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reactos/ntoskrnl/mm/ARM3/expool.c
Amine Khaldi c424146e2c Create a branch for cmake bringup. 
svn path=/branches/cmake-bringup/; revision=48236
2010-07-24 18:52:44 +00:00

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/*
* PROJECT: ReactOS Kernel
* LICENSE: BSD - See COPYING.ARM in the top level directory
* FILE: ntoskrnl/mm/ARM3/expool.c
* PURPOSE: ARM Memory Manager Executive Pool Manager
* PROGRAMMERS: ReactOS Portable Systems Group
*/
/* INCLUDES *******************************************************************/
#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>
#line 15 "ARM³::EXPOOL"
#define MODULE_INVOLVED_IN_ARM3
#include "../ARM3/miarm.h"
#undef ExAllocatePoolWithQuota
#undef ExAllocatePoolWithQuotaTag
BOOLEAN AllowPagedPool = TRUE;
/* GLOBALS ********************************************************************/
ULONG ExpNumberOfPagedPools;
POOL_DESCRIPTOR NonPagedPoolDescriptor;
PPOOL_DESCRIPTOR ExpPagedPoolDescriptor[16 + 1];
PPOOL_DESCRIPTOR PoolVector[2];
PVOID PoolTrackTable;
PKGUARDED_MUTEX ExpPagedPoolMutex;
/* Pool block/header/list access macros */
#define POOL_ENTRY(x) (PPOOL_HEADER)((ULONG_PTR)(x) - sizeof(POOL_HEADER))
#define POOL_FREE_BLOCK(x) (PLIST_ENTRY)((ULONG_PTR)(x) + sizeof(POOL_HEADER))
#define POOL_BLOCK(x, i) (PPOOL_HEADER)((ULONG_PTR)(x) + ((i) * POOL_BLOCK_SIZE))
#define POOL_NEXT_BLOCK(x) POOL_BLOCK((x), (x)->BlockSize)
#define POOL_PREV_BLOCK(x) POOL_BLOCK((x), -((x)->PreviousSize))
/*
* Pool list access debug macros, similar to Arthur's pfnlist.c work.
* Microsoft actually implements similar checks in the Windows Server 2003 SP1
* pool code, but only for checked builds.
*
* As of Vista, however, an MSDN Blog entry by a Security Team Manager indicates
* that these checks are done even on retail builds, due to the increasing
* number of kernel-mode attacks which depend on dangling list pointers and other
* kinds of list-based attacks.
*
* For now, I will leave these checks on all the time, but later they are likely
* to be DBG-only, at least until there are enough kernel-mode security attacks
* against ReactOS to warrant the performance hit.
*
* For now, these are not made inline, so we can get good stack traces.
*/
PLIST_ENTRY
NTAPI
ExpDecodePoolLink(IN PLIST_ENTRY Link)
{
return (PLIST_ENTRY)((ULONG_PTR)Link & ~1);
}
PLIST_ENTRY
NTAPI
ExpEncodePoolLink(IN PLIST_ENTRY Link)
{
return (PLIST_ENTRY)((ULONG_PTR)Link | 1);
}
VOID
NTAPI
ExpCheckPoolLinks(IN PLIST_ENTRY ListHead)
{
if ((ExpDecodePoolLink(ExpDecodePoolLink(ListHead->Flink)->Blink) != ListHead) ||
(ExpDecodePoolLink(ExpDecodePoolLink(ListHead->Blink)->Flink) != ListHead))
{
KeBugCheckEx(BAD_POOL_HEADER,
3,
(ULONG_PTR)ListHead,
(ULONG_PTR)ExpDecodePoolLink(ExpDecodePoolLink(ListHead->Flink)->Blink),
(ULONG_PTR)ExpDecodePoolLink(ExpDecodePoolLink(ListHead->Blink)->Flink));
}
}
VOID
NTAPI
ExpInitializePoolListHead(IN PLIST_ENTRY ListHead)
{
ListHead->Flink = ListHead->Blink = ExpEncodePoolLink(ListHead);
