mptcp_pm_release(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_ops *pm = msk->pm.ops;
+
+	if (!pm)
+		return;
+
+	msk->pm.ops = NULL;
+	if (pm->release)
+		pm->release(msk);
+
+	bpf_module_put(pm, pm->owner);
+}

net/mptcp/protocol.c

@@ -3307,6 +3307,7 @@ void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags)
 	mptcp_token_destroy(msk);
 	mptcp_pm_free_anno_list(msk);
 	mptcp_free_local_addr_list(msk);
+	mptcp_pm_release(msk);
 }
 
 static void mptcp_destroy(struct sock *sk)

net/mptcp/protocol.h

@@ -220,6 +220,7 @@ struct mptcp_pm_data {
 	struct mptcp_addr_info remote;
 	struct list_head anno_list;
 	struct list_head userspace_pm_local_addr_list;
+	struct mptcp_pm_ops *ops;
 
 	spinlock_t	lock;		/*protects the whole PM data */
 
@@ -1054,6 +1055,8 @@ struct mptcp_pm_ops *mptcp_pm_find(const char *name);
 int mptcp_pm_validate(struct mptcp_pm_ops *pm);
 int mptcp_pm_register(struct mptcp_pm_ops *pm);
 void mptcp_pm_unregister(struct mptcp_pm_ops *pm);
+int mptcp_pm_initialize(struct mptcp_sock *msk, struct mptcp_pm_ops *pm);
+void mptcp_pm_release(struct mptcp_sock *msk);
 
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);