/*
 * PROJECT:         ReactOS Kernel
 * LICENSE:         GPL - See COPYING in the top level directory
 * FILE:            ntoskrnl/config/cmalloc.c
 * PURPOSE:         Routines for allocating and freeing registry structures
 * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
 */

/* INCLUDES ******************************************************************/

#include <ntoskrnl.h>
#define NDEBUG
#include <debug.h>

/* GLOBALS *******************************************************************/

BOOLEAN CmpAllocInited;
KGUARDED_MUTEX CmpAllocBucketLock;
LIST_ENTRY CmpFreeKCBListHead;

KGUARDED_MUTEX CmpDelayAllocBucketLock;
LIST_ENTRY CmpFreeDelayItemsListHead;

/* FUNCTIONS *****************************************************************/

CODE_SEG("INIT")
VOID
NTAPI
CmpInitCmPrivateAlloc(VOID)
{
    /* Make sure we didn't already do this */
    if (!CmpAllocInited)
    {
        /* Setup the lock and list */
        KeInitializeGuardedMutex(&CmpAllocBucketLock);
        InitializeListHead(&CmpFreeKCBListHead);
        CmpAllocInited = TRUE;
    }
}

CODE_SEG("INIT")
VOID
NTAPI
CmpInitCmPrivateDelayAlloc(VOID)
{
    /* Initialize the delay allocation list and lock */
    KeInitializeGuardedMutex(&CmpDelayAllocBucketLock);
    InitializeListHead(&CmpFreeDelayItemsListHead);
}

VOID
NTAPI
CmpFreeKeyControlBlock(IN PCM_KEY_CONTROL_BLOCK Kcb)
{
    ULONG i;
    PCM_ALLOC_PAGE AllocPage;
    PAGED_CODE();

    /* Sanity checks */
    ASSERT(IsListEmpty(&Kcb->KeyBodyListHead) == TRUE);
    for (i = 0; i < 4; i++) ASSERT(Kcb->KeyBodyArray[i] == NULL);

    /* Check if it wasn't privately allocated */
    if (!Kcb->PrivateAlloc)
    {
        /* Free it from the pool */
        CmpFree(Kcb, TAG_KCB);
        return;
    }

    /* Acquire the private allocation lock */
    KeAcquireGuardedMutex(&CmpAllocBucketLock);

    /* Sanity check on lock ownership */
    CMP_ASSERT_HASH_ENTRY_LOCK(Kcb->ConvKey);

    /* Add us to the free list */
    InsertTailList(&CmpFreeKCBListHead, &Kcb->FreeListEntry);

    /* Get the allocation page */
    AllocPage = CmpGetAllocPageFromKcb(Kcb);

    /* Sanity check */
    ASSERT(AllocPage->FreeCount != CM_KCBS_PER_PAGE);

    /* Increase free count */
    if (++AllocPage->FreeCount == CM_KCBS_PER_PAGE)
    {
        /* Loop all the entries */
        for (i = 0; i < CM_KCBS_PER_PAGE; i++)
        {
            /* Get the KCB */
            Kcb = (PVOID)((ULONG_PTR)AllocPage +
                          FIELD_OFFSET(CM_ALLOC_PAGE, AllocPage) +
                          i * sizeof(CM_KEY_CONTROL_BLOCK));

            /* Remove the entry */
            RemoveEntryList(&Kcb->FreeListEntry);
        }

        /* Free the page */
        CmpFree(AllocPage, TAG_KCB);
    }

    /* Release the lock */
    KeReleaseGuardedMutex(&CmpAllocBucketLock);
}

PCM_KEY_CONTROL_BLOCK
NTAPI
CmpAllocateKeyControlBlock(VOID)
{
    PLIST_ENTRY NextEntry;
    PCM_KEY_CONTROL_BLOCK CurrentKcb;
    PCM_ALLOC_PAGE AllocPage;
    ULONG i;
    PAGED_CODE();

    /* Check if private allocations are initialized */
    if (CmpAllocInited)
    {
        /* They are, acquire the bucket lock */
        KeAcquireGuardedMutex(&CmpAllocBucketLock);

        /* See if there's something on the free KCB list */
SearchKcbList:
        if (!IsListEmpty(&CmpFreeKCBListHead))
        {
            /* Remove the entry */
            NextEntry = RemoveHeadList(&CmpFreeKCBListHead);

            /* Get the KCB */
            CurrentKcb = CONTAINING_RECORD(NextEntry,
                                           CM_KEY_CONTROL_BLOCK,
                                           FreeListEntry);

            /* Get the allocation page */
            AllocPage = CmpGetAllocPageFromKcb(CurrentKcb);

            /* Decrease the free count */
            ASSERT(AllocPage->FreeCount != 0);
            AllocPage->FreeCount--;

            /* Make sure this KCB is privately allocated */
            ASSERT(CurrentKcb->PrivateAlloc == 1);

            /* Release the allocation lock */
            KeReleaseGuardedMutex(&CmpAllocBucketLock);

            /* Return the KCB */
            return CurrentKcb;
        }

        /* Allocate an allocation page */
        AllocPage = CmpAllocate(PAGE_SIZE, TRUE, TAG_KCB);
        if (AllocPage)
        {
            /* Set default entries */
            AllocPage->FreeCount = CM_KCBS_PER_PAGE;

