[e51bd96] | 1 | /* |
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| 2 | * Disk I/O buffering |
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| 3 | * Buffer managment |
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| 4 | * |
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| 5 | * Copyright (C) 2001 OKTET Ltd., St.-Peterburg, Russia |
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| 6 | * Author: Andrey G. Ivanov <Andrey.Ivanov@oktet.ru> |
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| 7 | * Victor V. Vengerov <vvv@oktet.ru> |
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[df6348bb] | 8 | * Alexander Kukuta <kam@oktet.ru> |
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[e51bd96] | 9 | * |
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[c21c850e] | 10 | * Copyright (C) 2008 Chris Johns <chrisj@rtems.org> |
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| 11 | * Rewritten to remove score mutex access. Fixes many performance |
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| 12 | * issues. |
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| 13 | * |
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[3d14a45] | 14 | * @(#) bdbuf.c,v 1.14 2004/04/17 08:15:17 ralf Exp |
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[e51bd96] | 15 | */ |
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| 16 | |
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[3899a537] | 17 | /** |
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| 18 | * @file |
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| 19 | * |
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[c21c850e] | 20 | * The Buffer Descriptor Buffer code implements a cache between the disk |
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| 21 | * devices and file systems. The code provides read ahead and write queuing to |
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| 22 | * the drivers and fast cache look up using an AVL tree. |
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[3899a537] | 23 | * |
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| 24 | * The buffers are held in pools based on size. Each pool has buffers and the |
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| 25 | * buffers follow this state machine: |
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[c21c850e] | 26 | * |
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| 27 | * read/read ahead |
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[3899a537] | 28 | * +-------------------------------+ |
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| 29 | * | v |
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[c21c850e] | 30 | * +-----------+ read ahead +------------+ |
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| 31 | * | READY, | complete | |---------+ |
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| 32 | * | READ |<----------------| TRANSFER | | |
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| 33 | * | AHEAD | +-------------| |<--+ | |
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| 34 | * +-----------+ | read/write +------------+ | | |
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| 35 | * | get v complete swap | | |
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| 36 | * | +-----------+ modified +------------+ | |
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| 37 | * +--->| ACCESSED, |---------->| MODIFIED, | | |
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| 38 | * | ACCESSED |<----------| SYNC | | |
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| 39 | * +----| MODIFIED |<--+ get | | | |
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| 40 | * | +-----------+ | +------------+ | |
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| 41 | * | release get | | |
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| 42 | * | +-----------+ | | |
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| 43 | * +--->| |---+ read complete | |
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| 44 | * | CACHED | write complete | |
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| 45 | * | |<-------------------------+ |
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[3899a537] | 46 | * +-----------+ |
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[c21c850e] | 47 | * |
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| 48 | * Empty buffers are added to the ready list and removed from this queue when a |
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| 49 | * caller requests a buffer. This is referred to as getting a buffer in the |
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| 50 | * code and the event get in the state diagram. The buffer is assigned to a |
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| 51 | * block and inserted to the AVL based on the block/device key. If the block is |
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| 52 | * to be read by the user and not in the cache (ready) it is transfered from |
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| 53 | * the disk into memory. If no ready buffers exist the buffer is taken from the |
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| 54 | * LRU list. If no buffers are on the LRU list the modified list is check. If |
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| 55 | * no buffers are on the modified list the request blocks. If buffers are on |
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| 56 | * the modified list the buffers hold timer is expired and the swap out task |
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| 57 | * woken. |
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[3899a537] | 58 | * |
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[c21c850e] | 59 | * A block being accessed is given to the file system layer and not accessable |
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| 60 | * to another requester until released back to the cache. The same goes to a |
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| 61 | * buffer in the transfer state. The transfer state means being read or |
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| 62 | * written. If the file system has modifed the block and releases it as |
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| 63 | * modified it placed on the pool's modified list and a hold timer |
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| 64 | * initialised. The buffer is held for the hold time before being written to |
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| 65 | * disk. Buffers are held for a configurable period of time on the modified |
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| 66 | * list as a write sets the state to transfer and this locks the buffer out |
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| 67 | * from the file system until the write complete. Buffers are often repeatable |
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| 68 | * accessed and modified in a series of small updates so if sent to the disk |
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| 69 | * when released as modified the user would have to block waiting until it had |
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| 70 | * been written. This would be a performance problem. |
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[3899a537] | 71 | * |
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[c21c850e] | 72 | * The code performs mulitple block reads and writes. Multiple block reads or |
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| 73 | * read ahead increases performance with hardware that supports it. It also |
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| 74 | * helps with a large cache as the disk head movement is reduced. It how-ever |
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| 75 | * is a speculative operation so excessive use can remove valuable and needed |
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| 76 | * blocks from the cache. The get call knows if a read is a for the file system |
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| 77 | * or if it is a read ahead get. If the get is for a read ahead block and the |
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| 78 | * block is already in the cache or no ready buffers are available the read |
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| 79 | * ahead is stopped. The transfer occurs with the blocks so far. If a buffer is |
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| 80 | * in the read ahead state and release it is placed on the ready list rather |
