mptcp: drop free_list for deleting entries

mptcp_pm_remove_addrs() actually only deletes one address, which does
not match its name. This patch renames it to mptcp_pm_remove_addr_entry()
and changes the parameter "rm_list" to "entry".

With the help of mptcp_pm_remove_addr_entry(), it's no longer necessary to
move the entry to be deleted to free_list and then traverse the list to
delete the entry, which is not allowed in BPF. The entry can be directly
deleted through list_del_rcu() and sock_kfree_s() now.

Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20241213-net-next-mptcp-pm-misc-cleanup-v1-5-ddb6d00109a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Geliang Tang

net/mptcp/pm_userspace.c

@@ -287,41 +287,31 @@ static int mptcp_userspace_pm_remove_id_zero_address(struct mptcp_sock *msk,
 	return err;
 }
 
-void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list)
+void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
+				struct mptcp_pm_addr_entry *entry)
 {
 	struct mptcp_rm_list alist = { .nr = 0 };
-	struct mptcp_pm_addr_entry *entry;
 	int anno_nr = 0;
 
-	list_for_each_entry(entry, rm_list, list) {
-		if (alist.nr >= MPTCP_RM_IDS_MAX)
-			break;
-
-		/* only delete if either announced or matching a subflow */
-		if (mptcp_remove_anno_list_by_saddr(msk, &entry->addr))
-			anno_nr++;
-		else if (!mptcp_lookup_subflow_by_saddr(&msk->conn_list,
-							&entry->addr))
-			continue;
+	/* only delete if either announced or matching a subflow */
+	if (mptcp_remove_anno_list_by_saddr(msk, &entry->addr))
+		anno_nr++;
+	else if (!mptcp_lookup_subflow_by_saddr(&msk->conn_list, &entry->addr))
+		return;
 
-		alist.ids[alist.nr++] = entry->addr.id;
-	}
+	alist.ids[alist.nr++] = entry->addr.id;
 
-	if (alist.nr) {
-		spin_lock_bh(&msk->pm.lock);
-		msk->pm.add_addr_signaled -= anno_nr;
-		mptcp_pm_remove_addr(msk, &alist);
-		spin_unlock_bh(&msk->pm.lock);
-	}
+	spin_lock_bh(&msk->pm.lock);
+	msk->pm.add_addr_signaled -= anno_nr;
+	mptcp_pm_remove_addr(msk, &alist);
+	spin_unlock_bh(&msk->pm.lock);
 }
 
 int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct nlattr *id = info->attrs[MPTCP_PM_ATTR_LOC_ID];
 	struct mptcp_pm_addr_entry *match;
-	struct mptcp_pm_addr_entry *entry;
 	struct mptcp_sock *msk;
-	LIST_HEAD(free_list);
 	int err = -EINVAL;
 	struct sock *sk;
 	u8 id_val;
@@ -355,16 +345,14 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
-	list_move(&match->list, &free_list);
+	list_del_rcu(&match->list);
 	spin_unlock_bh(&msk->pm.lock);
 
-	mptcp_pm_remove_addrs(msk, &free_list);
+	mptcp_pm_remove_addr_entry(msk, match);
 
 	release_sock(sk);
 
-	list_for_each_entry_safe(match, entry, &free_list, list) {
-		sock_kfree_s(sk, match, sizeof(*match));
-	}
+	sock_kfree_s(sk, match, sizeof(*match));
 
 	err = 0;
 out:

net/mptcp/protocol.h

@@ -1038,7 +1038,8 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 			   const struct mptcp_addr_info *addr,
 			   bool echo);
 int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list);
-void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list);
+void mptcp_pm_remove_addr_entry(struct mptcp_sock *msk,
+				struct mptcp_pm_addr_entry *entry);
 
 void mptcp_free_local_addr_list(struct mptcp_sock *msk);