            /* Loop each entry */
            for (i = 0; i < CM_KCBS_PER_PAGE; i++)
            {
                /* Get this entry */
                CurrentKcb = (PVOID)((ULONG_PTR)AllocPage +
                                     FIELD_OFFSET(CM_ALLOC_PAGE, AllocPage) +
                                     i * sizeof(CM_KEY_CONTROL_BLOCK));

                /* Set it up */
                CurrentKcb->PrivateAlloc = TRUE;
                CurrentKcb->DelayCloseEntry = NULL;
                InsertTailList(&CmpFreeKCBListHead,
                               &CurrentKcb->FreeListEntry);
            }

            /* Now go back and search the list */
            goto SearchKcbList;
        }

        /* Release the allocation lock */
        KeReleaseGuardedMutex(&CmpAllocBucketLock);
    }

    /* Allocate a KCB only */
    CurrentKcb = CmpAllocate(sizeof(CM_KEY_CONTROL_BLOCK), TRUE, TAG_KCB);
    if (CurrentKcb)
    {
        /* Set it up */
        CurrentKcb->PrivateAlloc = 0;
        CurrentKcb->DelayCloseEntry = NULL;
    }

    /* Return it */
    return CurrentKcb;
}

PVOID
NTAPI
CmpAllocateDelayItem(VOID)
{
    PCM_DELAY_ALLOC Entry;
    PCM_ALLOC_PAGE AllocPage;
    ULONG i;
    PLIST_ENTRY NextEntry;
    PAGED_CODE();

    /* Lock the allocation buckets */
    KeAcquireGuardedMutex(&CmpDelayAllocBucketLock);

    /* Look for an item on the free list */
SearchList:
    if (!IsListEmpty(&CmpFreeDelayItemsListHead))
    {
        /* Get the current entry in the list */
        NextEntry = RemoveHeadList(&CmpFreeDelayItemsListHead);

        /* Grab the item */
        Entry = CONTAINING_RECORD(NextEntry, CM_DELAY_ALLOC, ListEntry);

        /* Clear the list */
        Entry->ListEntry.Flink = Entry->ListEntry.Blink = NULL;

        /* Grab the alloc page */
        AllocPage = CmpGetAllocPageFromDelayAlloc(Entry);

        /* Decrease free entries */
        ASSERT(AllocPage->FreeCount != 0);
        AllocPage->FreeCount--;

        /* Release the lock */
        KeReleaseGuardedMutex(&CmpDelayAllocBucketLock);
        return Entry;
    }

    /* Allocate an allocation page */
    AllocPage = CmpAllocate(PAGE_SIZE, TRUE, TAG_CM);
    if (AllocPage)
    {
        /* Set default entries */
        AllocPage->FreeCount = CM_DELAYS_PER_PAGE;

        /* Loop each entry */
        for (i = 0; i < CM_DELAYS_PER_PAGE; i++)
        {
            /* Get this entry and link it */
            Entry = (PVOID)((ULONG_PTR)AllocPage +
                            FIELD_OFFSET(CM_ALLOC_PAGE, AllocPage) +
                            i * sizeof(CM_DELAY_ALLOC));
            InsertTailList(&CmpFreeDelayItemsListHead,
                           &Entry->ListEntry);

            /* Clear the KCB pointer */
            Entry->Kcb = NULL;
        }

        /* Do the search again */
        goto SearchList;
    }

    /* Release the lock */
    KeReleaseGuardedMutex(&CmpDelayAllocBucketLock);
    return NULL;
}

VOID
NTAPI
CmpFreeDelayItem(PVOID Entry)
{
    PCM_DELAY_ALLOC AllocEntry = (PCM_DELAY_ALLOC)Entry;
    PCM_ALLOC_PAGE AllocPage;
    ULONG i;
    PAGED_CODE();

    /* Lock the table */
    KeAcquireGuardedMutex(&CmpDelayAllocBucketLock);

    /* Add the entry at the end */
    InsertTailList(&CmpFreeDelayItemsListHead, &AllocEntry->ListEntry);

    /* Get the alloc page */
    AllocPage = CmpGetAllocPageFromDelayAlloc(Entry);
    ASSERT(AllocPage->FreeCount != CM_DELAYS_PER_PAGE);

    /* Increase the number of free items */
    if (++AllocPage->FreeCount == CM_DELAYS_PER_PAGE)
    {
        /* Page is totally free now, loop each entry */
        for (i = 0; i < CM_DELAYS_PER_PAGE; i++)
        {
            /* Get the entry and unlink it */
            AllocEntry = (PVOID)((ULONG_PTR)AllocPage +
                                 FIELD_OFFSET(CM_ALLOC_PAGE, AllocPage) +
                                 i * sizeof(CM_DELAY_ALLOC));
            RemoveEntryList(&AllocEntry->ListEntry);
        }

        /* Now free the page */
        CmpFree(AllocPage, TAG_CM);
    }

    /* Release the lock */
    KeReleaseGuardedMutex(&CmpDelayAllocBucketLock);
}