From e2277feaba2d0e354d6d9e4e737b2feb45b0106d Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Sun, 11 Aug 2013 11:10:14 +0800
Subject: [PATCH] Kernel - Planning SMP fix with sleep edge case

---
 KernelLand/Kernel/semaphore.c |  9 +++++++--
 KernelLand/Kernel/threads.c   | 33 +++++++++++++++++++++++++++++++++
 KernelLand/Kernel/workqueue.c |  6 ++++++
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/KernelLand/Kernel/semaphore.c b/KernelLand/Kernel/semaphore.c
index 1111967a..e8175741 100644
--- a/KernelLand/Kernel/semaphore.c
+++ b/KernelLand/Kernel/semaphore.c
@@ -50,6 +50,11 @@ int Semaphore_Wait(tSemaphore *Sem, int MaxToTake)
 	}
 	else
 	{
+		#if 0
+		Threads_int_Sleep(THREAD_STAT_SEMAPHORESLEEP,
+			Sem, MaxToTake,
+			&Sem->Waiting, &Sem->LastWaiting, &Sem->Protector);
+		#endif
 		SHORTLOCK( &glThreadListLock );
 		
 		// - Remove from active list
@@ -75,9 +80,9 @@ int Semaphore_Wait(tSemaphore *Sem, int MaxToTake)
 			us, us->TID, us->ThreadName,
 			Sem, Sem->ModName, Sem->Name);
 		#endif
-		
-		SHORTREL( &Sem->Protector );	// Release first to make sure it is released
+		SHORTREL( &Sem->Protector );
 		SHORTREL( &glThreadListLock );
+		// NOTE: This can break in SMP
 		// Sleep until woken (either by getting what we need, or a timer event)
 		Threads_int_WaitForStatusEnd( THREAD_STAT_SEMAPHORESLEEP );
 		// We're only woken when there's something avaliable (or a signal arrives)
diff --git a/KernelLand/Kernel/threads.c b/KernelLand/Kernel/threads.c
index 67a2f637..9f760703 100644
--- a/KernelLand/Kernel/threads.c
+++ b/KernelLand/Kernel/threads.c
@@ -732,6 +732,39 @@ void Threads_int_WaitForStatusEnd(enum eThreadStatus Status)
 	}
 }
 
+void Threads_int_Sleep(enum eThreadStatus Status, void *Ptr, int Num, tThread **ListHead, tThread **ListTail, tShortSpinlock *Lock)
+{
+	SHORTLOCK( &glThreadListLock );
+	tThread	*us = Threads_RemActive();
+	us->Next = NULL;
+	// - Mark as sleeping
+	us->Status = Status;
+	us->WaitPointer = Ptr;
+	us->RetStatus = Num;	// Use RetStatus as a temp variable
+		
+	// - Add to waiting
+	if( ListTail ) {
+		if(*ListTail) {
+			(*ListTail)->Next = us;
+			*ListTail = us;
+		}
+		else {
+			*ListHead = us;
+			*ListTail = us;
+		}
+	}
+	else {
+		*ListHead = us;
+	}
+	
+	//if( Proc_ThreadSync(us) )
+	//	return ;
+	SHORTREL( &glThreadListLock );
+	if( Lock )
+		SHORTLOCK( Lock );
+	Threads_int_WaitForStatusEnd(Status);
+}
+
 /**
  * \fn void Threads_Sleep(void)
  * \brief Take the current process off the run queue
diff --git a/KernelLand/Kernel/workqueue.c b/KernelLand/Kernel/workqueue.c
index 2cd6a258..2083bde7 100644
--- a/KernelLand/Kernel/workqueue.c
+++ b/KernelLand/Kernel/workqueue.c
@@ -36,12 +36,18 @@ void *Workqueue_GetWork(tWorkqueue *Queue)
 			return ret;
 		}
 		
+		#if 0
+		Threads_int_Sleep(THREAD_STAT_QUEUESLEEP,
+			Queue, 0,
+			&Queue->Sleeper, NULL, &Queue->Protector);
+		#endif
 		// Go to sleep
 		SHORTLOCK(&glThreadListLock);
 		us = Threads_RemActive();
 		us->WaitPointer = Queue;
 		us->Status = THREAD_STAT_QUEUESLEEP;
 		Queue->Sleeper = us;
+		
 		SHORTREL(&Queue->Protector);	
 		SHORTREL(&glThreadListLock);
 		
-- 
2.20.1