mptcp: add pm_nl_pernet helpers

This patch adds two pm_nl_pernet related helpers, named pm_nl_get_pernet()
and pm_nl_get_pernet_from_msk() to get pm_nl_pernet from 'net' or 'msk'.
Use these helpers instead of using net_generic() directly.

Suggested-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/pm_netlink.c

@@ -55,6 +55,17 @@ struct pm_nl_pernet {
 #define MPTCP_PM_ADDR_MAX	8
 #define ADD_ADDR_RETRANS_MAX	3
 
+static struct pm_nl_pernet *pm_nl_get_pernet(const struct net *net)
+{
+	return net_generic(net, pm_nl_pernet_id);
+}
+
+static struct pm_nl_pernet *
+pm_nl_get_pernet_from_msk(const struct mptcp_sock *msk)
+{
+	return pm_nl_get_pernet(sock_net((struct sock *)msk));
+}
+
 static bool addresses_equal(const struct mptcp_addr_info *a,
 			    const struct mptcp_addr_info *b, bool use_port)
 {
@@ -206,43 +217,39 @@ select_signal_address(struct pm_nl_pernet *pernet, const struct mptcp_sock *msk)
 
 unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk)
 {
-	const struct pm_nl_pernet *pernet;
+	const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	pernet = net_generic(sock_net((const struct sock *)msk), pm_nl_pernet_id);
 	return READ_ONCE(pernet->add_addr_signal_max);
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_signal_max);
 
 unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk)
 {
-	struct pm_nl_pernet *pernet;
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 	return READ_ONCE(pernet->add_addr_accept_max);
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_add_addr_accept_max);
 
 unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk)
 {
-	struct pm_nl_pernet *pernet;
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 	return READ_ONCE(pernet->subflows_max);
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_subflows_max);
 
 unsigned int mptcp_pm_get_local_addr_max(const struct mptcp_sock *msk)
 {
-	struct pm_nl_pernet *pernet;
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
-	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
 	return READ_ONCE(pernet->local_addr_max);
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_local_addr_max);
 
 bool mptcp_pm_nl_check_work_pending(struct mptcp_sock *msk)
 {
-	struct pm_nl_pernet *pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
 	if (msk->pm.subflows == mptcp_pm_get_subflows_max(msk) ||
 	    (find_next_and_bit(pernet->id_bitmap, msk->pm.id_avail_bitmap,
@@ -508,7 +515,7 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	struct pm_nl_pernet *pernet;
 	unsigned int subflows_max;
 
-	pernet = net_generic(sock_net(sk), pm_nl_pernet_id);
+	pernet = pm_nl_get_pernet(sock_net(sk));
 
 	add_addr_signal_max = mptcp_pm_get_add_addr_signal_max(msk);
 	local_addr_max = mptcp_pm_get_local_addr_max(msk);
@@ -604,7 +611,7 @@ static unsigned int fill_local_addresses_vec(struct mptcp_sock *msk,
 	unsigned int subflows_max;
 	int i = 0;
 
-	pernet = net_generic(sock_net(sk), pm_nl_pernet_id);
+	pernet = pm_nl_get_pernet_from_msk(msk);
 	subflows_max = mptcp_pm_get_subflows_max(msk);
 
 	rcu_read_lock();
@@ -1023,7 +1030,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	if (addresses_equal(&msk_local, &skc_local, false))
 		return 0;
 
-	pernet = net_generic(sock_net((struct sock *)msk), pm_nl_pernet_id);
+	pernet = pm_nl_get_pernet_from_msk(msk);
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
@@ -1214,7 +1221,7 @@ skip_family:
 
 static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
 {
-	return net_generic(genl_info_net(info), pm_nl_pernet_id);
+	return pm_nl_get_pernet(genl_info_net(info));
 }
 
 static int mptcp_nl_add_subflow_or_signal_addr(struct net *net)
@@ -1308,7 +1315,7 @@ int mptcp_pm_get_flags_and_ifindex_by_id(struct net *net, unsigned int id,
 
 	if (id) {
 		rcu_read_lock();
-		entry = __lookup_addr_by_id(net_generic(net, pm_nl_pernet_id), id);
+		entry = __lookup_addr_by_id(pm_nl_get_pernet(net), id);
 		if (entry) {
 			*flags = entry->flags;
 			*ifindex = entry->ifindex;
@@ -1655,7 +1662,7 @@ static int mptcp_nl_cmd_dump_addrs(struct sk_buff *msg,
 	void *hdr;
 	int i;
 
-	pernet = net_generic(net, pm_nl_pernet_id);
+	pernet = pm_nl_get_pernet(net);
 
 	spin_lock_bh(&pernet->lock);
 	for (i = id; i < MPTCP_PM_MAX_ADDR_ID + 1; i++) {
@@ -2167,7 +2174,7 @@ static struct genl_family mptcp_genl_family __ro_after_init = {
 
 static int __net_init pm_nl_init_net(struct net *net)
 {
-	struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
+	struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
 
 	INIT_LIST_HEAD_RCU(&pernet->local_addr_list);
 
@@ -2189,7 +2196,7 @@ static void __net_exit pm_nl_exit_net(struct list_head *net_list)
 	struct net *net;
 
 	list_for_each_entry(net, net_list, exit_list) {
-		struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
+		struct pm_nl_pernet *pernet = pm_nl_get_pernet(net);
 
 		/* net is removed from namespace list, can't race with
 		 * other modifiers, also netns core already waited for a