}
BOOLEAN
NTAPI
ExpIsPoolListEmpty(IN PLIST_ENTRY ListHead)
{
return (ExpDecodePoolLink(ListHead->Flink) == ListHead);
}
VOID
NTAPI
ExpRemovePoolEntryList(IN PLIST_ENTRY Entry)
{
PLIST_ENTRY Blink, Flink;
Flink = ExpDecodePoolLink(Entry->Flink);
Blink = ExpDecodePoolLink(Entry->Blink);
Flink->Blink = ExpEncodePoolLink(Blink);
Blink->Flink = ExpEncodePoolLink(Flink);
}
PLIST_ENTRY
NTAPI
ExpRemovePoolHeadList(IN PLIST_ENTRY ListHead)
{
PLIST_ENTRY Entry, Flink;
Entry = ExpDecodePoolLink(ListHead->Flink);
Flink = ExpDecodePoolLink(Entry->Flink);
ListHead->Flink = ExpEncodePoolLink(Flink);
Flink->Blink = ExpEncodePoolLink(ListHead);
return Entry;
}
PLIST_ENTRY
NTAPI
ExpRemovePoolTailList(IN PLIST_ENTRY ListHead)
{
PLIST_ENTRY Entry, Blink;
Entry = ExpDecodePoolLink(ListHead->Blink);
Blink = ExpDecodePoolLink(Entry->Blink);
ListHead->Blink = ExpEncodePoolLink(Blink);
Blink->Flink = ExpEncodePoolLink(ListHead);
return Entry;
}
VOID
NTAPI
ExpInsertPoolTailList(IN PLIST_ENTRY ListHead,
IN PLIST_ENTRY Entry)
{
PLIST_ENTRY Blink;
ExpCheckPoolLinks(ListHead);
Blink = ExpDecodePoolLink(ListHead->Blink);
Entry->Flink = ExpEncodePoolLink(ListHead);
Entry->Blink = ExpEncodePoolLink(Blink);
Blink->Flink = ExpEncodePoolLink(Entry);
ListHead->Blink = ExpEncodePoolLink(Entry);
ExpCheckPoolLinks(ListHead);
}
VOID
NTAPI
ExpInsertPoolHeadList(IN PLIST_ENTRY ListHead,
IN PLIST_ENTRY Entry)
{
PLIST_ENTRY Flink;
ExpCheckPoolLinks(ListHead);
Flink = ExpDecodePoolLink(ListHead->Flink);
Entry->Flink = ExpEncodePoolLink(Flink);
Entry->Blink = ExpEncodePoolLink(ListHead);
Flink->Blink = ExpEncodePoolLink(Entry);
ListHead->Flink = ExpEncodePoolLink(Entry);
ExpCheckPoolLinks(ListHead);
}
VOID
NTAPI
ExpCheckPoolHeader(IN PPOOL_HEADER Entry)
{
PPOOL_HEADER PreviousEntry, NextEntry;
/* Is there a block before this one? */
if (Entry->PreviousSize)
{
/* Get it */
PreviousEntry = POOL_PREV_BLOCK(Entry);
/* The two blocks must be on the same page! */
if (PAGE_ALIGN(Entry) != PAGE_ALIGN(PreviousEntry))
{
/* Something is awry */
KeBugCheckEx(BAD_POOL_HEADER,
6,
(ULONG_PTR)PreviousEntry,
__LINE__,
(ULONG_PTR)Entry);
}
/* This block should also indicate that it's as large as we think it is */
if (PreviousEntry->BlockSize != Entry->PreviousSize)
{
/* Otherwise, someone corrupted one of the sizes */
KeBugCheckEx(BAD_POOL_HEADER,
5,
(ULONG_PTR)PreviousEntry,
__LINE__,
(ULONG_PTR)Entry);
}
}
else if (PAGE_ALIGN(Entry) != Entry)
{
/* If there's no block before us, we are the first block, so we should be on a page boundary */
KeBugCheckEx(BAD_POOL_HEADER,
7,
0,
__LINE__,
(ULONG_PTR)Entry);
}
/* This block must have a size */
if (!Entry->BlockSize)
{
/* Someone must've corrupted this field */
KeBugCheckEx(BAD_POOL_HEADER,
8,
0,
__LINE__,
(ULONG_PTR)Entry);
}
/* Okay, now get the next block */
NextEntry = POOL_NEXT_BLOCK(Entry);
/* If this is the last block, then we'll be page-aligned, otherwise, check this block */
if (PAGE_ALIGN(NextEntry) != NextEntry)
{
/* The two blocks must be on the same page! */