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| 81 | * than the LRU list. This means these buffers are used before buffers used by |
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| 82 | * the file system. |
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[3899a537] | 83 | * |
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[c21c850e] | 84 | * The pool have the following lists of buffers: |
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[3899a537] | 85 | * |
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[c21c850e] | 86 | * ready - Empty buffers created when the pool is initialised. |
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| 87 | * modified - Buffers waiting to be written to disk. |
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| 88 | * sync - Buffers to be synced to disk. |
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| 89 | * lru - Accessed buffers released in least recently used order. |
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[3899a537] | 90 | */ |
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| 91 | |
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| 92 | /** |
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| 93 | * Set to 1 to enable debug tracing. |
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| 94 | */ |
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| 95 | #define RTEMS_BDBUF_TRACE 0 |
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| 96 | |
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[006fa1ef] | 97 | #if HAVE_CONFIG_H |
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| 98 | #include "config.h" |
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| 99 | #endif |
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| 100 | |
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[e51bd96] | 101 | #include <rtems.h> |
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[3899a537] | 102 | #include <rtems/error.h> |
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[e51bd96] | 103 | #include <limits.h> |
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| 104 | #include <errno.h> |
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| 105 | #include <assert.h> |
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| 106 | |
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[3899a537] | 107 | #if RTEMS_BDBUF_TRACE |
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| 108 | #include <stdio.h> |
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[0ebfac19] | 109 | #endif |
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| 110 | |
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[3899a537] | 111 | #include "rtems/bdbuf.h" |
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[e51bd96] | 112 | |
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[3899a537] | 113 | /** |
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| 114 | * The BD buffer context. |
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[0ebfac19] | 115 | */ |
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[3899a537] | 116 | typedef struct rtems_bdbuf_context { |
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[c21c850e] | 117 | rtems_bdbuf_pool* pool; /*< Table of buffer pools */ |
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| 118 | int npools; /*< Number of entries in pool table */ |
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| 119 | rtems_id swapout; /*< Swapout task ID */ |
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[3899a537] | 120 | boolean swapout_enabled; |
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| 121 | } rtems_bdbuf_context; |
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| 122 | |
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| 123 | /** |
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| 124 | * Fatal errors |
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[0ebfac19] | 125 | */ |
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[c21c850e] | 126 | #define RTEMS_BLKDEV_FATAL_ERROR(n) \ |
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| 127 | (((uint32_t)'B' << 24) | ((uint32_t)(n) & (uint32_t)0x00FFFFFF)) |
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[3899a537] | 128 | |
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| 129 | #define RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY RTEMS_BLKDEV_FATAL_ERROR(1) |
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| 130 | #define RTEMS_BLKDEV_FATAL_BDBUF_SWAPOUT RTEMS_BLKDEV_FATAL_ERROR(2) |
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| 131 | #define RTEMS_BLKDEV_FATAL_BDBUF_SYNC_LOCK RTEMS_BLKDEV_FATAL_ERROR(3) |
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| 132 | #define RTEMS_BLKDEV_FATAL_BDBUF_SYNC_UNLOCK RTEMS_BLKDEV_FATAL_ERROR(4) |
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| 133 | #define RTEMS_BLKDEV_FATAL_BDBUF_POOL_LOCK RTEMS_BLKDEV_FATAL_ERROR(5) |
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| 134 | #define RTEMS_BLKDEV_FATAL_BDBUF_POOL_UNLOCK RTEMS_BLKDEV_FATAL_ERROR(6) |
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| 135 | #define RTEMS_BLKDEV_FATAL_BDBUF_POOL_WAIT RTEMS_BLKDEV_FATAL_ERROR(7) |
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| 136 | #define RTEMS_BLKDEV_FATAL_BDBUF_POOL_WAKE RTEMS_BLKDEV_FATAL_ERROR(8) |
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| 137 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE RTEMS_BLKDEV_FATAL_ERROR(9) |
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| 138 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM RTEMS_BLKDEV_FATAL_ERROR(10) |
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| 139 | #define BLKDEV_FATAL_BDBUF_SWAPOUT_RE RTEMS_BLKDEV_FATAL_ERROR(11) |
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| 140 | #define BLKDEV_FATAL_BDBUF_SWAPOUT_TS RTEMS_BLKDEV_FATAL_ERROR(12) |
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| 141 | |
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[c21c850e] | 142 | /** |
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| 143 | * The events used in this code. These should be system events rather than |
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| 144 | * application events. |
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| 145 | */ |
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[3899a537] | 146 | #define RTEMS_BDBUF_TRANSFER_SYNC RTEMS_EVENT_1 |
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| 147 | #define RTEMS_BDBUF_SWAPOUT_SYNC RTEMS_EVENT_2 |
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| 148 | |
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[c21c850e] | 149 | /** |
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| 150 | * The swap out task size. Should be more than enough for most drivers with |
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| 151 | * tracing turned on. |
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| 152 | */ |
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[3899a537] | 153 | #define SWAPOUT_TASK_STACK_SIZE (8 * 1024) |
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| 154 | |
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| 155 | /** |
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| 156 | * Lock semaphore attributes. This is used for locking type mutexes. |
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[c21c850e] | 157 | * |
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| 158 | * @warning Priority inheritance is on. |
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[3899a537] | 159 | */ |
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| 160 | #define RTEMS_BDBUF_POOL_LOCK_ATTRIBS \ |
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| 161 | (RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | \ |
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| 162 | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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[048dcd2b] | 163 | |
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[3899a537] | 164 | /** |
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| 165 | * Waiter semaphore attributes. |
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| 166 | * |
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[c21c850e] | 167 | * @warning Do not configure as inherit priority. If a driver is in the driver |
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| 168 | * initialisation table this locked semaphore will have the IDLE task |
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| 169 | * as the holder and a blocking task will raise the priority of the |
