Instead of manually pausing and unpausing, automatically pause the

memory card thread when mounting the first drive, and automatically
unpause it when we unmount the last drive.  (We can do this simplification
because we always mount and unmount memory cards explicitly when
reading and writing to them.)

stepmania/src/MemoryCardManager.cpp

@@ -35,6 +35,7 @@ MemoryCardManager::MemoryCardManager()
 	FOREACH_PlayerNumber( p )
 	{
 		m_bTooLate[p] = false;
+		m_bMounted[p] = false;
 	}
 	
 	/* These can play at any time.  Preload them, so we don't cause a skip in gameplay. */
@@ -261,6 +262,8 @@ void MemoryCardManager::MountAllUsedCards()
 	}
 }
 
+/* Called in EndGame just after writing the profile.  Called by PlayersFinalized just after
+ * reading the profile.  Should never block; use FlushAndReset to block until writes complete. */
 void MemoryCardManager::UnmountAllUsedCards()
 {
 	FOREACH_EnabledPlayer( p )
@@ -279,8 +282,23 @@ void MemoryCardManager::MountCard( PlayerNumber pn )
 {
 	ASSERT( !m_Device[pn].IsBlank() );
 
+	/* Pause the mounting thread when we mount the first drive. */
+	bool bNeedPause = true;
+	FOREACH_PlayerNumber( p )
+		if( m_bMounted[p] )
+			bNeedPause = false;
+	if( bNeedPause )
+		this->PauseMountingThread();
+
 	if( !m_pDriver->MountAndTestWrite(&m_Device[pn]) )
+	{
+		if( bNeedPause )
+			this->UnPauseMountingThread();
+
 		return;
+	}
+
+	m_bMounted[p] = true;
 
 	/* If this is the first time we're mounting the device, mount the VFS drivers.
 	 * Simply mounting our VFS on a directory doesn't actually touch the directory,
@@ -305,8 +323,21 @@ void MemoryCardManager::UnmountCard( PlayerNumber pn )
 {
 	ASSERT( !m_Device[pn].IsBlank() );
 
+	if( !m_bMounted[pn] )
+		return;
+
 	/* Leave our own filesystem drivers mounted. */
 	m_pDriver->Unmount( &m_Device[pn] );
+
+	m_bMounted[pn] = false;
+
+	/* Unpause the mounting thread when we unmount the last drive. */
+	bool bNeedUnpause = true;
+	FOREACH_PlayerNumber( p )
+		if( m_bMounted[p] )
+			bNeedUnpause = false;
+	if( bNeedUnpause )
+		this->UnPauseMountingThread();
 }
 
 void MemoryCardManager::FlushAndReset()