if (PAGE_ALIGN(Entry) != PAGE_ALIGN(NextEntry))
{
/* Something is messed up */
KeBugCheckEx(BAD_POOL_HEADER,
9,
(ULONG_PTR)NextEntry,
__LINE__,
(ULONG_PTR)Entry);
}
/* And this block should think we are as large as we truly are */
if (NextEntry->PreviousSize != Entry->BlockSize)
{
/* Otherwise, someone corrupted the field */
KeBugCheckEx(BAD_POOL_HEADER,
5,
(ULONG_PTR)NextEntry,
__LINE__,
(ULONG_PTR)Entry);
}
}
}
VOID
NTAPI
ExpCheckPoolBlocks(IN PVOID Block)
{
BOOLEAN FoundBlock;
SIZE_T Size = 0;
PPOOL_HEADER Entry;
/* Get the first entry for this page, make sure it really is the first */
Entry = PAGE_ALIGN(Block);
ASSERT(Entry->PreviousSize == 0);
/* Now scan each entry */
while (TRUE)
{
/* When we actually found our block, remember this */
if (Entry == Block) FoundBlock = TRUE;
/* Now validate this block header */
ExpCheckPoolHeader(Entry);
/* And go to the next one, keeping track of our size */
Size += Entry->BlockSize;
Entry = POOL_NEXT_BLOCK(Entry);
/* If we hit the last block, stop */
if (Size >= (PAGE_SIZE / POOL_BLOCK_SIZE)) break;
/* If we hit the end of the page, stop */
if (PAGE_ALIGN(Entry) == Entry) break;
}
/* We must've found our block, and we must have hit the end of the page */
if ((PAGE_ALIGN(Entry) != Entry) || !(FoundBlock))
{
/* Otherwise, the blocks are messed up */
KeBugCheckEx(BAD_POOL_HEADER, 10, (ULONG_PTR)Block, __LINE__, (ULONG_PTR)Entry);
}
}
/* PRIVATE FUNCTIONS **********************************************************/
VOID
NTAPI
ExInitializePoolDescriptor(IN PPOOL_DESCRIPTOR PoolDescriptor,
IN POOL_TYPE PoolType,
IN ULONG PoolIndex,
IN ULONG Threshold,
IN PVOID PoolLock)
{
PLIST_ENTRY NextEntry, LastEntry;
//
// Setup the descriptor based on the caller's request
//
PoolDescriptor->PoolType = PoolType;
PoolDescriptor->PoolIndex = PoolIndex;
PoolDescriptor->Threshold = Threshold;
PoolDescriptor->LockAddress = PoolLock;
//
// Initialize accounting data
//
PoolDescriptor->RunningAllocs = 0;
PoolDescriptor->RunningDeAllocs = 0;
PoolDescriptor->TotalPages = 0;
PoolDescriptor->TotalBytes = 0;
PoolDescriptor->TotalBigPages = 0;
//
// Nothing pending for now
//
PoolDescriptor->PendingFrees = NULL;
PoolDescriptor->PendingFreeDepth = 0;
//
// Loop all the descriptor's allocation lists and initialize them
//
NextEntry = PoolDescriptor->ListHeads;
LastEntry = NextEntry + POOL_LISTS_PER_PAGE;
while (NextEntry < LastEntry)
{
ExpInitializePoolListHead(NextEntry);
NextEntry++;
}
}
VOID
NTAPI
InitializePool(IN POOL_TYPE PoolType,
IN ULONG Threshold)
{
PPOOL_DESCRIPTOR Descriptor;
//
// Check what kind of pool this is
//
if (PoolType == NonPagedPool)
{
//
// Initialize the nonpaged pool descriptor
//
PoolVector[NonPagedPool] = &NonPagedPoolDescriptor;
ExInitializePoolDescriptor(PoolVector[NonPagedPool],
NonPagedPool,
0,
Threshold,
NULL);
}
else
{
//
// Allocate the pool descriptor
//
Descriptor = ExAllocatePoolWithTag(NonPagedPool,
sizeof(KGUARDED_MUTEX) +
sizeof(POOL_DESCRIPTOR),
'looP');
if (!Descriptor)
{
//
// This is really bad...
