From 1919181b87bea0b20336ab9d28f40ee72f099571 Mon Sep 17 00:00:00 2001
From: Pascal Fischer <pascal@netbird.io>
Date: Wed, 7 May 2025 17:15:58 +0200
Subject: [PATCH] exchange semaphore

---
 management/server/account.go |  4 ++--
 management/server/peer.go    | 40 +++++++++++++++++++++---------------
 2 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/management/server/account.go b/management/server/account.go
index 5c474a343..e11d1816c 100644
--- a/management/server/account.go
+++ b/management/server/account.go
@@ -1522,8 +1522,8 @@ func (am *DefaultAccountManager) SyncPeerMeta(ctx context.Context, peerPubKey st
 		return err
 	}
 
-	unlock := am.Store.AcquireReadLockByUID(ctx, accountID)
-	defer unlock()
+	// unlock := am.Store.AcquireReadLockByUID(ctx, accountID)
+	// defer unlock()
 
 	unlockPeer := am.Store.AcquireWriteLockByUID(ctx, peerPubKey)
 	defer unlockPeer()
diff --git a/management/server/peer.go b/management/server/peer.go
index 93259813b..9a790c3dd 100644
--- a/management/server/peer.go
+++ b/management/server/peer.go
@@ -10,7 +10,6 @@ import (
 	"slices"
 	"strings"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"github.com/rs/xid"
@@ -448,32 +447,41 @@ func (am *DefaultAccountManager) GetPeerNetwork(ctx context.Context, peerID stri
 }
 
 var (
-	semaphoreLimit int32 = 10
-	semaphores           = sync.Map{}
+	semaphoreLimit = 10
+	semaphores     = make(map[string]chan struct{})
+	mu             sync.Mutex
 )
 
 func TryAcquire(key string) error {
-	v, _ := semaphores.LoadOrStore(key, new(atomic.Int32))
-	counter := v.(*atomic.Int32)
+	mu.Lock()
+	ch, ok := semaphores[key]
+	if !ok {
+		ch = make(chan struct{}, semaphoreLimit)
+		semaphores[key] = ch
+	}
+	mu.Unlock()
 
-	for {
-		current := counter.Load()
-		if current >= semaphoreLimit {
-			return errors.New("keep your calm")
-		}
-		if counter.CompareAndSwap(current, current+1) {
-			return nil
-		}
+	select {
+	case ch <- struct{}{}:
+		return nil
+	default:
+		return errors.New("keep your calm")
 	}
 }
 
 func Release(key string) {
-	v, ok := semaphores.Load(key)
+	mu.Lock()
+	ch, ok := semaphores[key]
+	mu.Unlock()
 	if !ok {
 		return
 	}
-	counter := v.(*atomic.Int32)
-	counter.Add(-1)
+
+	select {
+	case <-ch:
+	default:
+		return
+	}
 }
 
 // AddPeer adds a new peer to the Store.