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365 lines
7.4 KiB
365 lines
7.4 KiB
/*++
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Copyright (c) 20001 Microsoft Corporation
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Module Name:
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cmalloc.c
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Abstract:
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Provides routines for implementing the registry's own pool allocator.
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Author:
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Dragos C. Sambotin (DragosS) 07-Feb-2001
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Revision History:
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--*/
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#include "cmp.h"
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#ifdef ALLOC_PRAGMA
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#pragma alloc_text(INIT,CmpInitCmPrivateAlloc)
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#pragma alloc_text(PAGE,CmpDestroyCmPrivateAlloc)
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#pragma alloc_text(PAGE,CmpAllocateKeyControlBlock)
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#pragma alloc_text(PAGE,CmpFreeKeyControlBlock)
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#endif
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typedef struct _CM_ALLOC_PAGE {
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ULONG FreeCount; // number of free kcbs
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ULONG Reserved; // alignment
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#if DBG
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LIST_ENTRY CmPageListEntry;// debug only to track pages we are using
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#endif
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PVOID AllocPage; // crud allocations - this member is NOT USED
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} CM_ALLOC_PAGE, *PCM_ALLOC_PAGE;
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#define CM_KCB_ENTRY_SIZE sizeof( CM_KEY_CONTROL_BLOCK )
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#define CM_ALLOC_PAGES (PAGE_SIZE / sizeof(CM_ALLOC_ENTRY))
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#define CM_KCBS_PER_PAGE ((PAGE_SIZE - FIELD_OFFSET(CM_ALLOC_PAGE,AllocPage)) / CM_KCB_ENTRY_SIZE)
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#define KCB_TO_PAGE_ADDRESS( kcb ) (PVOID)(((ULONG_PTR)(kcb)) & ~(PAGE_SIZE - 1))
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#define KCB_TO_ALLOC_PAGE( kcb ) ((PCM_ALLOC_PAGE)KCB_TO_PAGE_ADDRESS(kcb))
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LIST_ENTRY CmpFreeKCBListHead; // list of free kcbs
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BOOLEAN CmpAllocInited = FALSE;
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#if DBG
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ULONG CmpTotalKcbUsed = 0;
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ULONG CmpTotalKcbFree = 0;
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LIST_ENTRY CmPageListHead;
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#endif
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FAST_MUTEX CmpAllocBucketLock; // used to protect the bucket
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#define LOCK_ALLOC_BUCKET() ExAcquireFastMutexUnsafe(&CmpAllocBucketLock)
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#define UNLOCK_ALLOC_BUCKET() ExReleaseFastMutexUnsafe(&CmpAllocBucketLock)
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VOID
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CmpInitCmPrivateAlloc( )
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/*++
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Routine Description:
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Initialize the CmPrivate pool allocation module
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Arguments:
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Return Value:
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--*/
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{
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if( CmpAllocInited ) {
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//
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// already inited
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//
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return;
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}
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#if DBG
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InitializeListHead(&(CmPageListHead));
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#endif //DBG
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InitializeListHead(&(CmpFreeKCBListHead));
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//
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// init the bucket lock
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//
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ExInitializeFastMutex(&CmpAllocBucketLock);
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CmpAllocInited = TRUE;
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}
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VOID
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CmpDestroyCmPrivateAlloc( )
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/*++
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Routine Description:
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Frees memory used byt the CmPrivate pool allocation module
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Arguments:
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Return Value:
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--*/
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{
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PAGED_CODE();
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if( !CmpAllocInited ) {
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return;
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}
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#if DBG
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//
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// sanity
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//
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ASSERT( CmpTotalKcbUsed == 0 );
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ASSERT( CmpTotalKcbUsed == 0 );
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ASSERT( IsListEmpty(&(CmPageListHead)) == TRUE );
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#endif
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}
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PCM_KEY_CONTROL_BLOCK
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CmpAllocateKeyControlBlock( )
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/*++
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Routine Description:
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Allocates a kcb; first try from our own allocator.
