From 7bced1532b93ee7bd3757aca247249f67b953e33 Mon Sep 17 00:00:00 2001
From: Peter Rabbitson <ribasushi@protocol.ai>
Date: Tue, 6 Apr 2021 13:01:48 +0200
Subject: [PATCH] Convert the chainstore lock to RW

High read-API concurrency facilitates multiple calls to GetHeaviestTipSet
which in turn could slow down chainsync.
---
 chain/store/store.go | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/chain/store/store.go b/chain/store/store.go
index e0d71f0304b..7ebe31ec4bf 100644
--- a/chain/store/store.go
+++ b/chain/store/store.go
@@ -113,7 +113,7 @@ type ChainStore struct {
 
 	chainLocalBlockstore bstore.Blockstore
 
-	heaviestLk sync.Mutex
+	heaviestLk sync.RWMutex
 	heaviest   *types.TipSet
 
 	bestTips *pubsub.PubSub
@@ -775,10 +775,11 @@ func ReorgOps(lts func(types.TipSetKey) (*types.TipSet, error), a, b *types.TipS
 }
 
 // GetHeaviestTipSet returns the current heaviest tipset known (i.e. our head).
-func (cs *ChainStore) GetHeaviestTipSet() *types.TipSet {
-	cs.heaviestLk.Lock()
-	defer cs.heaviestLk.Unlock()
-	return cs.heaviest
+func (cs *ChainStore) GetHeaviestTipSet() (ts *types.TipSet) {
+	cs.heaviestLk.RLock()
+	ts = cs.heaviest
+	cs.heaviestLk.RUnlock()
+	return
 }
 
 func (cs *ChainStore) AddToTipSetTracker(b *types.BlockHeader) error {