--- xnu/xnu-2050.22.13/iokit/Kernel/IOBufferMemoryDescriptor.cpp
+++ xnu/xnu-2422.1.72/iokit/Kernel/IOBufferMemoryDescriptor.cpp
@@ -71,208 +71,26 @@
 
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-#if 0
-#undef assert
-#define assert(ex)  \
-	((ex) ? (void)0 : Assert(__FILE__, __LINE__, # ex))
-#endif
-
-enum
-{
-    kIOPageAllocChunkBytes = (PAGE_SIZE / 64),
-    kIOPageAllocSignature  = 'iopa'
-};
-
-struct io_pagealloc_t
-{
-    queue_chain_t link;
-    uint64_t      avail;
-    uint32_t      signature;
-};
-typedef struct io_pagealloc_t io_pagealloc_t;
-
-typedef char io_pagealloc_t_assert[(sizeof(io_pagealloc_t) <= kIOPageAllocChunkBytes) ? 1 : -1];
-
-IOSimpleLock * gIOPageAllocLock;
-queue_head_t   gIOPageAllocList;
-vm_size_t      gIOPageAllocCount;
-vm_size_t      gIOPageAllocBytes;
-
-static io_pagealloc_t * 
-iopa_allocpage(void)
-{
-    kern_return_t    kr;
-    io_pagealloc_t * pa;
-    vm_address_t     vmaddr = 0;
-
-    int options = 0; // KMA_LOMEM;
-    kr = kernel_memory_allocate(kernel_map, &vmaddr,
-				page_size, 0, options);
-    if (KERN_SUCCESS != kr) return (0);
-
-    bzero((void *) vmaddr, page_size);
-    pa = (typeof(pa)) (vmaddr + page_size - kIOPageAllocChunkBytes);
-
-    pa->signature = kIOPageAllocSignature;
-    pa->avail     = -2ULL;
-
-    return (pa);
-}
-
-static void 
-iopa_freepage(io_pagealloc_t * pa)
-{
-    kmem_free( kernel_map, trunc_page((uintptr_t) pa), page_size);
-}
-
-static uintptr_t
-iopa_allocinpage(io_pagealloc_t * pa, uint32_t count, uint64_t align)
-{
-    uint32_t n, s;
-    uint64_t avail = pa->avail;
-
-    assert(avail);
-
-    // find strings of count 1 bits in avail
-    for (n = count; n > 1; n -= s)
-    {
-    	s = n >> 1;
-    	avail = avail & (avail << s);
-    }
-    // and aligned
-    avail &= align;
-
-    if (avail)
-    {
-	n = __builtin_clzll(avail);
-	pa->avail &= ~((-1ULL << (64 - count)) >> n);
-	if (!pa->avail && pa->link.next)
-	{
-	    remque(&pa->link);
-	    pa->link.next = 0;
-	}
-	return (n * kIOPageAllocChunkBytes + trunc_page((uintptr_t) pa));
-    }
-
-    return (0);
-}
-
-static uint32_t 
-log2up(uint32_t size)
-{
-    if (size <= 1) size = 0;
-    else size = 32 - __builtin_clz(size - 1);
-    return (size);
-}
-
-static uintptr_t 
-iopa_alloc(vm_size_t bytes, uint32_t balign)
-{
-    static const uint64_t align_masks[] = {
-	0xFFFFFFFFFFFFFFFF,
-	0xAAAAAAAAAAAAAAAA,
-	0x8888888888888888,
-	0x8080808080808080,
-	0x8000800080008000,
-	0x8000000080000000,
-	0x8000000000000000,
-    };
-    io_pagealloc_t * pa;
-    uintptr_t        addr = 0;
-    uint32_t         count;
-    uint64_t         align;
-
-    if (!bytes) bytes = 1;
-    count = (bytes + kIOPageAllocChunkBytes - 1) / kIOPageAllocChunkBytes;
-    align = align_masks[log2up((balign + kIOPageAllocChunkBytes - 1) / kIOPageAllocChunkBytes)];
-
-    IOSimpleLockLock(gIOPageAllocLock);
-    pa = (typeof(pa)) queue_first(&gIOPageAllocList);
-    while (!queue_end(&gIOPageAllocList, &pa->link))
-    {
-	addr = iopa_allocinpage(pa, count, align);
-	if (addr)
-	{
-	    gIOPageAllocBytes += bytes;
-	    break;
-	}
-	pa = (typeof(pa)) queue_next(&pa->link);
-    }
-    IOSimpleLockUnlock(gIOPageAllocLock);
-    if (!addr)
-    {
-        pa = iopa_allocpage();
-	if (pa)
-	{
-	    addr = iopa_allocinpage(pa, count, align);
-	    IOSimpleLockLock(gIOPageAllocLock);
-	    if (pa->avail) enqueue_head(&gIOPageAllocList, &pa->link);
-	    gIOPageAllocCount++;
-	    if (addr) gIOPageAllocBytes += bytes;
-	    IOSimpleLockUnlock(gIOPageAllocLock);
-	}
-    }
-
-    if (addr)
-    {
-        assert((addr & ((1 << log2up(balign)) - 1)) == 0);
-    	IOStatisticsAlloc(kIOStatisticsMallocAligned, bytes);
-#if IOALLOCDEBUG
-	debug_iomalloc_size += bytes;
-#endif
-    }
-
-    return (addr);
-}
-
-static void 
-iopa_free(uintptr_t addr, vm_size_t bytes)
-{
-    io_pagealloc_t * pa;
-    uint32_t         count;
-    uintptr_t        chunk;
-
-    if (!bytes) bytes = 1;
-
-    chunk = (addr & page_mask);
-    assert(0 == (chunk & (kIOPageAllocChunkBytes - 1)));
-
-    pa = (typeof(pa)) (addr | (page_size - kIOPageAllocChunkBytes));
-    assert(kIOPageAllocSignature == pa->signature);
-
-    count = (bytes + kIOPageAllocChunkBytes - 1) / kIOPageAllocChunkBytes;
-    chunk /= kIOPageAllocChunkBytes;
-
-    IOSimpleLockLock(gIOPageAllocLock);
-    if (!pa->avail)
-    {
-	assert(!pa->link.next);
-	enqueue_tail(&gIOPageAllocList, &pa->link);
-    }
-    pa->avail |= ((-1ULL << (64 - count)) >> chunk);
-    if (pa->avail != -2ULL) pa = 0;
-    else
-    {
-        remque(&pa->link);
-        pa->link.next = 0;
-        pa->signature = 0;
-	gIOPageAllocCount--;
-    }
-    gIOPageAllocBytes -= bytes;
-    IOSimpleLockUnlock(gIOPageAllocLock);
-    if (pa) iopa_freepage(pa);
-
-#if IOALLOCDEBUG
-    debug_iomalloc_size -= bytes;
-#endif
-    IOStatisticsAlloc(kIOStatisticsFreeAligned, bytes);
-}
-
-/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
-
 #define super IOGeneralMemoryDescriptor
 OSDefineMetaClassAndStructors(IOBufferMemoryDescriptor,
 				IOGeneralMemoryDescriptor);
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+static uintptr_t IOBMDPageProc(iopa_t * a)
+{
+    kern_return_t kr;
+    vm_address_t  vmaddr  = 0;
+    int           options = 0; // KMA_LOMEM;
+
+    kr = kernel_memory_allocate(kernel_map, &vmaddr,
+				page_size, 0, options);
+
+    if (KERN_SUCCESS != kr) vmaddr = 0;
+    else 		    bzero((void *) vmaddr, page_size);
+
+    return ((uintptr_t) vmaddr);
+}
 
