windows-nt/Source/XPSP1/NT/net/rras/ndis/raspti/ppool.c

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2020-09-26 03:20:57 -05:00
// Copyright (c) 1997, Microsoft Corporation, all rights reserved
//
// ppool.c
// RAS L2TP WAN mini-port/call-manager driver
// Packet pool management routines
//
// 01/07/97 Steve Cobb, adapted from Gurdeep's WANARP code.
#include "ptiwan.h"
//-----------------------------------------------------------------------------
// Local prototypes (alphabetically)
//-----------------------------------------------------------------------------
PACKETHEAD*
AddPacketBlockToPool(
IN PACKETPOOL* pPool );
VOID
FreeUnusedPacketPoolBlocks(
IN PACKETPOOL* pPool );
//-----------------------------------------------------------------------------
// Interface routines
//-----------------------------------------------------------------------------
VOID
InitPacketPool(
OUT PACKETPOOL* pPool,
IN ULONG ulProtocolReservedLength,
IN ULONG ulMaxPackets,
IN ULONG ulPacketsPerBlock,
IN ULONG ulFreesPerCollection,
IN ULONG ulTag )
// Initialize caller's packet pool control block 'pPool'.
// 'UlProtocolReservedLength' is the size in bytes of the
// 'ProtocolReserved' array of each individual packet. 'UlMaxPackets' is
// the maximum number of packets allowed in the entire pool, or 0 for
// unlimited. 'UlPacketsPerBlock' is the number of packets to include in
// each block of packets. 'UlFreesPerCollection' is the number of
// FreePacketToPool calls until the next garbage collect scan, or 0 for
// default. 'UlTag' is the memory identification tag to use when
// allocating blocks.
//
// IMPORTANT: Caller's 'pPool' packet must be protected from multiple
// access during this call.
//
{
pPool->ulProtocolReservedLength = ulProtocolReservedLength;
pPool->ulPacketsPerBlock = ulPacketsPerBlock;
pPool->ulMaxPackets = ulMaxPackets;
pPool->ulFreesSinceCollection = 0;
pPool->ulTag = ulTag;
if (ulFreesPerCollection)
{
pPool->ulFreesPerCollection = ulFreesPerCollection;
}
else
{
// Calculate default garbage collection trigger. Don't want to be too
// aggressive here.
//
pPool->ulFreesPerCollection = 50 * pPool->ulPacketsPerBlock;
}
TRACE( TL_N, TM_Pool, ( "InitPp tag=$%08x pr=%d cnt=%d",
pPool->ulTag,
pPool->ulProtocolReservedLength,
pPool->ulPacketsPerBlock ) );
InitializeListHead( &pPool->listBlocks );
InitializeListHead( &pPool->listFreePackets );
NdisAllocateSpinLock( &pPool->lock );
}
BOOLEAN
FreePacketPool(
IN PACKETPOOL* pPool )
// Free up all resources allocated in packet pool 'pPool'. This is the
// inverse of InitPacketPool.
//
// Returns true if successful, false if any of the pool could not be freed
// due to outstanding packets.
//
{
BOOLEAN fSuccess;
TRACE( TL_N, TM_Pool, ( "FreePp" ) );
NdisAcquireSpinLock( &pPool->lock );
{
FreeUnusedPacketPoolBlocks( pPool );
fSuccess = (pPool->ulCurPackets == 0);
}
NdisReleaseSpinLock( &pPool->lock );
return fSuccess;
}
NDIS_PACKET*
GetPacketFromPool(
IN PACKETPOOL* pPool,
OUT PACKETHEAD** ppHead )
// Returns the address of the NDIS_PACKET descriptor allocated from the
// pool 'pPool'. The pool is expanded, if necessary, but caller should
// still check for NULL return since the pool may have been at maximum
// size. 'PpHead' is the "cookie" that is used to return the packet to
// the pool (see FreePacketToPool). Caller would normally stash this
// value in the appropriate 'reserved' areas of the packet for retrieval
// later.
//
{
LIST_ENTRY* pLink;
PACKETHEAD* pHead;
NDIS_PACKET* pPacket;
NdisAcquireSpinLock( &pPool->lock );
{
if (IsListEmpty( &pPool->listFreePackets ))
{
pLink = NULL;
}
else
{
pLink = RemoveHeadList( &pPool->listFreePackets );
pHead = CONTAINING_RECORD( pLink, PACKETHEAD, linkFreePackets );
--pHead->pBlock->ulFreePackets;
}
}
NdisReleaseSpinLock( &pPool->lock );
if (!pLink)
{
// The free list was empty. Try to expand the pool.