//
KeBugCheckEx(MUST_SUCCEED_POOL_EMPTY,
0,
-1,
-1,
-1);
}
//
// Setup the vector and guarded mutex for paged pool
//
PoolVector[PagedPool] = Descriptor;
ExpPagedPoolMutex = (PKGUARDED_MUTEX)(Descriptor + 1);
KeInitializeGuardedMutex(ExpPagedPoolMutex);
ExInitializePoolDescriptor(Descriptor,
PagedPool,
0,
Threshold,
ExpPagedPoolMutex);
}
}
FORCEINLINE
KIRQL
ExLockPool(IN PPOOL_DESCRIPTOR Descriptor)
{
//
// Check if this is nonpaged pool
//
if ((Descriptor->PoolType & BASE_POOL_TYPE_MASK) == NonPagedPool)
{
//
// Use the queued spin lock
//
return KeAcquireQueuedSpinLock(LockQueueNonPagedPoolLock);
}
else
{
//
// Use the guarded mutex
//
KeAcquireGuardedMutex(Descriptor->LockAddress);
return APC_LEVEL;
}
}
FORCEINLINE
VOID
ExUnlockPool(IN PPOOL_DESCRIPTOR Descriptor,
IN KIRQL OldIrql)
{
//
// Check if this is nonpaged pool
//
if ((Descriptor->PoolType & BASE_POOL_TYPE_MASK) == NonPagedPool)
{
//
// Use the queued spin lock
//
KeReleaseQueuedSpinLock(LockQueueNonPagedPoolLock, OldIrql);
}
else
{
//
// Use the guarded mutex
//
KeReleaseGuardedMutex(Descriptor->LockAddress);
}
}
/* PUBLIC FUNCTIONS ***********************************************************/
/*
* @implemented
*/
PVOID
NTAPI
ExAllocatePoolWithTag(IN POOL_TYPE PoolType,
IN SIZE_T NumberOfBytes,
IN ULONG Tag)
{
PPOOL_DESCRIPTOR PoolDesc;
PLIST_ENTRY ListHead;
PPOOL_HEADER Entry, NextEntry, FragmentEntry;
KIRQL OldIrql;
ULONG BlockSize, i;
//
// Check for paged pool
//
if (!(AllowPagedPool) && (PoolType == PagedPool)) return ExAllocatePagedPoolWithTag(PagedPool, NumberOfBytes, Tag);
//
// Some sanity checks
//
ASSERT(Tag != 0);
ASSERT(Tag != ' GIB');
ASSERT(NumberOfBytes != 0);
//
// Get the pool type and its corresponding vector for this request
//
PoolType = PoolType & BASE_POOL_TYPE_MASK;
PoolDesc = PoolVector[PoolType];
ASSERT(PoolDesc != NULL);
//
// Check if this is a big page allocation
//
if (NumberOfBytes > POOL_MAX_ALLOC)
{
//
// Then just return the number of pages requested
//
return MiAllocatePoolPages(PoolType, NumberOfBytes);
}
//
// Should never request 0 bytes from the pool, but since so many drivers do
// it, we'll just assume they want 1 byte, based on NT's similar behavior
//
if (!NumberOfBytes) NumberOfBytes = 1;
//
// A pool allocation is defined by its data, a linked list to connect it to
// the free list (if necessary), and a pool header to store accounting info.
// Calculate this size, then convert it into a block size (units of pool
// headers)
//
// Note that i cannot overflow (past POOL_LISTS_PER_PAGE) because any such
// request would've been treated as a POOL_MAX_ALLOC earlier and resulted in
// the direct allocation of pages.
//
i = (NumberOfBytes + sizeof(POOL_HEADER) + (POOL_BLOCK_SIZE - 1)) / POOL_BLOCK_SIZE;
//
// Loop in the free lists looking for a block if this size. Start with the
// list optimized for this kind of size lookup
//
ListHead = &PoolDesc->ListHeads[i];
do
{
//
// Are there any free entries available on this list?
//
if (!ExpIsPoolListEmpty(ListHead))
{
//
// Acquire the pool lock now
//
OldIrql = ExLockPool(PoolDesc);
//
// And make sure the list still has entries
//
if (ExpIsPoolListEmpty(ListHead))
{
//
// Someone raced us (and won) before we had a chance to acquire
// the lock.
//
// Try again!
//
ExUnlockPool(PoolDesc, OldIrql);
ListHead++;
continue;
}
//
// Remove a free entry from the list
// Note that due to the way we insert free blocks into multiple lists
// there is a guarantee that any block on this list will either be
// of the correct size, or perhaps larger.