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
@@ -449,7 +267,14 @@
 	{
             _internalFlags |= kInternalFlagPageAllocated;
             needZero        = false;
-            _buffer         = (void *) iopa_alloc(capacity, alignment);
+            _buffer         = (void *) iopa_alloc(&gIOBMDPageAllocator, &IOBMDPageProc, capacity, alignment);
+	    if (_buffer)
+	    {
+		IOStatisticsAlloc(kIOStatisticsMallocAligned, capacity);
+#if IOALLOCDEBUG
+		debug_iomalloc_size += capacity;
+#endif
+	    }
 	}
 	else if (alignment > 1)
 	{
@@ -500,7 +325,8 @@
 
 	    while (startAddr < endAddr)
 	    {
-		*startAddr;
+		UInt8 dummyVar = *startAddr;
+		(void) dummyVar;
 		startAddr += page_size;
  	    }
 	}
@@ -731,7 +557,16 @@
 	}
 	else if (kInternalFlagPageAllocated & internalFlags)
 	{
-            iopa_free((uintptr_t) buffer, size);
+	    uintptr_t page;
+            page = iopa_free(&gIOBMDPageAllocator, (uintptr_t) buffer, size);
+	    if (page)
+	    {
+		kmem_free(kernel_map, page, page_size);
+	    }
+#if IOALLOCDEBUG
+	    debug_iomalloc_size -= size;
+#endif
+	    IOStatisticsAlloc(kIOStatisticsFreeAligned, size);
 	}
         else if (alignment > 1)
 	{