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iokit/Kernel/IOSharedDataQueue.cpp xnu-3248.30.4 xnu-1228
--- xnu/xnu-3248.30.4/iokit/Kernel/IOSharedDataQueue.cpp
+++ xnu/xnu-1228/iokit/Kernel/IOSharedDataQueue.cpp
@@ -31,10 +31,6 @@
 #include <IOKit/IOLib.h>
 #include <IOKit/IOMemoryDescriptor.h>
 
-#ifdef enqueue
-#undef enqueue
-#endif
-
 #ifdef dequeue
 #undef dequeue
 #endif
@@ -74,51 +70,23 @@
 Boolean IOSharedDataQueue::initWithCapacity(UInt32 size)
 {
     IODataQueueAppendix *   appendix;
-    vm_size_t               allocSize;
-
+    
     if (!super::init()) {
         return false;
     }
-
-    _reserved = (ExpansionData *)IOMalloc(sizeof(struct ExpansionData));
-    if (!_reserved) {
-        return false;
-    }
-
-    if (size > UINT32_MAX - DATA_QUEUE_MEMORY_HEADER_SIZE - DATA_QUEUE_MEMORY_APPENDIX_SIZE) {
-        return false;
-    }
-    
-    allocSize = round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE);
-
-    if (allocSize < size) {
-        return false;
-    }
-
-    dataQueue = (IODataQueueMemory *)IOMallocAligned(allocSize, PAGE_SIZE);
+    
+    dataQueue = (IODataQueueMemory *)IOMallocAligned(round_page_32(size + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE), PAGE_SIZE);
     if (dataQueue == 0) {
         return false;
     }
-    bzero(dataQueue, allocSize);
 
     dataQueue->queueSize    = size;
-//  dataQueue->head         = 0;
-//  dataQueue->tail         = 0;
-
-    if (!setQueueSize(size)) {
-        return false;
-    }
+    dataQueue->head         = 0;
+    dataQueue->tail         = 0;
     
     appendix            = (IODataQueueAppendix *)((UInt8 *)dataQueue + size + DATA_QUEUE_MEMORY_HEADER_SIZE);
     appendix->version   = 0;
-
-    if (!notifyMsg) {
-        notifyMsg = IOMalloc(sizeof(mach_msg_header_t));
-        if (!notifyMsg)
-            return false;
-    }
-    bzero(notifyMsg, sizeof(mach_msg_header_t));
-
+    notifyMsg           = &(appendix->msgh);
     setNotificationPort(MACH_PORT_NULL);
 
     return true;
@@ -127,19 +95,10 @@
 void IOSharedDataQueue::free()
 {
     if (dataQueue) {
-        IOFreeAligned(dataQueue, round_page(getQueueSize() + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE));
+        IOFreeAligned(dataQueue, round_page_32(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE));
         dataQueue = NULL;
-        if (notifyMsg) {
-            IOFree(notifyMsg, sizeof(mach_msg_header_t));
-            notifyMsg = NULL;
-        }
-    }
-
-    if (_reserved) {
-        IOFree (_reserved, sizeof(struct ExpansionData));
-        _reserved = NULL;
-    } 
-    
+    }
+
     super::free();
 }
 
@@ -148,7 +107,7 @@
     IOMemoryDescriptor *descriptor = 0;
 
     if (dataQueue != 0) {
-        descriptor = IOMemoryDescriptor::withAddress(dataQueue, getQueueSize() + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE, kIODirectionOutIn);
+        descriptor = IOMemoryDescriptor::withAddress(dataQueue, dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE, kIODirectionOutIn);
     }
 
     return descriptor;
@@ -160,29 +119,22 @@
     IODataQueueEntry *entry = 0;
 
     if (dataQueue && (dataQueue->head != dataQueue->tail)) {
-        IODataQueueEntry *  head        = 0;
+        IODataQueueEntry *  head		= 0;
         UInt32              headSize    = 0;
         UInt32              headOffset  = dataQueue->head;
-        UInt32              queueSize   = getQueueSize();
+        UInt32              queueSize   = dataQueue->queueSize;
+
+        head 		= (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
+        headSize 	= head->size;
         