//
ExpCheckPoolLinks(ListHead);
Entry = POOL_ENTRY(ExpRemovePoolHeadList(ListHead));
ExpCheckPoolLinks(ListHead);
ExpCheckPoolBlocks(Entry);
ASSERT(Entry->BlockSize >= i);
ASSERT(Entry->PoolType == 0);
//
// Check if this block is larger that what we need. The block could
// not possibly be smaller, due to the reason explained above (and
// we would've asserted on a checked build if this was the case).
//
if (Entry->BlockSize != i)
{
//
// Is there an entry before this one?
//
if (Entry->PreviousSize == 0)
{
//
// There isn't anyone before us, so take the next block and
// turn it into a fragment that contains the leftover data
// that we don't need to satisfy the caller's request
//
FragmentEntry = POOL_BLOCK(Entry, i);
FragmentEntry->BlockSize = Entry->BlockSize - i;
//
// And make it point back to us
//
FragmentEntry->PreviousSize = i;
//
// Now get the block that follows the new fragment and check
// if it's still on the same page as us (and not at the end)
//
NextEntry = POOL_NEXT_BLOCK(FragmentEntry);
if (PAGE_ALIGN(NextEntry) != NextEntry)
{
//
// Adjust this next block to point to our newly created
// fragment block
//
NextEntry->PreviousSize = FragmentEntry->BlockSize;
}
}
else
{
//
// There is a free entry before us, which we know is smaller
// so we'll make this entry the fragment instead
//
FragmentEntry = Entry;
//
// And then we'll remove from it the actual size required.
// Now the entry is a leftover free fragment
//
Entry->BlockSize -= i;
//
// Now let's go to the next entry after the fragment (which
// used to point to our original free entry) and make it
// reference the new fragment entry instead.
//
// This is the entry that will actually end up holding the
// allocation!
//
Entry = POOL_NEXT_BLOCK(Entry);
Entry->PreviousSize = FragmentEntry->BlockSize;
//
// And now let's go to the entry after that one and check if
// it's still on the same page, and not at the end
//
NextEntry = POOL_BLOCK(Entry, i);
if (PAGE_ALIGN(NextEntry) != NextEntry)
{
//
// Make it reference the allocation entry
//
NextEntry->PreviousSize = i;
}
}
//
// Now our (allocation) entry is the right size
//
Entry->BlockSize = i;
//
// And the next entry is now the free fragment which contains
// the remaining difference between how big the original entry
// was, and the actual size the caller needs/requested.
//
FragmentEntry->PoolType = 0;
BlockSize = FragmentEntry->BlockSize;
//
// Now check if enough free bytes remained for us to have a
// "full" entry, which contains enough bytes for a linked list
// and thus can be used for allocations (up to 8 bytes...)
//
ExpCheckPoolLinks(&PoolDesc->ListHeads[BlockSize - 1]);
if (BlockSize != 1)
{
//
// Insert the free entry into the free list for this size
//
ExpInsertPoolTailList(&PoolDesc->ListHeads[BlockSize - 1],
POOL_FREE_BLOCK(FragmentEntry));
ExpCheckPoolLinks(POOL_FREE_BLOCK(FragmentEntry));
}
}
//
// We have found an entry for this allocation, so set the pool type
// and release the lock since we're done
//
Entry->PoolType = PoolType + 1;
ExpCheckPoolBlocks(Entry);
ExUnlockPool(PoolDesc, OldIrql);
//
// Return the pool allocation
//
Entry->PoolTag = Tag;
(POOL_FREE_BLOCK(Entry))->Flink = NULL;
(POOL_FREE_BLOCK(Entry))->Blink = NULL;
return POOL_FREE_BLOCK(Entry);
}
} while (++ListHead != &PoolDesc->ListHeads[POOL_LISTS_PER_PAGE]);
//
// There were no free entries left, so we have to allocate a new fresh page
//
Entry = MiAllocatePoolPages(PoolType, PAGE_SIZE);
ASSERT(Entry != NULL);
Entry->Ulong1 = 0;
Entry->BlockSize = i;
Entry->PoolType = PoolType + 1;
//
// This page will have two entries -- one for the allocation (which we just
// created above), and one for the remaining free bytes, which we're about
// to create now. The free bytes are the whole page minus what was allocated
// and then converted into units of block headers.
