From 71279b24ddba72562faab3304ba0797412467098 Mon Sep 17 00:00:00 2001
From: Rene Gollent <anevilyak@gmail.com>
Date: Thu, 4 Dec 2008 03:28:19 +0000
Subject: [PATCH] Adjust the thread counting to use atomic adds. This should
 prevent the previous scenario where many more threads than the limit could
 actually be spawned.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28775 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../registrar/mime/RegistrarThreadManager.cpp       | 13 ++++++++-----
 src/servers/registrar/mime/RegistrarThreadManager.h |  4 ++--
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/servers/registrar/mime/RegistrarThreadManager.cpp b/src/servers/registrar/mime/RegistrarThreadManager.cpp
index 187aaac0f5..a8cff5a201 100644
--- a/src/servers/registrar/mime/RegistrarThreadManager.cpp
+++ b/src/servers/registrar/mime/RegistrarThreadManager.cpp
@@ -87,19 +87,22 @@ status_t
 RegistrarThreadManager::LaunchThread(RegistrarThread *thread)
 {
 	status_t err = thread ? B_OK : B_BAD_VALUE;
-	if (!err)
-		err = fThreadCount < kThreadLimit ? (status_t)B_OK : (status_t)B_NO_MORE_THREADS;
+	if (!err) {
+		if (atomic_add(&fThreadCount, 1) >= kThreadLimit) {
+			err = B_NO_MORE_THREADS;
+			atomic_add(&fThreadCount, -1);
+		}
+	}
 
 	if (!err) {
 		fThreads.push_back(thread);
-		fThreadCount++;
 		err = thread->Run();
 		if (err) {
 			std::list<RegistrarThread*>::iterator i;
 			for (i = fThreads.begin(); i != fThreads.end();) {
 				if ((*i) == thread) {
 					i = fThreads.erase(i);
-					fThreadCount--;
+					atomic_add(&fThreadCount, -1);
 					break;
 				} else
 					++i;
@@ -234,7 +237,7 @@ std::list<RegistrarThread*>::iterator&
 RegistrarThreadManager::RemoveThread(std::list<RegistrarThread*>::iterator &i)
 {
 	delete *i;
-	fThreadCount--;
+	atomic_add(&fThreadCount, -1);
 	return (i = fThreads.erase(i));
 }
 
diff --git a/src/servers/registrar/mime/RegistrarThreadManager.h b/src/servers/registrar/mime/RegistrarThreadManager.h
index 12382a77e5..e111bcde54 100644
--- a/src/servers/registrar/mime/RegistrarThreadManager.h
+++ b/src/servers/registrar/mime/RegistrarThreadManager.h
@@ -33,13 +33,13 @@ public:
 	
 	uint ThreadCount() const;
 	
-	static const uint kThreadLimit = 12;
+	static const int kThreadLimit = 12;
 private:
 
 	std::list<RegistrarThread*>::iterator& RemoveThread(std::list<RegistrarThread*>::iterator &i);
 	
 	std::list<RegistrarThread*> fThreads;
-	uint fThreadCount;
+	vint32 fThreadCount;
 };
 
 #endif	// THREAD_MANAGER_H