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| 170 | * IDLE task which can cause unsual side effects. |
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[3899a537] | 171 | */ |
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| 172 | #define RTEMS_BDBUF_POOL_WAITER_ATTRIBS \ |
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[c21c850e] | 173 | (RTEMS_PRIORITY | RTEMS_SIMPLE_BINARY_SEMAPHORE | \ |
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[3899a537] | 174 | RTEMS_NO_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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[e51bd96] | 175 | |
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[3899a537] | 176 | /* |
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| 177 | * The swap out task. |
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| 178 | */ |
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| 179 | static rtems_task rtems_bdbuf_swapout_task(rtems_task_argument arg); |
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[048dcd2b] | 180 | |
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[3899a537] | 181 | /** |
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| 182 | * The context of buffering layer. |
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| 183 | */ |
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| 184 | static rtems_bdbuf_context rtems_bdbuf_ctx; |
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[e51bd96] | 185 | |
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[3899a537] | 186 | /** |
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| 187 | * Print a message to the bdbuf trace output and flush it. |
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| 188 | * |
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| 189 | * @param format The format string. See printf for details. |
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| 190 | * @param ... The arguments for the format text. |
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| 191 | * @return int The number of bytes written to the output. |
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| 192 | */ |
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| 193 | #if RTEMS_BDBUF_TRACE |
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| 194 | boolean rtems_bdbuf_tracer; |
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| 195 | static void |
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| 196 | rtems_bdbuf_printf (const char *format, ...) |
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| 197 | { |
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| 198 | va_list args; |
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| 199 | va_start (args, format); |
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| 200 | if (rtems_bdbuf_tracer) |
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| 201 | { |
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| 202 | fprintf (stdout, "bdbuf:"); |
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| 203 | vfprintf (stdout, format, args); |
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| 204 | fflush (stdout); |
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| 205 | } |
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| 206 | } |
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[e51bd96] | 207 | #endif |
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| 208 | |
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[3899a537] | 209 | /** |
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| 210 | * The default maximum height of 32 allows for AVL trees having between |
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| 211 | * 5,704,880 and 4,294,967,295 nodes, depending on order of insertion. You may |
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| 212 | * change this compile-time constant as you wish. |
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| 213 | */ |
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| 214 | #ifndef RTEMS_BDBUF_AVL_MAX_HEIGHT |
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| 215 | #define RTEMS_BDBUF_AVL_MAX_HEIGHT (32) |
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[e51bd96] | 216 | #endif |
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| 217 | |
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[3899a537] | 218 | /** |
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| 219 | * Searches for the node with specified dev/block. |
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[e51bd96] | 220 | * |
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[3899a537] | 221 | * @param root pointer to the root node of the AVL-Tree |
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| 222 | * @param dev device search key |
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| 223 | * @param block block search key |
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| 224 | * @retval NULL node with the specified dev/block is not found |
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| 225 | * @return pointer to the node with specified dev/block |
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[e51bd96] | 226 | */ |
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[3899a537] | 227 | static rtems_bdbuf_buffer * |
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| 228 | rtems_bdbuf_avl_search (rtems_bdbuf_buffer** root, |
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| 229 | dev_t dev, |
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| 230 | rtems_blkdev_bnum block) |
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[e51bd96] | 231 | { |
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[3899a537] | 232 | rtems_bdbuf_buffer* p = *root; |
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[df6348bb] | 233 | |
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[3899a537] | 234 | while ((p != NULL) && ((p->dev != dev) || (p->block != block))) |
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| 235 | { |
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| 236 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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[e51bd96] | 237 | { |
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[3899a537] | 238 | p = p->avl.right; |
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| 239 | } |
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| 240 | else |
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| 241 | { |
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| 242 | p = p->avl.left; |
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[e51bd96] | 243 | } |
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[3899a537] | 244 | } |
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[048dcd2b] | 245 | |
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[3899a537] | 246 | return p; |
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[e51bd96] | 247 | } |
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| 248 | |
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[3899a537] | 249 | /** |
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| 250 | * Inserts the specified node to the AVl-Tree. |
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[e51bd96] | 251 | * |
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[3899a537] | 252 | * @param root pointer to the root node of the AVL-Tree |
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| 253 | * @param node Pointer to the node to add. |
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| 254 | * @retval 0 The node added successfully |
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| 255 | * @retval -1 An error occured |
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[e51bd96] | 256 | */ |
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| 257 | static int |
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[3899a537] | 258 | rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root, |
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| 259 | rtems_bdbuf_buffer* node) |
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[e51bd96] | 260 | { |
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[3899a537] | 261 | dev_t dev = node->dev; |
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| 262 | rtems_blkdev_bnum block = node->block; |
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| 263 | |
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| 264 | rtems_bdbuf_buffer* p = *root; |
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| 265 | rtems_bdbuf_buffer* q; |
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| 266 | rtems_bdbuf_buffer* p1; |