//
BlockSize = (PAGE_SIZE / POOL_BLOCK_SIZE) - i;
FragmentEntry = POOL_BLOCK(Entry, i);
FragmentEntry->Ulong1 = 0;
FragmentEntry->BlockSize = BlockSize;
FragmentEntry->PreviousSize = i;
//
// Now check if enough free bytes remained for us to have a "full" entry,
// which contains enough bytes for a linked list and thus can be used for
// allocations (up to 8 bytes...)
//
if (FragmentEntry->BlockSize != 1)
{
//
// Excellent -- acquire the pool lock
//
OldIrql = ExLockPool(PoolDesc);
//
// And insert the free entry into the free list for this block size
//
ExpCheckPoolLinks(&PoolDesc->ListHeads[BlockSize - 1]);
ExpInsertPoolTailList(&PoolDesc->ListHeads[BlockSize - 1],
POOL_FREE_BLOCK(FragmentEntry));
ExpCheckPoolLinks(POOL_FREE_BLOCK(FragmentEntry));
//
// Release the pool lock
//
ExpCheckPoolBlocks(Entry);
ExUnlockPool(PoolDesc, OldIrql);
}
//
// And return the pool allocation
//
ExpCheckPoolBlocks(Entry);
Entry->PoolTag = Tag;
return POOL_FREE_BLOCK(Entry);
}
/*
* @implemented
*/
PVOID
NTAPI
ExAllocatePool(POOL_TYPE PoolType,
SIZE_T NumberOfBytes)
{
//
// Use a default tag of "None"
//
return ExAllocatePoolWithTag(PoolType, NumberOfBytes, 'enoN');
}
/*
* @implemented
*/
VOID
NTAPI
ExFreePoolWithTag(IN PVOID P,
IN ULONG TagToFree)
{
PPOOL_HEADER Entry, NextEntry;
ULONG BlockSize;
KIRQL OldIrql;
POOL_TYPE PoolType;
PPOOL_DESCRIPTOR PoolDesc;
BOOLEAN Combined = FALSE;
//
// Check for paged pool
//
if ((P >= MmPagedPoolBase) &&
(P <= (PVOID)((ULONG_PTR)MmPagedPoolBase + MmPagedPoolSize)))
{
//
// Use old allocator
//
ExFreePagedPool(P);
return;
}
//
// Quickly deal with big page allocations
//
if (PAGE_ALIGN(P) == P)
{
MiFreePoolPages(P);
return;
}
//
// Get the entry for this pool allocation
// The pointer math here may look wrong or confusing, but it is quite right
//
Entry = P;
Entry--;
//
// Get the size of the entry, and it's pool type, then load the descriptor
// for this pool type
//
BlockSize = Entry->BlockSize;
PoolType = (Entry->PoolType - 1) & BASE_POOL_TYPE_MASK;
PoolDesc = PoolVector[PoolType];
//
// Get the pointer to the next entry
//
NextEntry = POOL_BLOCK(Entry, BlockSize);
//
// Acquire the pool lock
//
OldIrql = ExLockPool(PoolDesc);
//
// Check if the next allocation is at the end of the page
//
ExpCheckPoolBlocks(Entry);
if (PAGE_ALIGN(NextEntry) != NextEntry)
{
//
// We may be able to combine the block if it's free
//
if (NextEntry->PoolType == 0)
{
//
// The next block is free, so we'll do a combine
//
Combined = TRUE;
//
// Make sure there's actual data in the block -- anything smaller
// than this means we only have the header, so there's no linked list
// for us to remove
//
if ((NextEntry->BlockSize != 1))
{
//
// The block is at least big enough to have a linked list, so go
// ahead and remove it
//
ExpCheckPoolLinks(POOL_FREE_BLOCK(NextEntry));
ExpRemovePoolEntryList(POOL_FREE_BLOCK(NextEntry));
ExpCheckPoolLinks(ExpDecodePoolLink((POOL_FREE_BLOCK(NextEntry))->Flink));
ExpCheckPoolLinks(ExpDecodePoolLink((POOL_FREE_BLOCK(NextEntry))->Blink));
}
//
// Our entry is now combined with the next entry
//
Entry->BlockSize = Entry->BlockSize + NextEntry->BlockSize;
}
}
//
// Now check if there was a previous entry on the same page as us
//
if (Entry->PreviousSize)
{
//