//
pHead = AddPacketBlockToPool( pPool );
if (!pHead)
{
TRACE( TL_A, TM_Pool, ( "GetPfP failed?" ) );
return NULL;
}
}
TRACE( TL_N, TM_Pool,
( "GetPfP=$%p/h=$%p, %d free",
pHead->pNdisPacket, pHead, pHead->pBlock->ulFreePackets ) );
*ppHead = pHead;
return pHead->pNdisPacket;
}
VOID
FreePacketToPool(
IN PACKETPOOL* pPool,
IN PACKETHEAD* pHead,
IN BOOLEAN fGarbageCollection )
// Returns 'pPacket' to the pool of unused packets 'pPool'. 'PPacket'
// must have been previously allocated with GetPacketFromPool.
// 'FGarbageCollection' is set when the free should be considered for
// purposes of garbage collection. This is used by the AddPacketToPool
// routine to avoid counting the initial "add" frees. Normal callers
// should set this flag.
//
{
DBG_if (fGarbageCollection)
{
TRACE( TL_N, TM_Pool,
( "FreePtoP($%p,h=$%p) %d free",
pHead->pNdisPacket, pHead, pHead->pBlock->ulFreePackets ) );
}
NdisAcquireSpinLock( &pPool->lock );
{
InsertHeadList( &pPool->listFreePackets, &pHead->linkFreePackets );
++pHead->pBlock->ulFreePackets;
if (fGarbageCollection)
{
++pPool->ulFreesSinceCollection;
if (pPool->ulFreesSinceCollection >= pPool->ulFreesPerCollection)
{
// Time to collect garbage, i.e. free any blocks in the pool
// not in use.
//
FreeUnusedPacketPoolBlocks( pPool );
pPool->ulFreesSinceCollection = 0;
}
}
}
NdisReleaseSpinLock( &pPool->lock );
}
//-----------------------------------------------------------------------------
// Utility routines (alphabetically)
//-----------------------------------------------------------------------------
PACKETHEAD*
AddPacketBlockToPool(
IN PACKETPOOL* pPool )
// Allocate a new packet block and add it to the packet pool 'pPool'.
//
// Returns the PACKETHEAD allocated from the pool or NULL if none.
//
{
NDIS_STATUS status;
PACKETBLOCKHEAD* pNew;
ULONG ulSize;
ULONG ulCount;
BOOLEAN fOk;
PACKETHEAD* pReturn;
TRACE( TL_A, TM_Pool, ( "AddPpBlock(%d+%d)",
pPool->ulCurPackets, pPool->ulPacketsPerBlock ) );
fOk = FALSE;
pNew = NULL;
NdisAcquireSpinLock( &pPool->lock );
{
do
{
if (pPool->ulMaxPackets
&& pPool->ulCurPackets >= pPool->ulMaxPackets)
{
// No can do. The pool's already at maximum size.
//
TRACE( TL_A, TM_Pool, ( "Pp maxed?" ) );
break;
}
// Calculate the contiguous block's size and the number of packets
// it will hold.
//
ulCount = pPool->ulPacketsPerBlock;
if (pPool->ulMaxPackets)
{
if (ulCount > pPool->ulMaxPackets - pPool->ulCurPackets)
ulCount = pPool->ulMaxPackets - pPool->ulCurPackets;
}
ulSize = sizeof(PACKETBLOCKHEAD) + (ulCount * sizeof(PACKETHEAD));
// Allocate the contiguous memory block for the PACKETBLOCK header
// and the individual PACKETHEADs.
//
pNew = ALLOC_NONPAGED( ulSize, pPool->ulTag );
if (!pNew)
{
TRACE( TL_A, TM_Pool, ( "Alloc PB?") );
break;
}
/* Zero only the block header portion.
*/
NdisZeroMemory( pNew, sizeof(PACKETBLOCKHEAD) );
// Allocate a pool of NDIS_PACKET descriptors.
//
NdisAllocatePacketPool(
&status,
&pNew->hNdisPool,
ulCount,
pPool->ulProtocolReservedLength );
if (status != NDIS_STATUS_SUCCESS)
{
TRACE( TL_A, TM_Pool, ( "AllocPp=$%p?", status ) );
break;
}
// Fill in the back pointer to the pool.
//
pNew->pPool = pPool;
// Link the new block. At this point, all the packets are
// effectively "in use". They are made available in the loop
// below.
//
pNew->ulPackets = ulCount;
pPool->ulCurPackets += ulCount;
InsertHeadList( &pPool->listBlocks, &pNew->linkBlocks );
fOk = TRUE;
}
while (FALSE);
}
NdisReleaseSpinLock( &pPool->lock );
if (!fOk)
{
// Bailing, undo whatever succeeded.