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| 267 | rtems_bdbuf_buffer* p2; |
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| 268 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
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| 269 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
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| 270 | |
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| 271 | boolean modified = FALSE; |
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| 272 | |
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| 273 | if (p == NULL) |
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| 274 | { |
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| 275 | *root = node; |
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| 276 | node->avl.left = NULL; |
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| 277 | node->avl.right = NULL; |
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| 278 | node->avl.bal = 0; |
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| 279 | return 0; |
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| 280 | } |
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[e51bd96] | 281 | |
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[3899a537] | 282 | while (p != NULL) |
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| 283 | { |
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| 284 | *buf_prev++ = p; |
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[e51bd96] | 285 | |
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[3899a537] | 286 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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[e51bd96] | 287 | { |
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[3899a537] | 288 | p->avl.cache = 1; |
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| 289 | q = p->avl.right; |
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| 290 | if (q == NULL) |
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| 291 | { |
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| 292 | q = node; |
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| 293 | p->avl.right = q = node; |
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| 294 | break; |
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| 295 | } |
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[e51bd96] | 296 | } |
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[3899a537] | 297 | else if ((p->dev != dev) || (p->block != block)) |
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[e51bd96] | 298 | { |
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[3899a537] | 299 | p->avl.cache = -1; |
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| 300 | q = p->avl.left; |
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| 301 | if (q == NULL) |
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| 302 | { |
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| 303 | q = node; |
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| 304 | p->avl.left = q; |
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| 305 | break; |
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| 306 | } |
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| 307 | } |
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| 308 | else |
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| 309 | { |
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| 310 | return -1; |
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[e51bd96] | 311 | } |
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| 312 | |
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[3899a537] | 313 | p = q; |
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| 314 | } |
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[e51bd96] | 315 | |
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[3899a537] | 316 | q->avl.left = q->avl.right = NULL; |
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| 317 | q->avl.bal = 0; |
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| 318 | modified = TRUE; |
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| 319 | buf_prev--; |
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[e51bd96] | 320 | |
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[3899a537] | 321 | while (modified) |
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| 322 | { |
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| 323 | if (p->avl.cache == -1) |
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| 324 | { |
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| 325 | switch (p->avl.bal) |
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| 326 | { |
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| 327 | case 1: |
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| 328 | p->avl.bal = 0; |
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| 329 | modified = FALSE; |
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| 330 | break; |
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| 331 | |
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| 332 | case 0: |
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| 333 | p->avl.bal = -1; |
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| 334 | break; |
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| 335 | |
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| 336 | case -1: |
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| 337 | p1 = p->avl.left; |
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| 338 | if (p1->avl.bal == -1) /* simple LL-turn */ |
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| 339 | { |
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| 340 | p->avl.left = p1->avl.right; |
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| 341 | p1->avl.right = p; |
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| 342 | p->avl.bal = 0; |
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| 343 | p = p1; |
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| 344 | } |
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| 345 | else /* double LR-turn */ |
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| 346 | { |
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| 347 | p2 = p1->avl.right; |
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| 348 | p1->avl.right = p2->avl.left; |
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| 349 | p2->avl.left = p1; |
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| 350 | p->avl.left = p2->avl.right; |
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| 351 | p2->avl.right = p; |
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| 352 | if (p2->avl.bal == -1) p->avl.bal = +1; else p->avl.bal = 0; |
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| 353 | if (p2->avl.bal == +1) p1->avl.bal = -1; else p1->avl.bal = 0; |
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| 354 | p = p2; |
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| 355 | } |
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| 356 | p->avl.bal = 0; |
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| 357 | modified = FALSE; |
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| 358 | break; |
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| 359 | |
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| 360 | default: |
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| 361 | break; |
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| 362 | } |
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| 363 | } |
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| 364 | else |
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| 365 | { |
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| 366 | switch (p->avl.bal) |
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| 367 | { |
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| 368 | case -1: |
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| 369 | p->avl.bal = 0; |
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| 370 | modified = FALSE; |
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| 371 | break; |
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| 372 | |
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| 373 | case 0: |
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| 374 | p->avl.bal = 1; |
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| 375 | break; |
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| 376 | |
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| 377 | case 1: |
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| 378 | p1 = p->avl.right; |
