--- xnu/xnu-792.12.6/iokit/Kernel/IODataQueue.cpp
+++ xnu/xnu-201.5/iokit/Kernel/IODataQueue.cpp
@@ -1,31 +1,23 @@
 /*
  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
+ * @APPLE_LICENSE_HEADER_START@
  * 
- * This file contains Original Code and/or Modifications of Original Code 
- * as defined in and that are subject to the Apple Public Source License 
- * Version 2.0 (the 'License'). You may not use this file except in 
- * compliance with the License.  The rights granted to you under the 
- * License may not be used to create, or enable the creation or 
- * redistribution of, unlawful or unlicensed copies of an Apple operating 
- * system, or to circumvent, violate, or enable the circumvention or 
- * violation of, any terms of an Apple operating system software license 
- * agreement.
- *
- * Please obtain a copy of the License at 
- * http://www.opensource.apple.com/apsl/ and read it before using this 
- * file.
- *
- * The Original Code and all software distributed under the License are 
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
- * Please see the License for the specific language governing rights and 
- * limitations under the License.
- *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
  */
 
 #include <IOKit/IODataQueue.h>
@@ -79,7 +71,7 @@
         return false;
     }
 
-    dataQueue = (IODataQueueMemory *)IOMallocAligned(round_page_32(size + DATA_QUEUE_MEMORY_HEADER_SIZE), PAGE_SIZE);
+    dataQueue = (IODataQueueMemory *)IOMallocAligned(round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE), PAGE_SIZE);
     if (dataQueue == 0) {
         return false;
     }
@@ -99,7 +91,7 @@
 void IODataQueue::free()
 {
     if (dataQueue) {
-        IOFreeAligned(dataQueue, round_page_32(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
+        IOFreeAligned(dataQueue, round_page(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
     }
 
     super::free();
@@ -113,39 +105,24 @@
     const UInt32       tail      = dataQueue->tail;
     const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
     IODataQueueEntry * entry;
-
+    
     if ( tail >= head )
     {
-        // Is there enough room at the end for the entry?
-        if ( (tail + entrySize) <= dataQueue->queueSize )
+        if ( (tail + entrySize) < dataQueue->queueSize )
         {
             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 
             entry->size = dataSize;
             memcpy(&entry->data, data, dataSize);
-
-            // The tail can be out of bound when the size of the new entry
-            // exactly matches the available space at the end of the queue.
-            // The tail can range from 0 to dataQueue->queueSize inclusive.
-
             dataQueue->tail += entrySize;
         }
-        else if ( head > entrySize ) 	// Is there enough room at the beginning?
+        else if ( head > entrySize )
         {
             // Wrap around to the beginning, but do not allow the tail to catch
             // up to the head.
 
             dataQueue->queue->size = dataSize;
-
-            // We need to make sure that there is enough room to set the size before
-            // doing this. The user client checks for this and will look for the size
-            // at the beginning if there isn't room for it at the end.
-
-            if ( ( dataQueue->queueSize - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
-            {
-                ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
-            }
-
+            ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
             memcpy(&dataQueue->queue->data, data, dataSize);
             dataQueue->tail = entrySize;
         }