1 | /* $Id: IOBufMgmt.h 106061 2024-09-16 14:03:52Z vboxsync $ */
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2 | /** @file
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3 | * VBox storage devices: I/O buffer management API.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2016-2024 Oracle and/or its affiliates.
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8 | *
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9 | * This file is part of VirtualBox base platform packages, as
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10 | * available from https://www.virtualbox.org.
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11 | *
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12 | * This program is free software; you can redistribute it and/or
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13 | * modify it under the terms of the GNU General Public License
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14 | * as published by the Free Software Foundation, in version 3 of the
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15 | * License.
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16 | *
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17 | * This program is distributed in the hope that it will be useful, but
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18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 | * General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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24 | *
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25 | * SPDX-License-Identifier: GPL-3.0-only
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26 | */
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27 |
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28 | #ifndef VBOX_INCLUDED_SRC_Storage_IOBufMgmt_h
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29 | #define VBOX_INCLUDED_SRC_Storage_IOBufMgmt_h
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30 | #ifndef RT_WITHOUT_PRAGMA_ONCE
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31 | # pragma once
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32 | #endif
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33 |
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34 | #include <VBox/cdefs.h>
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35 | #include <iprt/sg.h>
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36 |
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37 | RT_C_DECLS_BEGIN
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38 |
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39 | /**
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40 | * Opaque I/O buffer manager.
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41 | */
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42 | typedef struct IOBUFMGRINT *IOBUFMGR;
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43 | /** Pointer to a I/O buffer manager. */
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44 | typedef IOBUFMGR *PIOBUFMGR;
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45 |
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46 | /* NIL I/O buffer manager handle. */
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47 | #define NIL_IOBUFMGR ((IOBUFMGR)0)
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48 |
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49 | #define IOBUFMGR_F_DEFAULT (0)
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50 | /** I/O buffer memory needs to be non pageable (for example because it contains sensitive data
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51 | * which shouldn't end up in swap unencrypted). */
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52 | #define IOBUFMGR_F_REQUIRE_NOT_PAGABLE RT_BIT(0)
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53 |
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54 | /**
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55 | * I/O buffer descriptor.
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56 | */
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57 | typedef struct IOBUFDESC
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58 | {
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59 | /** S/G buffer. */
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60 | RTSGBUF SgBuf;
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61 | /** Internal data */
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62 | union
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63 | {
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64 | #ifdef IOBUFDESCINT_DECLARED
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65 | IOBUFDESCINT Int;
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66 | #endif
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67 | uint8_t abPadding[HC_ARCH_BITS == 32 ? 88 : 172];
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68 | };
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69 | } IOBUFDESC;
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70 | /** Pointer to a I/O buffer descriptor. */
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71 | typedef IOBUFDESC *PIOBUFDESC;
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72 |
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73 | /**
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74 | * Creates I/O buffer manager.
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75 | *
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76 | * @returns VBox status code.
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77 | * @param phIoBufMgr Where to store the handle to the I/O buffer manager on success.
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78 | * @param cbMax The maximum amount of I/O memory to allow. Trying to allocate more than
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79 | * this will lead to out of memory errors. 0 for "unlimited" size (only restriction
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80 | * is the available memory on the host).
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81 | * @param fFlags Combination of IOBUFMGR_F_*
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82 | */
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83 | DECLHIDDEN(int) IOBUFMgrCreate(PIOBUFMGR phIoBufMgr, size_t cbMax, uint32_t fFlags);
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84 |
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85 | /**
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86 | * Destroys the given I/O buffer manager.
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87 | *
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88 | * @returns VBox status code.
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89 | * @retval VERR_INVALID_STATE if there is still memory allocated by the given manager.
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90 | * @param hIoBufMgr The I/O buffer manager.
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91 | */
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92 | DECLHIDDEN(int) IOBUFMgrDestroy(IOBUFMGR hIoBufMgr);
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93 |
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94 | /**
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95 | * Allocates a I/O buffer and fills the descriptor.
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96 | *
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97 | * @returns VBox status code.
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98 | * @retval VERR_NO_MEMORY if there is not enough free memory to satisfy the request
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99 | * and partial allocations are not allowed or allocating some internal tracking
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100 | * structures failed.
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101 | * @param hIoBufMgr The I/O buffer manager.
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102 | * @param pIoBufDesc The I/O buffer descriptor to initialize on success.
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103 | * @param cbIoBuf How much to allocate.
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104 | * @param pcbIoBufAllocated Where to store amount of memory the manager was able to allocate
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105 | * if there is not enough free memory to satisfy the complete request.
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106 | * NULL if partial allocations are not supported.
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107 | */
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108 | DECLHIDDEN(int) IOBUFMgrAllocBuf(IOBUFMGR hIoBufMgr, PIOBUFDESC pIoBufDesc, size_t cbIoBuf, size_t *pcbIoBufAllocated);
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109 |
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110 | /**
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111 | * Frees a given I/O buffer.
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112 | *
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113 | * @param pIoBufDesc The I/O buffer descriptor to free.
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114 | */
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115 | DECLHIDDEN(void) IOBUFMgrFreeBuf(PIOBUFDESC pIoBufDesc);
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116 |
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117 | RT_C_DECLS_END
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118 |
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119 | #endif /* !VBOX_INCLUDED_SRC_Storage_IOBufMgmt_h */
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