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| 379 | if (p1->avl.bal == 1) /* simple RR-turn */ |
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| 380 | { |
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| 381 | p->avl.right = p1->avl.left; |
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| 382 | p1->avl.left = p; |
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| 383 | p->avl.bal = 0; |
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| 384 | p = p1; |
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| 385 | } |
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| 386 | else /* double RL-turn */ |
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| 387 | { |
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| 388 | p2 = p1->avl.left; |
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| 389 | p1->avl.left = p2->avl.right; |
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| 390 | p2->avl.right = p1; |
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| 391 | p->avl.right = p2->avl.left; |
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| 392 | p2->avl.left = p; |
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| 393 | if (p2->avl.bal == +1) p->avl.bal = -1; else p->avl.bal = 0; |
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| 394 | if (p2->avl.bal == -1) p1->avl.bal = +1; else p1->avl.bal = 0; |
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| 395 | p = p2; |
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| 396 | } |
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| 397 | p->avl.bal = 0; |
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| 398 | modified = FALSE; |
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| 399 | break; |
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| 400 | |
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| 401 | default: |
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| 402 | break; |
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| 403 | } |
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| 404 | } |
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| 405 | q = p; |
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| 406 | if (buf_prev > buf_stack) |
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| 407 | { |
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| 408 | p = *--buf_prev; |
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| 409 | |
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| 410 | if (p->avl.cache == -1) |
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| 411 | { |
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| 412 | p->avl.left = q; |
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| 413 | } |
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| 414 | else |
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| 415 | { |
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| 416 | p->avl.right = q; |
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| 417 | } |
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| 418 | } |
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| 419 | else |
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| 420 | { |
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| 421 | *root = p; |
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| 422 | break; |
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| 423 | } |
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| 424 | }; |
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[e51bd96] | 425 | |
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[3899a537] | 426 | return 0; |
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[e51bd96] | 427 | } |
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| 428 | |
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| 429 | |
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[3899a537] | 430 | /** |
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| 431 | * Removes the node from the tree. |
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[e51bd96] | 432 | * |
---|
[3899a537] | 433 | * @param root_addr Pointer to pointer to the root node |
---|
| 434 | * @param node Pointer to the node to remove |
---|
| 435 | * @retval 0 Item removed |
---|
| 436 | * @retval -1 No such item found |
---|
[e51bd96] | 437 | */ |
---|
| 438 | static int |
---|
[3899a537] | 439 | rtems_bdbuf_avl_remove(rtems_bdbuf_buffer** root, |
---|
| 440 | const rtems_bdbuf_buffer* node) |
---|
[e51bd96] | 441 | { |
---|
[3899a537] | 442 | dev_t dev = node->dev; |
---|
| 443 | rtems_blkdev_bnum block = node->block; |
---|
[e51bd96] | 444 | |
---|
[3899a537] | 445 | rtems_bdbuf_buffer* p = *root; |
---|
| 446 | rtems_bdbuf_buffer* q; |
---|
| 447 | rtems_bdbuf_buffer* r; |
---|
| 448 | rtems_bdbuf_buffer* s; |
---|
| 449 | rtems_bdbuf_buffer* p1; |
---|
| 450 | rtems_bdbuf_buffer* p2; |
---|
| 451 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
---|
| 452 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
---|
[e51bd96] | 453 | |
---|
[3899a537] | 454 | boolean modified = FALSE; |
---|
[e51bd96] | 455 | |
---|
[3899a537] | 456 | memset (buf_stack, 0, sizeof(buf_stack)); |
---|
[e51bd96] | 457 | |
---|
[3899a537] | 458 | while (p != NULL) |
---|
| 459 | { |
---|
| 460 | *buf_prev++ = p; |
---|
[e51bd96] | 461 | |
---|
[3899a537] | 462 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
---|
| 463 | { |
---|
| 464 | p->avl.cache = 1; |
---|
| 465 | p = p->avl.right; |
---|
| 466 | } |
---|
| 467 | else if ((p->dev != dev) || (p->block != block)) |
---|
| 468 | { |
---|
| 469 | p->avl.cache = -1; |
---|
| 470 | p = p->avl.left; |
---|
[df6348bb] | 471 | } |
---|
[3899a537] | 472 | else |
---|
| 473 | { |
---|
| 474 | /* node found */ |
---|
| 475 | break; |
---|
| 476 | } |
---|
| 477 | } |
---|
| 478 | |
---|
| 479 | if (p == NULL) |
---|
| 480 | { |
---|
| 481 | /* there is no such node */ |
---|
| 482 | return -1; |
---|
| 483 | } |
---|
[048dcd2b] | 484 | |
---|
[3899a537] | 485 | q = p; |
---|
| 486 | |
---|
| 487 | buf_prev--; |
---|
| 488 | if (buf_prev > buf_stack) |
---|
| 489 | { |
---|
| 490 | p = *(buf_prev - 1); |
---|
| 491 | } |
---|
| 492 | else |
---|
| 493 | { |
---|
| 494 | p = NULL; |
---|
| 495 | } |
---|
| 496 | |
---|
| 497 | /* at this moment q - is a node to delete, p is q's parent */ |
---|
| 498 | if (q->avl.right == NULL) |
---|
| 499 | { |
---|
| 500 | r = q->avl.left; |
---|
| 501 | if (r != NULL) |
---|
[df6348bb] | 502 | { |
---|
[3899a537] | 503 | r->avl.bal = 0; |
---|
[e51bd96] | 504 | } |
---|
[3899a537] | 505 | q = r; |
---|
| 506 | } |
---|
| 507 | else |
---|
| 508 | { |
---|
| 509 | rtems_bdbuf_buffer **t; |
---|
[e51bd96] | 510 | |
---|
[3899a537] | 511 | r = q->avl.right; |
---|
[df6348bb] | 512 | |
---|
[3899a537] | 513 | if (r->avl.left == NULL) |
---|
[e51bd96] | 514 | { |
---|
[3899a537] | 515 | r->avl.left = q->avl.left; |
---|
| 516 | r->avl.bal = q->avl.bal; |
---|
| 517 | r->avl.cache = 1; |
---|
| 518 | *buf_prev++ = q = r; |
---|
[e51bd96] | 519 | } |
---|
| 520 | else |
---|
| 521 | { |
---|
[3899a537] | 522 | t = buf_prev++; |
---|
| 523 | s = r; |
---|
| 524 | |
---|
| 525 | while (s->avl.left != NULL) |
---|
| 526 | { |
---|
| 527 | *buf_prev++ = r = s; |
---|
| 528 | s = r->avl.left; |
---|
| 529 | r->avl.cache = -1; |
---|
| 530 | } |
---|
| 531 | |
---|
| 532 | s->avl.left = q->avl.left; |
---|
| 533 | r->avl.left = s->avl.right; |
---|
| 534 | s->avl.right = q->avl.right; |
---|
| 535 | s->avl.bal = q->avl.bal; |
---|
| 536 | s->avl.cache = 1; |
---|
| 537 | |
---|
| 538 | *t = q = s; |
---|
[e51bd96] | 539 | } |
---|
[3899a537] | 540 | } |
---|
[df6348bb] | 541 | |
---|
[3899a537] | 542 | if (p != NULL) |
---|
| 543 | { |
---|
| 544 | if (p->avl.cache == -1) |
---|
[e51bd96] | 545 | { |
---|
[3899a537] | 546 | p->avl.left = q; |
---|
[e51bd96] | 547 | } |
---|
| 548 | else |
---|
| 549 | { |
---|
[3899a537] | 550 | p->avl.right = q; |
---|
[e51bd96] | 551 | } |
---|
[3899a537] | 552 | } |
---|
| 553 | else |
---|
| 554 | { |
---|
| 555 | *root = q; |
---|
| 556 | } |
---|
[e51bd96] | 557 | |
---|
[3899a537] | 558 | modified = TRUE; |
---|
| 559 | |
---|
| 560 | while (modified) |
---|
| 561 | { |
---|
| 562 | if (buf_prev > buf_stack) |
---|
[e51bd96] | 563 | { |
---|
[3899a537] | 564 | p = *--buf_prev; |
---|
[df6348bb] | 565 | } |
---|
| 566 | else |
---|
| 567 | { |
---|
[3899a537] | 568 | break; |
---|
[df6348bb] | 569 | } |
---|
[e51bd96] | 570 | |
---|
[3899a537] | 571 | if (p->avl.cache == -1) |
---|
[df6348bb] | 572 | { |
---|
[3899a537] | 573 | /* rebalance left branch */ |
---|
| 574 | switch (p->avl.bal) |
