Revert "core/txpool/legacypool: protect cache with mutex (#27898)"

This reverts commit 10133ba062.

core/txpool/legacypool/list.go

@@ -53,10 +53,9 @@ func (h *nonceHeap) Pop() interface{} {
 // sortedMap is a nonce->transaction hash map with a heap based index to allow
 // iterating over the contents in a nonce-incrementing way.
 type sortedMap struct {
-	items   map[uint64]*types.Transaction // Hash map storing the transaction data
-	index   *nonceHeap                    // Heap of nonces of all the stored transactions (non-strict mode)
-	cache   types.Transactions            // Cache of the transactions already sorted
-	cacheMu sync.Mutex                    // Mutex covering the cache
+	items map[uint64]*types.Transaction // Hash map storing the transaction data
+	index *nonceHeap                    // Heap of nonces of all the stored transactions (non-strict mode)
+	cache types.Transactions            // Cache of the transactions already sorted
 }
 
 // newSortedMap creates a new nonce-sorted transaction map.
@@ -79,9 +78,7 @@ func (m *sortedMap) Put(tx *types.Transaction) {
 	if m.items[nonce] == nil {
 		heap.Push(m.index, nonce)
 	}
-	m.cacheMu.Lock()
 	m.items[nonce], m.cache = tx, nil
-	m.cacheMu.Unlock()
 }
 
 // Forward removes all transactions from the map with a nonce lower than the
@@ -97,11 +94,9 @@ func (m *sortedMap) Forward(threshold uint64) types.Transactions {
 		delete(m.items, nonce)
 	}
 	// If we had a cached order, shift the front
-	m.cacheMu.Lock()
 	if m.cache != nil {
 		m.cache = m.cache[len(removed):]
 	}
-	m.cacheMu.Unlock()
 	return removed
 }
 
@@ -125,9 +120,7 @@ func (m *sortedMap) reheap() {
 		*m.index = append(*m.index, nonce)
 	}
 	heap.Init(m.index)
-	m.cacheMu.Lock()
 	m.cache = nil
-	m.cacheMu.Unlock()
 }
 
 // filter is identical to Filter, but **does not** regenerate the heap. This method
@@ -143,9 +136,7 @@ func (m *sortedMap) filter(filter func(*types.Transaction) bool) types.Transacti
 		}
 	}
 	if len(removed) > 0 {
-		m.cacheMu.Lock()
 		m.cache = nil
-		m.cacheMu.Unlock()
 	}
 	return removed
 }
@@ -169,11 +160,9 @@ func (m *sortedMap) Cap(threshold int) types.Transactions {
 	heap.Init(m.index)
 
 	// If we had a cache, shift the back
-	m.cacheMu.Lock()
 	if m.cache != nil {
 		m.cache = m.cache[:len(m.cache)-len(drops)]
 	}
-	m.cacheMu.Unlock()
 	return drops
 }
 
@@ -193,9 +182,7 @@ func (m *sortedMap) Remove(nonce uint64) bool {
 		}
 	}
 	delete(m.items, nonce)
-	m.cacheMu.Lock()
 	m.cache = nil
-	m.cacheMu.Unlock()
 
 	return true
 }
@@ -219,9 +206,7 @@ func (m *sortedMap) Ready(start uint64) types.Transactions {
 		delete(m.items, next)
 		heap.Pop(m.index)
 	}
-	m.cacheMu.Lock()
 	m.cache = nil
-	m.cacheMu.Unlock()
 
 	return ready
 }
@@ -232,8 +217,6 @@ func (m *sortedMap) Len() int {
 }
 
 func (m *sortedMap) flatten() types.Transactions {
-	m.cacheMu.Lock()
-	defer m.cacheMu.Unlock()
 	// If the sorting was not cached yet, create and cache it
 	if m.cache == nil {
 		m.cache = make(types.Transactions, 0, len(m.items))
@@ -249,8 +232,8 @@ func (m *sortedMap) flatten() types.Transactions {
 // sorted internal representation. The result of the sorting is cached in case
 // it's requested again before any modifications are made to the contents.
 func (m *sortedMap) Flatten() types.Transactions {
+	// Copy the cache to prevent accidental modifications
 	cache := m.flatten()
-	// Copy the cache to prevent accidental modification
 	txs := make(types.Transactions, len(cache))
 	copy(txs, cache)
 	return txs