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If it doesn't work (we have maxed out our number of allocs
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or private allocator is not inited)
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try from paged pool
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Arguments:
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Return Value:
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The new kcb
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--*/
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{
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USHORT j;
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PCM_KEY_CONTROL_BLOCK kcb = NULL;
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PCM_ALLOC_PAGE AllocPage;
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PAGED_CODE();
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if( !CmpAllocInited ) {
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//
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// not inited
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//
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goto AllocFromPool;
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}
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LOCK_ALLOC_BUCKET();
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SearchFreeKcb:
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//
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// try to find a free one
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//
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if( IsListEmpty(&CmpFreeKCBListHead) == FALSE ) {
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//
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// found one
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//
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kcb = (PCM_KEY_CONTROL_BLOCK)RemoveHeadList(&CmpFreeKCBListHead);
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kcb = CONTAINING_RECORD(kcb,
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CM_KEY_CONTROL_BLOCK,
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FreeListEntry);
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AllocPage = (PCM_ALLOC_PAGE)KCB_TO_ALLOC_PAGE( kcb );
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ASSERT( AllocPage->FreeCount != 0 );
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AllocPage->FreeCount--;
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//
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// set when page was allocated
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//
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ASSERT( kcb->PrivateAlloc == 1);
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#if DBG
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CmpTotalKcbUsed++;
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CmpTotalKcbFree--;
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#endif //DBG
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UNLOCK_ALLOC_BUCKET();
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return kcb;
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}
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ASSERT( IsListEmpty(&CmpFreeKCBListHead) == TRUE );
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ASSERT( CmpTotalKcbFree == 0 );
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//
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// we need to allocate a new page as we ran out of free kcbs
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//
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//
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// allocate a new page and insert all kcbs in the freelist
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//
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AllocPage = (PCM_ALLOC_PAGE)ExAllocatePoolWithTag(PagedPool, PAGE_SIZE, CM_ALLOCATE_TAG|PROTECTED_POOL);
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if( AllocPage == NULL ) {
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//
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// we might be low on pool; maybe small pool chunks will work
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//
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UNLOCK_ALLOC_BUCKET();
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goto AllocFromPool;
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}
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//
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// set up the page
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//
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AllocPage->FreeCount = CM_KCBS_PER_PAGE;
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#if DBG
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AllocPage->Reserved = 0;
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InsertTailList(
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&CmPageListHead,
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&(AllocPage->CmPageListEntry)
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);
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#endif //DBG
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//
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// now the dirty job; insert all kcbs inside the page in the free list
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//
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for(j=0;j<CM_KCBS_PER_PAGE;j++) {
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kcb = (PCM_KEY_CONTROL_BLOCK)((PUCHAR)AllocPage + FIELD_OFFSET(CM_ALLOC_PAGE,AllocPage) + j*CM_KCB_ENTRY_SIZE);
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//
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// set it here; only once
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//
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kcb->PrivateAlloc = 1;
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InsertTailList(
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&CmpFreeKCBListHead,
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&(kcb->FreeListEntry)
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);
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}
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#if DBG
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CmpTotalKcbFree += CM_KCBS_PER_PAGE;
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#endif //DBG
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//
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// this time will find one for sure
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//
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goto SearchFreeKcb;
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AllocFromPool:
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kcb = ExAllocatePoolWithTag(PagedPool,
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sizeof(CM_KEY_CONTROL_BLOCK),
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CM_KCB_TAG | PROTECTED_POOL);
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if( kcb != NULL ) {
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//
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// clear the private alloc flag
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//
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kcb->PrivateAlloc = 0;
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}
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return kcb;
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}
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VOID
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CmpFreeKeyControlBlock( PCM_KEY_CONTROL_BLOCK kcb )
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/*++
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Routine Description:
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Frees a kcb; if it's allocated from our own pool put it back in the free list.
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If it's allocated from general pool, just free it.
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Arguments:
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kcb to free
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Return Value:
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--*/
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{
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USHORT j;
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PCM_ALLOC_PAGE AllocPage;
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PAGED_CODE();
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ASSERT_KEYBODY_LIST_EMPTY(kcb);
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if( !kcb->PrivateAlloc ) {
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//
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// just free it and be done with it
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//
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ExFreePoolWithTag(kcb, CM_KCB_TAG | PROTECTED_POOL);
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return;
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}
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LOCK_ALLOC_BUCKET();
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#if DBG
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CmpTotalKcbFree ++;
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CmpTotalKcbUsed --;
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#endif
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//
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// add kcb to freelist
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//
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InsertTailList(
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&CmpFreeKCBListHead,
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&(kcb->FreeListEntry)
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);
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//
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// get the page
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//
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AllocPage = (PCM_ALLOC_PAGE)KCB_TO_ALLOC_PAGE( kcb );
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//
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// not all are free
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//
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ASSERT( AllocPage->FreeCount != CM_KCBS_PER_PAGE);
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AllocPage->FreeCount++;
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if( AllocPage->FreeCount == CM_KCBS_PER_PAGE ) {
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//
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// entire page is free; let it go
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//
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//
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// first; iterate through the free kcb list and remove all kcbs inside this page
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//
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for(j=0;j<CM_KCBS_PER_PAGE;j++) {
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kcb = (PCM_KEY_CONTROL_BLOCK)((PUCHAR)AllocPage + FIELD_OFFSET(CM_ALLOC_PAGE,AllocPage) + j*CM_KCB_ENTRY_SIZE);
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RemoveEntryList(&(kcb->FreeListEntry));
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}
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#if DBG
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CmpTotalKcbFree -= CM_KCBS_PER_PAGE;
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RemoveEntryList(&(AllocPage->CmPageListEntry));
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#endif
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ExFreePoolWithTag(AllocPage, CM_ALLOCATE_TAG|PROTECTED_POOL);
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}
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UNLOCK_ALLOC_BUCKET();
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}
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