---|
| 575 | { |
---|
| 576 | case -1: |
---|
| 577 | p->avl.bal = 0; |
---|
| 578 | break; |
---|
| 579 | case 0: |
---|
| 580 | p->avl.bal = 1; |
---|
| 581 | modified = FALSE; |
---|
| 582 | break; |
---|
| 583 | |
---|
| 584 | case +1: |
---|
| 585 | p1 = p->avl.right; |
---|
| 586 | |
---|
| 587 | if (p1->avl.bal >= 0) /* simple RR-turn */ |
---|
| 588 | { |
---|
| 589 | p->avl.right = p1->avl.left; |
---|
| 590 | p1->avl.left = p; |
---|
| 591 | |
---|
| 592 | if (p1->avl.bal == 0) |
---|
[e51bd96] | 593 | { |
---|
[3899a537] | 594 | p1->avl.bal = -1; |
---|
| 595 | modified = FALSE; |
---|
[df6348bb] | 596 | } |
---|
[3899a537] | 597 | else |
---|
[e51bd96] | 598 | { |
---|
[3899a537] | 599 | p->avl.bal = 0; |
---|
| 600 | p1->avl.bal = 0; |
---|
[df6348bb] | 601 | } |
---|
[3899a537] | 602 | p = p1; |
---|
| 603 | } |
---|
| 604 | else /* double RL-turn */ |
---|
| 605 | { |
---|
| 606 | p2 = p1->avl.left; |
---|
| 607 | |
---|
| 608 | p1->avl.left = p2->avl.right; |
---|
| 609 | p2->avl.right = p1; |
---|
| 610 | p->avl.right = p2->avl.left; |
---|
| 611 | p2->avl.left = p; |
---|
| 612 | |
---|
| 613 | if (p2->avl.bal == +1) p->avl.bal = -1; else p->avl.bal = 0; |
---|
| 614 | if (p2->avl.bal == -1) p1->avl.bal = 1; else p1->avl.bal = 0; |
---|
| 615 | |
---|
| 616 | p = p2; |
---|
| 617 | p2->avl.bal = 0; |
---|
| 618 | } |
---|
| 619 | break; |
---|
| 620 | |
---|
| 621 | default: |
---|
| 622 | break; |
---|
| 623 | } |
---|
| 624 | } |
---|
| 625 | else |
---|
| 626 | { |
---|
| 627 | /* rebalance right branch */ |
---|
| 628 | switch (p->avl.bal) |
---|
| 629 | { |
---|
| 630 | case +1: |
---|
| 631 | p->avl.bal = 0; |
---|
| 632 | break; |
---|
| 633 | |
---|
| 634 | case 0: |
---|
| 635 | p->avl.bal = -1; |
---|
| 636 | modified = FALSE; |
---|
| 637 | break; |
---|
| 638 | |
---|
| 639 | case -1: |
---|
| 640 | p1 = p->avl.left; |
---|
| 641 | |
---|
| 642 | if (p1->avl.bal <= 0) /* simple LL-turn */ |
---|
| 643 | { |
---|
| 644 | p->avl.left = p1->avl.right; |
---|
| 645 | p1->avl.right = p; |
---|
| 646 | if (p1->avl.bal == 0) |
---|
[df6348bb] | 647 | { |
---|
[3899a537] | 648 | p1->avl.bal = 1; |
---|
| 649 | modified = FALSE; |
---|
[df6348bb] | 650 | } |
---|
| 651 | else |
---|
| 652 | { |
---|
[3899a537] | 653 | p->avl.bal = 0; |
---|
| 654 | p1->avl.bal = 0; |
---|
[df6348bb] | 655 | } |
---|
[3899a537] | 656 | p = p1; |
---|
| 657 | } |
---|
| 658 | else /* double LR-turn */ |
---|
| 659 | { |
---|
| 660 | p2 = p1->avl.right; |
---|
| 661 | |
---|
| 662 | p1->avl.right = p2->avl.left; |
---|
| 663 | p2->avl.left = p1; |
---|
| 664 | p->avl.left = p2->avl.right; |
---|
| 665 | p2->avl.right = p; |
---|
| 666 | |
---|
| 667 | if (p2->avl.bal == -1) p->avl.bal = 1; else p->avl.bal = 0; |
---|
| 668 | if (p2->avl.bal == +1) p1->avl.bal = -1; else p1->avl.bal = 0; |
---|
| 669 | |
---|
| 670 | p = p2; |
---|
| 671 | p2->avl.bal = 0; |
---|
| 672 | } |
---|
| 673 | break; |
---|
| 674 | |
---|
| 675 | default: |
---|
| 676 | break; |
---|
| 677 | } |
---|
| 678 | } |
---|
[df6348bb] | 679 | |
---|
[3899a537] | 680 | if (buf_prev > buf_stack) |
---|
| 681 | { |
---|
| 682 | q = *(buf_prev - 1); |
---|
| 683 | |
---|
| 684 | if (q->avl.cache == -1) |
---|
| 685 | { |
---|
| 686 | q->avl.left = p; |
---|
| 687 | } |
---|
| 688 | else |
---|
| 689 | { |
---|
| 690 | q->avl.right = p; |
---|
| 691 | } |
---|
| 692 | } |
---|
| 693 | else |
---|
| 694 | { |
---|
| 695 | *root = p; |
---|
| 696 | break; |
---|
[df6348bb] | 697 | } |
---|
[048dcd2b] | 698 | |
---|
[3899a537] | 699 | } |
---|
| 700 | |
---|
| 701 | return 0; |
---|
| 702 | } |
---|
| 703 | |
---|
| 704 | /** |
---|
| 705 | * Get the pool for the device. |
---|
| 706 | * |
---|
| 707 | * @param pdd Physical disk device. |
---|
| 708 | */ |
---|
| 709 | static rtems_bdbuf_pool* |
---|
| 710 | rtems_bdbuf_get_pool (const rtems_bdpool_id pid) |
---|
| 711 | { |
---|
| 712 | return &rtems_bdbuf_ctx.pool[pid]; |
---|
| 713 | } |
---|
| 714 | |
---|
| 715 | /** |
---|
| 716 | * Lock the pool. A single task can nest calls. |
---|
| 717 | * |
---|
| 718 | * @param pool The pool to lock. |
---|
| 719 | */ |
---|
| 720 | static void |
---|
| 721 | rtems_bdbuf_lock_pool (rtems_bdbuf_pool* pool) |
---|
| 722 | { |
---|
| 723 | rtems_status_code sc = rtems_semaphore_obtain (pool->lock, |
---|
| 724 | RTEMS_WAIT, |
---|
| 725 | RTEMS_NO_TIMEOUT); |
---|
| 726 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 727 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_POOL_LOCK); |
---|
| 728 | } |
---|
| 729 | |
---|
| 730 | /** |
---|
| 731 | * Unlock the pool. |
---|
| 732 | * |
---|
| 733 | * @param pool The pool to unlock. |
---|
| 734 | */ |
---|
| 735 | static void |
---|
| 736 | rtems_bdbuf_unlock_pool (rtems_bdbuf_pool* pool) |
---|
| 737 | { |
---|
| 738 | rtems_status_code sc = rtems_semaphore_release (pool->lock); |
---|
| 739 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 740 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_POOL_UNLOCK); |
---|
| 741 | } |
---|
| 742 | |
---|
| 743 | /** |
---|
| 744 | * Lock the pool's sync. A single task can nest calls. |
---|
| 745 | * |
---|
| 746 | * @param pool The pool's sync to lock. |
---|
| 747 | */ |
---|
| 748 | static void |
---|
| 749 | rtems_bdbuf_lock_sync (rtems_bdbuf_pool* pool) |
---|
| 750 | { |
---|
| 751 | rtems_status_code sc = rtems_semaphore_obtain (pool->sync_lock, |
---|
| 752 | RTEMS_WAIT, |
---|
| 753 | RTEMS_NO_TIMEOUT); |
---|
| 754 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 755 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SYNC_LOCK); |
---|
| 756 | } |
---|
| 757 | |
---|
| 758 | /** |
---|
| 759 | * Unlock the pool's sync. |
---|
| 760 | * |
---|
| 761 | * @param pool The pool's sync to unlock. |
---|
| 762 | */ |
---|
| 763 | static void |
---|
| 764 | rtems_bdbuf_unlock_sync (rtems_bdbuf_pool* pool) |
---|
| 765 | { |
---|
| 766 | rtems_status_code sc = rtems_semaphore_release (pool->sync_lock); |
---|
| 767 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 768 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SYNC_UNLOCK); |
---|
| 769 | } |
---|
| 770 | |
---|
| 771 | /** |
---|
[c21c850e] | 772 | * Wait until woken. Semaphores are used so a number of tasks can wait and can |
---|
| 773 | * be woken at once. Task events would require we maintain a list of tasks to |
---|
| 774 | * be woken and this would require storgage and we do not know the number of |
---|
| 775 | * tasks that could be waiting. |
---|
[3899a537] | 776 | * |
---|
| 777 | * While we have the pool locked we can try and claim the semaphore and |
---|
| 778 | * therefore know when we release the lock to the pool we will block until the |
---|
| 779 | * semaphore is released. This may even happen before we get to block. |
---|
| 780 | * |
---|
| 781 | * A counter is used to save the release call when no one is waiting. |
---|
| 782 | * |
---|
[c21c850e] | 783 | * The function assumes the pool is locked on entry and it will be locked on |
---|
| 784 | * exit. |
---|
[3899a537] | 785 | * |
---|
| 786 | * @param pool The pool to wait for a buffer to return. |
---|
| 787 | * @param sema The semaphore to block on and wait. |
---|
| 788 | * @param waiters The wait counter for this semaphore. |
---|
| 789 | */ |
---|
| 790 | static void |
---|
| 791 | rtems_bdbuf_wait (rtems_bdbuf_pool* pool, rtems_id* sema, |
---|
| 792 | volatile uint32_t* waiters) |
---|
| 793 | { |
---|
| 794 | rtems_status_code sc; |
---|
| 795 | rtems_mode prev_mode; |
---|
| 796 | |
---|
| 797 | /* |
---|
| 798 | * Indicate we are waiting. |
---|
| 799 | */ |
---|
| 800 | *waiters += 1; |
---|
| 801 | |
---|
| 802 | /* |
---|
| 803 | * Disable preemption then unlock the pool and block. |
---|
| 804 | * There is no POSIX condition variable in the core API so |
---|
| 805 | * this is a work around. |
---|
| 806 | * |
---|
| 807 | * The issue is a task could preempt after the pool is unlocked |
---|
| 808 | * because it is blocking or just hits that window, and before |
---|
| 809 | * this task has blocked on the semaphore. If the preempting task |
---|
| 810 | * flushes the queue this task will not see the flush and may |
---|
| 811 | * block for ever or until another transaction flushes this |
---|
| 812 | * semaphore. |
---|
| 813 | */ |
---|
| 814 | sc = rtems_task_mode (RTEMS_NO_PREEMPT, RTEMS_PREEMPT_MASK, &prev_mode); |
---|
| 815 | |
---|
| 816 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 817 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_POOL_WAIT); |
---|
| 818 | |
---|
| 819 | /* |
---|
| 820 | * Unlock the pool, wait, and lock the pool when we return. |
---|
| 821 | */ |
---|
| 822 | rtems_bdbuf_unlock_pool (pool); |
