txorphanage: Add lock annotations

EraseOrphansFor was called both with and without g_cs_orphans held,
correct that so that it's always called with it already held.

LimitOrphanTxSize was always called with g_cs_orphans held, so
add annotations and don't lock it a second time.

src/net_processing.cpp

@@ -1003,7 +1003,7 @@ void PeerManagerImpl::FinalizeNode(const CNode& node, bool& fUpdateConnectionTim
     for (const QueuedBlock& entry : state->vBlocksInFlight) {
         mapBlocksInFlight.erase(entry.hash);
     }
-    EraseOrphansFor(nodeid);
+    WITH_LOCK(g_cs_orphans, EraseOrphansFor(nodeid));
     m_txrequest.DisconnectedPeer(nodeid);
     nPreferredDownload -= state->fPreferredDownload;
     nPeersWithValidatedDownloads -= (state->nBlocksInFlightValidHeaders != 0);

src/txorphanage.cpp

@@ -55,7 +55,8 @@ int EraseOrphanTx(const uint256& txid)
 
 void EraseOrphansFor(NodeId peer)
 {
-    LOCK(g_cs_orphans);
+    AssertLockHeld(g_cs_orphans);
+
     int nErased = 0;
     std::map<uint256, COrphanTx>::iterator iter = mapOrphanTransactions.begin();
     while (iter != mapOrphanTransactions.end())
@@ -71,7 +72,7 @@ void EraseOrphansFor(NodeId peer)
 
 unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans)
 {
-    LOCK(g_cs_orphans);
+    AssertLockHeld(g_cs_orphans);
 
     unsigned int nEvicted = 0;
     static int64_t nNextSweep;

src/txorphanage.h

@@ -24,8 +24,8 @@ struct COrphanTx {
 };
 
 int EraseOrphanTx(const uint256& txid) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
-void EraseOrphansFor(NodeId peer);
-unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans);
+void EraseOrphansFor(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
+unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
 
 /** Map from txid to orphan transaction record. Limited by
  *  -maxorphantx/DEFAULT_MAX_ORPHAN_TRANSACTIONS */