//
if (pNew)
{
FREE_NONPAGED( pNew );
if (pNew->hNdisPool)
{
NdisFreePacketPool( pNew->hNdisPool );
}
}
return NULL;
}
// Initialize each individual packet header and add it to the list of free
// packets.
//
{
ULONG i;
PACKETHEAD* pHead;
pReturn = NULL;
// For each PACKETHEAD of the block...
//
for (i = 0, pHead = (PACKETHEAD* )(pNew + 1);
i < ulCount;
++i, ++pHead)
{
InitializeListHead( &pHead->linkFreePackets );
pHead->pBlock = pNew;
pHead->pNdisPacket = NULL;
// Associate an NDIS_PACKET descriptor from the pool we
// allocated above.
//
NdisAllocatePacket( &status, &pHead->pNdisPacket, pNew->hNdisPool );
if (status != NDIS_STATUS_SUCCESS)
{
TRACE( TL_A, TM_Pool, ( "AllocP=$%p?", status ) );
continue;
}
if (pReturn)
{
// Add the constructed packet to the list of free packets.
// The 'FALSE' tells the garbage collection algorithm the
// operation is an "add" rather than a "release" and should be
// ignored.
//
FreePacketToPool( pPool, pHead, FALSE );
}
else
{
// The first successfully constructed packet is returned by
// this routine.
//
pReturn = pHead;
}
}
}
return pReturn;
}
VOID
FreeUnusedPacketPoolBlocks(
IN PACKETPOOL* pPool )
// Check if any of the blocks in pool 'pPool' are not in use, and if so,
// free them.
//
// IMPORTANT: Caller must hold the pool lock.
//
// NOTE: The MSDN doc says that no locks may be held while calling
// NdisFreePacketXxx, but according to JameelH that is incorrect.
//
{
LIST_ENTRY* pLink;
TRACE( TL_A, TM_Pool, ( "FreeUnusedPpBlocks" ) );
// For each block in the pool...
//
pLink = pPool->listBlocks.Flink;
while (pLink != &pPool->listBlocks)
{
LIST_ENTRY* pLinkNext;
PACKETBLOCKHEAD* pBlock;
pLinkNext = pLink->Flink;
pBlock = CONTAINING_RECORD( pLink, PACKETBLOCKHEAD, linkBlocks );
if (pBlock->ulFreePackets >= pBlock->ulPackets)
{
#if 1 // Assume all buffers are free at time of call.
ULONG i;
PACKETHEAD* pHead;
TRACE( TL_A, TM_Pool, ( "FreePpBlock(%d-%d)",
pPool->ulCurPackets, pPool->ulPacketsPerBlock ) );
// Found a block with no packets in use. Walk the packet block
// removing each packet from the pool's free list and freeing any
// associated NDIS_PACKET descriptor.
//
for (i = 0, pHead = (PACKETHEAD* )(pBlock + 1);
i < pBlock->ulPackets;
++i, ++pHead)
{
RemoveEntryList( &pHead->linkFreePackets );
if (pHead->pNdisPacket)
{
NdisFreePacket( pHead->pNdisPacket );
}
}
#else // Assume some buffers may not be free at time of call.
LIST_ENTRY* pLink2;
// Found a block with no packets in use. Walk the pool's free
// list looking for buffers from this block.
//
TRACE( TL_A, TM_Pool, ( "FreePpBlock(%d-%d)",
pPool->ulCurPackets, pPool->ulPacketsPerBlock ) );
pLink2 = pPool->listFreePackets.Flink;
while (pLink2 != &pPool->listFreePackets)
{
LIST_ENTRY* pLink2Next;
PACKETHEAD* pHead;
pLink2Next = pLink2->Flink;
pHead = CONTAINING_RECORD( pLink2, PACKETHEAD, linkFreePackets );
if (pHead->pBlock == pBlock)
{
// Found a packet from the unused block. Remove it.
//
RemoveEntryList( pLink2 );
--pBlock->ulFreePackets;
if (pHead->pNdisPacket)
{
NdisFreePacket( pHead->pNdisPacket );
}
}
}
ASSERT( pBlock->ulFreePackets == 0 );
#endif
// Remove and release the unused block.
//
RemoveEntryList( pLink );
pPool->ulCurPackets -= pBlock->ulPackets;
if (pBlock->hNdisPool)
{
NdisFreePacketPool( pBlock->hNdisPool );
}
FREE_NONPAGED( pBlock );
}
pLink = pLinkNext;
}
}