---|
| 823 | |
---|
| 824 | sc = rtems_semaphore_obtain (*sema, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
---|
| 825 | |
---|
| 826 | if (sc != RTEMS_UNSATISFIED) |
---|
| 827 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_POOL_WAIT); |
---|
| 828 | |
---|
| 829 | rtems_bdbuf_lock_pool (pool); |
---|
| 830 | |
---|
| 831 | sc = rtems_task_mode (prev_mode, RTEMS_ALL_MODE_MASKS, &prev_mode); |
---|
| 832 | |
---|
| 833 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 834 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_POOL_WAIT); |
---|
| 835 | |
---|
| 836 | *waiters -= 1; |
---|
| 837 | } |
---|
| 838 | |
---|
| 839 | /** |
---|
| 840 | * Wake a blocked resource. The resource has a counter that lets us know if |
---|
| 841 | * there are any waiters. |
---|
| 842 | * |
---|
| 843 | * @param sema The semaphore to release. |
---|
| 844 | * @param waiters The wait counter for this semaphore. |
---|
| 845 | */ |
---|
| 846 | static void |
---|
| 847 | rtems_bdbuf_wake (rtems_id sema, volatile uint32_t* waiters) |
---|
| 848 | { |
---|
| 849 | if (*waiters) |
---|
| 850 | { |
---|
| 851 | rtems_status_code sc; |
---|
| 852 | |
---|
| 853 | sc = rtems_semaphore_flush (sema); |
---|
| 854 | |
---|
| 855 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 856 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_POOL_WAKE); |
---|
| 857 | } |
---|
| 858 | } |
---|
| 859 | |
---|
| 860 | /** |
---|
| 861 | * Add a buffer descriptor to the modified list. This modified list is treated |
---|
| 862 | * a litte differently to the other lists. To access it you must have the pool |
---|
[c21c850e] | 863 | * locked and this is assumed to be the case on entry to this call. |
---|
| 864 | * |
---|
| 865 | * If the pool has a device being sync'ed and the bd is for that device the |
---|
| 866 | * call must block and wait until the sync is over before adding the bd to the |
---|
| 867 | * modified list. Once a sync happens for a device no bd's can be added the |
---|
| 868 | * modified list. The disk image is forced to be snapshot at that moment in |
---|
| 869 | * time. |
---|
| 870 | * |
---|
| 871 | * and you must |
---|
[3899a537] | 872 | * hold the sync lock. The sync lock is used to block writes while a sync is |
---|
| 873 | * active. |
---|
| 874 | * |
---|
[c21c850e] | 875 | * @param pool The pool the bd belongs to. |
---|
| 876 | * @param bd The bd to queue to the pool's modified list. |
---|
[3899a537] | 877 | */ |
---|
| 878 | static void |
---|
| 879 | rtems_bdbuf_append_modified (rtems_bdbuf_pool* pool, rtems_bdbuf_buffer* bd) |
---|
| 880 | { |
---|
| 881 | /* |
---|
[c21c850e] | 882 | * If the pool has a device being sync'ed check if this bd is for that |
---|
| 883 | * device. If it is unlock the pool and block on the sync lock. once we have |
---|
| 884 | * the sync lock reelase it. |
---|
| 885 | * |
---|
| 886 | * If the |
---|
[3899a537] | 887 | */ |
---|
[c21c850e] | 888 | if (pool->sync_active && (pool->sync_device == bd->dev)) |
---|
[3899a537] | 889 | { |
---|
| 890 | rtems_bdbuf_unlock_pool (pool); |
---|
| 891 | rtems_bdbuf_lock_sync (pool); |
---|
[c21c850e] | 892 | rtems_bdbuf_unlock_sync (pool); |
---|
[3899a537] | 893 | rtems_bdbuf_lock_pool (pool); |
---|
| 894 | } |
---|
| 895 | |
---|
| 896 | bd->state = RTEMS_BDBUF_STATE_MODIFIED; |
---|
| 897 | |
---|
| 898 | rtems_chain_append (&pool->modified, &bd->link); |
---|
| 899 | } |
---|
| 900 | |
---|
[c21c850e] | 901 | /** |
---|
| 902 | * Wait the swapper task. |
---|
| 903 | */ |
---|
[3899a537] | 904 | static void |
---|
[a5fb40cf] | 905 | rtems_bdbuf_wake_swapper (void) |
---|
[3899a537] | 906 | { |
---|
| 907 | rtems_status_code sc = rtems_event_send (rtems_bdbuf_ctx.swapout, |
---|
| 908 | RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
| 909 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 910 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE); |
---|
[e51bd96] | 911 | } |
---|
| 912 | |
---|
[c21c850e] | 913 | /** |
---|
| 914 | * Initialize single buffer pool. |
---|
[e51bd96] | 915 | * |
---|
[c21c850e] | 916 | * @param config Buffer pool configuration |
---|
| 917 | * @param pid Pool number |
---|
[e51bd96] | 918 | * |
---|
[c21c850e] | 919 | * @return RTEMS_SUCCESSFUL, if buffer pool initialized successfully, or error |
---|
| 920 | * code if error occured. |
---|
[e51bd96] | 921 | */ |
---|
| 922 | static rtems_status_code |
---|
[3899a537] | 923 | rtems_bdbuf_initialize_pool (rtems_bdbuf_pool_config* config, |
---|
| 924 | rtems_bdpool_id pid) |
---|
[e51bd96] | 925 | { |
---|
[3899a537] | 926 | unsigned char* buffer = config->mem_area; |
---|
| 927 | rtems_bdbuf_pool* pool; |
---|
| 928 | rtems_bdbuf_buffer* bd; |
---|
| 929 | rtems_status_code sc; |
---|
| 930 | int b; |
---|
[048dcd2b] | 931 | |
---|
[3899a537] | 932 | pool = rtems_bdbuf_get_pool (pid); |
---|
| 933 | |
---|
[c21c850e] | 934 | pool->blksize = config->size; |
---|
| 935 | pool->nblks = config->num; |
---|
| 936 | pool->flags = 0; |
---|
| 937 | pool->sync_active = FALSE; |
---|
| 938 | pool->sync_device = -1; |
---|
| 939 | pool->sync_requester = 0; |
---|
| 940 | pool->tree = NULL; |
---|
| 941 | pool->buffers = NULL; |
---|
[3899a537] | 942 | |
---|
| 943 | rtems_chain_initialize_empty (&pool->ready); |
---|
| 944 | rtems_chain_initialize_empty (&pool->lru); |
---|
| 945 | rtems_chain_initialize_empty (&pool->modified); |
---|
| 946 | rtems_chain_initialize_empty (&pool->sync); |
---|
| 947 | |
---|
[c21c850e] | 948 | pool->access = 0; |
---|
| 949 | pool->access_waiters = 0; |
---|
| 950 | pool->transfer = 0; |
---|
[3899a537] | 951 | pool->transfer_waiters = 0; |
---|
[c21c850e] | 952 | pool->waiting = 0; |
---|
| 953 | pool->wait_waiters = 0; |
---|
[3899a537] | 954 | |
---|
| 955 | /* |
---|
| 956 | * Allocate memory for buffer descriptors |
---|
| 957 | */ |
---|
| 958 | pool->bds = calloc (config->num, sizeof (rtems_bdbuf_buffer)); |
---|
| 959 | |
---|
| 960 | if (!pool->bds) |
---|
| 961 | return RTEMS_NO_MEMORY; |
---|
| 962 | |
---|
| 963 | /* |
---|
| 964 | * Allocate memory for buffers if required. |
---|
| 965 | */ |
---|
| 966 | if (buffer == NULL) |
---|
| 967 | { |
---|
| 968 | buffer = pool->buffers = malloc (config->num * config->size); |
---|
| 969 | if (!pool->buffers) |
---|
[e51bd96] | 970 | { |
---|
[3899a537] | 971 | free (pool->bds); |
---|
| 972 | return RTEMS_NO_MEMORY; |
---|
[e51bd96] | 973 | } |
---|
[3899a537] | 974 | } |
---|
[048dcd2b] | 975 | |
---|
[3899a537] | 976 | for (b = 0, bd = pool->bds; |
---|
| 977 | b < pool->nblks; |
---|
| 978 | b++, bd++, buffer += pool->blksize) |
---|
| 979 | { |
---|
| 980 | bd->dev = -1; |
---|
| 981 | bd->block = 0; |
---|
| 982 | bd->buffer = buffer; |
---|
| 983 | bd->avl.left = NULL; |
---|
| 984 | bd->avl.right = NULL; |
---|
| 985 | bd->state = RTEMS_BDBUF_STATE_EMPTY; |
---|
| 986 | bd->pool = pid; |
---|
| 987 | bd->error = 0; |
---|
| 988 | bd->waiters = 0; |
---|
| 989 | bd->hold_timer = 0; |
---|
| 990 | |
---|
| 991 | rtems_chain_append (&pool->ready, &bd->link); |
---|
| 992 | } |
---|
[048dcd2b] | 993 | |
---|
[3899a537] | 994 | sc = rtems_semaphore_create (rtems_build_name ('B', 'P', '0' + pid, 'L'), |
---|
| 995 | 1, RTEMS_BDBUF_POOL_LOCK_ATTRIBS, 0, |
---|
| 996 | &pool->lock); |
---|
| 997 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 998 | { |
---|
| 999 | free (pool->buffers); |
---|
| 1000 | free (pool->bds); |
---|
| 1001 | return sc; |
---|
| 1002 | } |
---|
[048dcd2b] | 1003 | |
---|
[c21c850e] | 1004 | sc = rtems_semaphore_create (rtems_build_name ('B', 'P', '0' + pid, 'S'), |
---|
| 1005 | 1, RTEMS_BDBUF_POOL_LOCK_ATTRIBS, 0, |
---|
[3899a537] | 1006 | &pool->sync_lock); |
---|
| 1007 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1008 | { |
---|
| 1009 | rtems_semaphore_delete (pool->lock); |
---|
| 1010 | free (pool->buffers); |
---|
| 1011 | free (pool->bds); |
---|
| 1012 | return sc; |
---|
| 1013 | } |
---|
| 1014 | |
---|
| 1015 | sc = rtems_semaphore_create (rtems_build_name ('B', 'P', '0' + pid, 'a'), |
---|
| 1016 | 0, RTEMS_BDBUF_POOL_WAITER_ATTRIBS, 0, |
---|
| 1017 | &pool->access); |
---|
| 1018 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1019 | { |
---|
| 1020 | rtems_semaphore_delete (pool->sync_lock); |
---|
| 1021 | rtems_semaphore_delete (pool->lock); |
---|
| 1022 | free (pool->buffers); |
---|
| 1023 | free (pool->bds); |
---|
| 1024 | return sc; |
---|
| 1025 | } |
---|
[048dcd2b] | 1026 | |
---|
[3899a537] | 1027 | sc = rtems_semaphore_create (rtems_build_name ('B', 'P', '0' + pid, 't'), |
---|
| 1028 | 0, RTEMS_BDBUF_POOL_WAITER_ATTRIBS, 0, |
---|
| 1029 | &pool->transfer); |
---|
