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/* $Id$ */
/** @file
* VBox storage devices: I/O buffer management API.
*/
/*
* Copyright (C) 2016-2017 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*/
#ifndef __IOBufMgmt_h
#define __IOBufMgmt_h
#include <VBox/cdefs.h>
#include <iprt/sg.h>
RT_C_DECLS_BEGIN
/**
* Opaque I/O buffer manager.
*/
typedef struct IOBUFMGRINT *IOBUFMGR;
/** Pointer to a I/O buffer manager. */
typedef IOBUFMGR *PIOBUFMGR;
/* NIL I/O buffer manager handle. */
#define NIL_IOBUFMGR ((IOBUFMGR)0)
#define IOBUFMGR_F_DEFAULT (0)
/** I/O buffer memory needs to be non pageable (for example because it contains sensitive data
* which shouldn't end up in swap unencrypted). */
#define IOBUFMGR_F_REQUIRE_NOT_PAGABLE RT_BIT(0)
/**
* I/O buffer descriptor.
*/
typedef struct IOBUFDESC
{
/** S/G buffer. */
RTSGBUF SgBuf;
/** Internal data */
union
{
#ifdef IOBUFDESCINT_DECLARED
IOBUFDESCINT Int;
#endif
uint8_t abPadding[HC_ARCH_BITS == 32 ? 88 : 172];
};
} IOBUFDESC;
/** Pointer to a I/O buffer descriptor. */
typedef IOBUFDESC *PIOBUFDESC;
/**
* Creates I/O buffer manager.
*
* @returns VBox status code.
* @param phIoBufMgr Where to store the handle to the I/O buffer manager on success.
* @param cbMax The maximum amount of I/O memory to allow. Trying to allocate more than
* this will lead to out of memory errors. 0 for "unlimited" size (only restriction
* is the available memory on the host).
* @param fFlags Combination of IOBUFMGR_F_*
*/
DECLHIDDEN(int) IOBUFMgrCreate(PIOBUFMGR phIoBufMgr, size_t cbMax, uint32_t fFlags);
/**
* Destroys the given I/O buffer manager.
*
* @returns VBox status code.
* @retval VERR_INVALID_STATE if there is still memory allocated by the given manager.
* @param hIoBufMgr The I/O buffer manager.
*/
DECLHIDDEN(int) IOBUFMgrDestroy(IOBUFMGR hIoBufMgr);
/**
* Allocates a I/O buffer and fills the descriptor.
*
* @returns VBox status code.
* @retval VERR_NO_MEMORY if there is not enough free memory to satisfy the request
* and partial allocations are not allowed or allocating some internal tracking
* structures failed.
* @param hIoBufMgr The I/O buffer manager.
* @param pIoBufDesc The I/O buffer descriptor to initialize on success.
* @param cbIoBuf How much to allocate.
* @param pcbIoBufAllocated Where to store amount of memory the manager was able to allocate
* if there is not enough free memory to satisfy the complete request.
* NULL if partial allocations are not supported.
*/
DECLHIDDEN(int) IOBUFMgrAllocBuf(IOBUFMGR hIoBufMgr, PIOBUFDESC pIoBufDesc, size_t cbIoBuf,
size_t *pcbIoBufAllocated);
/**
* Frees a given I/O buffer.
*
* @returns nothing.
* @param pIoBufDesc The I/O buffer descriptor to free.
*/
DECLHIDDEN(void) IOBUFMgrFreeBuf(PIOBUFDESC pIoBufDesc);
RT_C_DECLS_END
#endif /* __HBDMgmt_h */
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