banman: add thread annotations and mark members const where possible

Also remove misleading comment. ClearBanned is used by rpc as well.

src/banman.h

@@ -41,7 +41,7 @@ class BanMan
  BanMan(fs::path ban_file, CClientUIInterface* client_interface, int64_t default_ban_time);
  void Ban(const CNetAddr& netAddr, const BanReason& banReason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
  void Ban(const CSubNet& subNet, const BanReason& banReason, int64_t bantimeoffset = 0, bool sinceUnixEpoch = false);
- void ClearBanned(); // needed for unit testing
+ void ClearBanned();
  bool IsBanned(CNetAddr netAddr);
  bool IsBanned(CSubNet subNet);
  bool Unban(const CNetAddr& netAddr);
@@ -57,12 +57,12 @@ class BanMan
  //!clean unused entries (if bantime has expired)
  void SweepBanned();
 
- banmap_t m_banned;
  CCriticalSection m_cs_banned;
- bool m_is_dirty;
+ banmap_t m_banned GUARDED_BY(m_cs_banned);
+ bool m_is_dirty GUARDED_BY(m_cs_banned);
  CClientUIInterface* m_client_interface = nullptr;
  CBanDB m_ban_db;
- int64_t m_default_ban_time;
+ const int64_t m_default_ban_time;
 };
 
 extern std::unique_ptr<BanMan> g_banman;