// Great, grab that entry and check if it's free
//
NextEntry = POOL_PREV_BLOCK(Entry);
if (NextEntry->PoolType == 0)
{
//
// It is, so we can do a combine
//
Combined = TRUE;
//
// Make sure there's actual data in the block -- anything smaller
// than this means we only have the header so there's no linked list
// for us to remove
//
if ((NextEntry->BlockSize != 1))
{
//
// The block is at least big enough to have a linked list, so go
// ahead and remove it
//
ExpCheckPoolLinks(POOL_FREE_BLOCK(NextEntry));
ExpRemovePoolEntryList(POOL_FREE_BLOCK(NextEntry));
ExpCheckPoolLinks(ExpDecodePoolLink((POOL_FREE_BLOCK(NextEntry))->Flink));
ExpCheckPoolLinks(ExpDecodePoolLink((POOL_FREE_BLOCK(NextEntry))->Blink));
}
//
// Combine our original block (which might've already been combined
// with the next block), into the previous block
//
NextEntry->BlockSize = NextEntry->BlockSize + Entry->BlockSize;
//
// And now we'll work with the previous block instead
//
Entry = NextEntry;
}
}
//
// By now, it may have been possible for our combined blocks to actually
// have made up a full page (if there were only 2-3 allocations on the
// page, they could've all been combined).
//
if ((PAGE_ALIGN(Entry) == Entry) &&
(PAGE_ALIGN(POOL_NEXT_BLOCK(Entry)) == POOL_NEXT_BLOCK(Entry)))
{
//
// In this case, release the pool lock, and free the page
//
ExUnlockPool(PoolDesc, OldIrql);
MiFreePoolPages(Entry);
return;
}
//
// Otherwise, we now have a free block (or a combination of 2 or 3)
//
Entry->PoolType = 0;
BlockSize = Entry->BlockSize;
ASSERT(BlockSize != 1);
//
// Check if we actually did combine it with anyone
//
if (Combined)
{
//
// Get the first combined block (either our original to begin with, or
// the one after the original, depending if we combined with the previous)
//
NextEntry = POOL_NEXT_BLOCK(Entry);
//
// As long as the next block isn't on a page boundary, have it point
// back to us
//
if (PAGE_ALIGN(NextEntry) != NextEntry) NextEntry->PreviousSize = BlockSize;
}
//
// Insert this new free block, and release the pool lock
//
ExpInsertPoolHeadList(&PoolDesc->ListHeads[BlockSize - 1], POOL_FREE_BLOCK(Entry));
ExpCheckPoolLinks(POOL_FREE_BLOCK(Entry));
ExUnlockPool(PoolDesc, OldIrql);
}
/*
* @implemented
*/
VOID
NTAPI
ExFreePool(PVOID P)
{
//
// Just free without checking for the tag
//
ExFreePoolWithTag(P, 0);
}
/*
* @unimplemented
*/
SIZE_T
NTAPI
ExQueryPoolBlockSize(IN PVOID PoolBlock,
OUT PBOOLEAN QuotaCharged)
{
//
// Not implemented
//
UNIMPLEMENTED;
return FALSE;
}
/*
* @implemented
*/
PVOID
NTAPI
ExAllocatePoolWithQuota(IN POOL_TYPE PoolType,
IN SIZE_T NumberOfBytes)
{
//
// Allocate the pool
//
return ExAllocatePoolWithQuotaTag(PoolType, NumberOfBytes, 'enoN');
}
/*
* @implemented
*/
PVOID
NTAPI
ExAllocatePoolWithTagPriority(IN POOL_TYPE PoolType,
IN SIZE_T NumberOfBytes,
IN ULONG Tag,
IN EX_POOL_PRIORITY Priority)
{
//
// Allocate the pool
//
UNIMPLEMENTED;
return ExAllocatePoolWithTag(PoolType, NumberOfBytes, Tag);
}
/*
* @implemented
*/
PVOID
NTAPI
ExAllocatePoolWithQuotaTag(IN POOL_TYPE PoolType,
IN SIZE_T NumberOfBytes,
IN ULONG Tag)
{
//
// Allocate the pool
//
UNIMPLEMENTED;
return ExAllocatePoolWithTag(PoolType, NumberOfBytes, Tag);
}
/* EOF */
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