From 6b66efb61a111c03a892150884ee87836d87ac2a Mon Sep 17 00:00:00 2001
From: JingZhang Chen <iRoiocam@gmail.com>
Date: Sat, 31 Aug 2024 04:29:02 +0800
Subject: [PATCH] apply suggestions

---
 .../io/lettuce/core/protocol/SharedLock.java     | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/src/main/java/io/lettuce/core/protocol/SharedLock.java b/src/main/java/io/lettuce/core/protocol/SharedLock.java
index f2e90186ee..c3ad425c16 100644
--- a/src/main/java/io/lettuce/core/protocol/SharedLock.java
+++ b/src/main/java/io/lettuce/core/protocol/SharedLock.java
@@ -26,7 +26,7 @@ class SharedLock {
 
     private final Lock lock = new ReentrantLock();
 
-    private final ThreadLocal<Integer> sharedCnt = ThreadLocal.withInitial(() -> 0);
+    private final ThreadLocal<Integer> threadWriters = ThreadLocal.withInitial(() -> 0);
 
     private volatile long writers = 0;
 
@@ -47,7 +47,7 @@ void incrementWriters() {
 
                 if (WRITERS.get(this) >= 0) {
                     WRITERS.incrementAndGet(this);
-                    sharedCnt.set(sharedCnt.get() + 1);
+                    threadWriters.set(threadWriters.get() + 1);
                     return;
                 }
             }
@@ -66,7 +66,7 @@ void decrementWriters() {
         }
 
         WRITERS.decrementAndGet(this);
-        sharedCnt.set(sharedCnt.get() - 1);
+        threadWriters.set(threadWriters.get() - 1);
     }
 
     /**
@@ -125,12 +125,8 @@ private void lockWritersExclusive() {
         try {
             for (;;) {
 
-                if (WRITERS.compareAndSet(this, 0, -1)) {
-                    exclusiveLockOwner = Thread.currentThread();
-                    return;
-                }
-                // reentrant exclusive lock
-                if (WRITERS.compareAndSet(this, sharedCnt.get(), -1)) {
+                // allow reentrant exclusive lock by comparing writers count and threadWriters count
+                if (WRITERS.compareAndSet(this, threadWriters.get(), -1)) {
                     exclusiveLockOwner = Thread.currentThread();
                     return;
                 }
@@ -147,7 +143,7 @@ private void unlockWritersExclusive() {
 
         if (exclusiveLockOwner == Thread.currentThread()) {
             // check exclusive look not reentrant first
-            if (WRITERS.compareAndSet(this, -1, sharedCnt.get())) {
+            if (WRITERS.compareAndSet(this, -1, threadWriters.get())) {
                 exclusiveLockOwner = null;
                 return;
             }