-        if (headOffset >= queueSize) {
-            return NULL;
-        }
-        
-        head         = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
-        headSize     = head->size;
-        
-        // Check if there's enough room before the end of the queue for a header.
+		// Check if there's enough room before the end of the queue for a header.
         // If there is room, check if there's enough room to hold the header and
         // the data.
-        
-        if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
-            (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
-            (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
-            (headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
+
+        if ((headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
+            ((headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE) > queueSize))
+        {
             // No room for the header or the data, wrap to the beginning of the queue.
-            // Note: wrapping even with the UINT32_MAX checks, as we have to support
-            // queueSize of UINT32_MAX
             entry = dataQueue->queue;
         } else {
             entry = head;
@@ -190,93 +142,6 @@
     }
 
     return entry;
-}
-
-Boolean IOSharedDataQueue::enqueue(void * data, UInt32 dataSize)
-{
-    const UInt32       head      = dataQueue->head;  // volatile
-    const UInt32       tail      = dataQueue->tail;
-    const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
-    IODataQueueEntry * entry;
-    
-    // Check for overflow of entrySize
-    if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
-        return false;
-    }
-    // Check for underflow of (getQueueSize() - tail)
-    if (getQueueSize() < tail || getQueueSize() < head) {
-        return false;
-    }
-    
-    if ( tail >= head )
-    {
-        // Is there enough room at the end for the entry?
-        if ((entrySize <= UINT32_MAX - tail) &&
-            ((tail + entrySize) <= getQueueSize()) )
-        {
-            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.
-            
-            OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
-        }
-        else if ( head > entrySize )     // Is there enough room at the beginning?
-        {
-            // 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 ( ( getQueueSize() - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
-            {
-                ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
-            }
-            
-            memcpy(&dataQueue->queue->data, data, dataSize);
-            OSCompareAndSwap(dataQueue->tail, entrySize, &dataQueue->tail);
-        }
-        else
-        {
-            return false;    // queue is full
-        }
-    }
-    else
-    {
-        // Do not allow the tail to catch up to the head when the queue is full.
-        // That's why the comparison uses a '>' rather than '>='.
-        
-        if ( (head - tail) > entrySize )
-        {
-            entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
-            
-            entry->size = dataSize;
-            memcpy(&entry->data, data, dataSize);
-            OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
-        }
-        else
-        {
-            return false;    // queue is full
-        }
-    }
-    
-    // Send notification (via mach message) that data is available.
-    
-    if ( ( head == tail )                                                   /* queue was empty prior to enqueue() */
-        ||   ( dataQueue->head == tail ) )   /* queue was emptied during enqueue() */
-    {
-        sendDataAvailableNotification();
-    }
-    
-    return true;
 }
 
 Boolean IOSharedDataQueue::dequeue(void *data, UInt32 *dataSize)
@@ -288,53 +153,36 @@
 
     if (dataQueue) {
         if (dataQueue->head != dataQueue->tail) {
-            IODataQueueEntry *  head        = 0;
+            IODataQueueEntry *  head		= 0;
             UInt32              headSize    = 0;
             UInt32              headOffset  = dataQueue->head;
-            UInt32              queueSize   = getQueueSize();
+            UInt32              queueSize   = dataQueue->queueSize;
+
+            head 		= (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
+            headSize 	= head->size;
             
-            if (headOffset > queueSize) {
-                return false;
-            }
-            
-            head         = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
-            headSize     = head->size;
-            
-            // we wrapped around to beginning, so read from there
-            // either there was not even room for the header
-            if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
-                (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
-                // or there was room for the header, but not for the data
-                (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
-                (headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
-                // Note: we have to wrap to the beginning even with the UINT32_MAX checks
-                // because we have to support a queueSize of UINT32_MAX.
+            // we wraped around to beginning, so read from there
+			// either there was not even room for the header
+			if ((headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
+				// or there was room for the header, but not for the data
+				((headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE) > queueSize)) {
                 entry           = dataQueue->queue;
                 entrySize       = entry->size;
-                if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
-                    (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
-                    return false;
-                }
                 newHeadOffset   = entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
-                // else it is at the end
+            // else it is at the end
             } else {
                 entry           = head;
                 entrySize       = entry->size;
-                if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
-                    (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headOffset) ||
-                    (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE + headOffset > queueSize)) {
-                    return false;
-                }
                 newHeadOffset   = headOffset + entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
             }
         }
-        
+
         if (entry) {
             if (data) {
                 if (dataSize) {
                     if (entrySize <= *dataSize) {
                         memcpy(data, &(entry->data), entrySize);
-                        OSCompareAndSwap( dataQueue->head, newHeadOffset, (SInt32 *)&dataQueue->head);
+                        dataQueue->head = newHeadOffset;
                     } else {
                         retVal = FALSE;
                     }
@@ -342,7 +190,7 @@
                     retVal = FALSE;
                 }
             } else {
-                OSCompareAndSwap( dataQueue->head, newHeadOffset, (SInt32 *)&dataQueue->head);
+                dataQueue->head = newHeadOffset;
             }
 
             if (dataSize) {
@@ -358,22 +206,6 @@
     return retVal;
 }
 
-UInt32 IOSharedDataQueue::getQueueSize()
-{
-    if (!_reserved) {
-        return 0;
-    }
-    return _reserved->queueSize;
-}
-
-Boolean IOSharedDataQueue::setQueueSize(UInt32 size)
-{
-    if (!_reserved) {
-        return false;
-    }
-    _reserved->queueSize = size;
-    return true;
-}
 
 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 0);
 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 1);