| 1030 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1031 | { |
---|
| 1032 | rtems_semaphore_delete (pool->access); |
---|
| 1033 | rtems_semaphore_delete (pool->sync_lock); |
---|
| 1034 | rtems_semaphore_delete (pool->lock); |
---|
| 1035 | free (pool->buffers); |
---|
| 1036 | free (pool->bds); |
---|
| 1037 | return sc; |
---|
| 1038 | } |
---|
| 1039 | |
---|
| 1040 | sc = rtems_semaphore_create (rtems_build_name ('B', 'P', '0' + pid, 'w'), |
---|
| 1041 | 0, RTEMS_BDBUF_POOL_WAITER_ATTRIBS, 0, |
---|
| 1042 | &pool->waiting); |
---|
| 1043 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1044 | { |
---|
| 1045 | rtems_semaphore_delete (pool->transfer); |
---|
| 1046 | rtems_semaphore_delete (pool->access); |
---|
| 1047 | rtems_semaphore_delete (pool->sync_lock); |
---|
| 1048 | rtems_semaphore_delete (pool->lock); |
---|
| 1049 | free (pool->buffers); |
---|
| 1050 | free (pool->bds); |
---|
| 1051 | return sc; |
---|
| 1052 | } |
---|
| 1053 | |
---|
| 1054 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 1055 | } |
---|
| 1056 | |
---|
[c21c850e] | 1057 | /** |
---|
| 1058 | * Free resources allocated for buffer pool with specified number. |
---|
[e51bd96] | 1059 | * |
---|
[c21c850e] | 1060 | * @param pid Buffer pool number |
---|
[e51bd96] | 1061 | * |
---|
[c21c850e] | 1062 | * @retval RTEMS_SUCCESSFUL |
---|
[e51bd96] | 1063 | */ |
---|
| 1064 | static rtems_status_code |
---|
[3899a537] | 1065 | rtems_bdbuf_release_pool (rtems_bdpool_id pid) |
---|
[e51bd96] | 1066 | { |
---|
[3899a537] | 1067 | rtems_bdbuf_pool* pool = rtems_bdbuf_get_pool (pid); |
---|
| 1068 | |
---|
| 1069 | rtems_bdbuf_lock_pool (pool); |
---|
| 1070 | |
---|
| 1071 | rtems_semaphore_delete (pool->waiting); |
---|
| 1072 | rtems_semaphore_delete (pool->transfer); |
---|
| 1073 | rtems_semaphore_delete (pool->access); |
---|
| 1074 | rtems_semaphore_delete (pool->lock); |
---|
| 1075 | |
---|
| 1076 | free (pool->buffers); |
---|
| 1077 | free (pool->bds); |
---|
| 1078 | |
---|
| 1079 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 1080 | } |
---|
| 1081 | |
---|
[c21c850e] | 1082 | /** |
---|
| 1083 | * Prepare buffering layer to work - initialize buffer descritors and (if it is |
---|
| 1084 | * neccessary) buffers. Buffers will be allocated accoriding to the |
---|
| 1085 | * configuration table, each entry describes the size of block and the size of |
---|
| 1086 | * the pool. After initialization all blocks is placed into the ready state. |
---|
| 1087 | * lists. |
---|
[e51bd96] | 1088 | * |
---|
[c21c850e] | 1089 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1090 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1091 | */ |
---|
| 1092 | rtems_status_code |
---|
[a5fb40cf] | 1093 | rtems_bdbuf_init (void) |
---|
[e51bd96] | 1094 | { |
---|
[3899a537] | 1095 | rtems_bdpool_id p; |
---|
| 1096 | rtems_status_code sc; |
---|
[e51bd96] | 1097 | |
---|
[3899a537] | 1098 | #if RTEMS_BDBUF_TRACE |
---|
| 1099 | rtems_bdbuf_printf ("init\n"); |
---|
| 1100 | #endif |
---|
[048dcd2b] | 1101 | |
---|
[3899a537] | 1102 | if (rtems_bdbuf_pool_configuration_size <= 0) |
---|
| 1103 | return RTEMS_INVALID_SIZE; |
---|
[e51bd96] | 1104 | |
---|
[3899a537] | 1105 | if (rtems_bdbuf_ctx.npools) |
---|
| 1106 | return RTEMS_RESOURCE_IN_USE; |
---|
[e51bd96] | 1107 | |
---|
[3899a537] | 1108 | rtems_bdbuf_ctx.npools = rtems_bdbuf_pool_configuration_size; |
---|
[048dcd2b] | 1109 | |
---|
[3899a537] | 1110 | /* |
---|
| 1111 | * Allocate memory for buffer pool descriptors |
---|
| 1112 | */ |
---|
| 1113 | rtems_bdbuf_ctx.pool = calloc (rtems_bdbuf_pool_configuration_size, |
---|
| 1114 | sizeof (rtems_bdbuf_pool)); |
---|
| 1115 | |
---|
| 1116 | if (rtems_bdbuf_ctx.pool == NULL) |
---|
| 1117 | return RTEMS_NO_MEMORY; |
---|
| 1118 | |
---|
| 1119 | /* |
---|
| 1120 | * Initialize buffer pools and roll out if something failed, |
---|
| 1121 | */ |
---|
| 1122 | for (p = 0; p < rtems_bdbuf_ctx.npools; p++) |
---|
| 1123 | { |
---|
| 1124 | sc = rtems_bdbuf_initialize_pool (&rtems_bdbuf_pool_configuration[p], p); |
---|
| 1125 | if (sc != RTEMS_SUCCESSFUL) |
---|
[e51bd96] | 1126 | { |
---|
[3899a537] | 1127 | rtems_bdpool_id j; |
---|
| 1128 | for (j = 0; j < p - 1; j++) |
---|
| 1129 | rtems_bdbuf_release_pool (j); |
---|
| 1130 | return sc; |
---|
[e51bd96] | 1131 | } |
---|
[3899a537] | 1132 | } |
---|
[e51bd96] | 1133 | |
---|
[3899a537] | 1134 | /* |
---|
| 1135 | * Create and start swapout task |
---|
| 1136 | */ |
---|
[048dcd2b] | 1137 | |
---|
[3899a537] | 1138 | rtems_bdbuf_ctx.swapout_enabled = TRUE; |
---|
| 1139 | |
---|
| 1140 | sc = rtems_task_create (rtems_build_name('B', 'S', 'W', 'P'), |
---|
| 1141 | (rtems_bdbuf_configuration.swapout_priority ? |
---|
| 1142 | rtems_bdbuf_configuration.swapout_priority : |
---|
| 1143 | RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT), |
---|
| 1144 | SWAPOUT_TASK_STACK_SIZE, |
---|
| 1145 | RTEMS_PREEMPT | RTEMS_NO_TIMESLICE | RTEMS_NO_ASR, |
---|
| 1146 | RTEMS_LOCAL | RTEMS_NO_FLOATING_POINT, |
---|
| 1147 | &rtems_bdbuf_ctx.swapout); |
---|
| 1148 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1149 | { |
---|
| 1150 | for (p = 0; p < rtems_bdbuf_ctx.npools; p++) |
---|
| 1151 | rtems_bdbuf_release_pool (p); |
---|
| 1152 | free (rtems_bdbuf_ctx.pool); |
---|
| 1153 | return sc; |
---|
| 1154 | } |
---|
[e51bd96] | 1155 | |
---|
[3899a537] | 1156 | sc = rtems_task_start (rtems_bdbuf_ctx.swapout, |
---|
| 1157 | rtems_bdbuf_swapout_task, |
---|
| 1158 | (rtems_task_argument) &rtems_bdbuf_ctx); |
---|
| 1159 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1160 | { |
---|
| 1161 | rtems_task_delete (rtems_bdbuf_ctx.swapout); |
---|
| 1162 | for (p = 0; p < rtems_bdbuf_ctx.npools; p++) |
---|
| 1163 | rtems_bdbuf_release_pool (p); |
---|
| 1164 | free (rtems_bdbuf_ctx.pool); |
---|
| 1165 | return sc; |
---|
| 1166 | } |
---|
[e51bd96] | 1167 | |
---|
[3899a537] | 1168 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 1169 | } |
---|
| 1170 | |
---|
[3899a537] | 1171 | /** |
---|
| 1172 | * Get a buffer for this device and block. This function returns a buffer once |
---|
| 1173 | * placed into the AVL tree. If no buffer is available and it is not a read |
---|
[c21c850e] | 1174 | * ahead request and no buffers are waiting to the written to disk wait until |
---|
| 1175 | * one is available. If buffers are waiting to be written to disk and non are |
---|
| 1176 | * available expire the hold timer and wake the swap out task. If the buffer is |
---|
| 1177 | * for a read ahead transfer return NULL if there is not buffer or it is in the |
---|
| 1178 | * cache. |
---|
[e51bd96] | 1179 | * |
---|
[3899a537] | 1180 | * The AVL tree of buffers for the pool is searched and if not located check |
---|
| 1181 | * obtain a buffer and insert it into the AVL tree. Buffers are first obtained |
---|
[c21c850e] | 1182 | * from the ready list until all empty/ready buffers are used. Once all buffers |
---|
| 1183 | * are in use buffers are taken from the LRU list with the least recently used |
---|
[3899a537] | 1184 | * buffer taken first. A buffer taken from the LRU list is removed from the AVL |
---|
[c21c850e] | 1185 | * tree. The ready list or LRU list buffer is initialised to this device and |
---|
| 1186 | * block. If no buffers are available due to the ready and LRU lists being |
---|
| 1187 | * empty a check is made of the modified list. Buffers may be queued waiting |
---|
| 1188 | * for the hold timer to expire. These buffers should be written to disk and |
---|
| 1189 | * returned to the LRU list where they can be used rather than this call |
---|
| 1190 | * blocking. If buffers are on the modified list the max. write block size of |
---|
| 1191 | * buffers have their hold timer expired and the swap out task woken. The |
---|
| 1192 | * caller then blocks on the waiting semaphore and counter. When buffers return |
---|
| 1193 | * from the upper layers (access) or lower driver (transfer) the blocked caller |
---|
| 1194 | * task is woken and this procedure is repeated. The repeat handles a case of a |
---|
| 1195 | * another thread pre-empting getting a buffer first and adding it to the AVL |
---|
| 1196 | * tree. |
---|
[3899a537] | 1197 | * |
---|
| 1198 | * A buffer located in the AVL tree means it is already in the cache and maybe |
---|
| 1199 | * in use somewhere. The buffer can be either: |
---|
[e51bd96] | 1200 | * |
---|
[3899a537] | 1201 | * # Cached. Not being accessed or part of a media transfer. |
---|
[c21c850e] | 1202 | * # Access or modifed access. Is with an upper layer being accessed. |
---|
[3899a537] | 1203 | * # Transfer. Is with the driver and part of a media transfer. |
---|
| 1204 | * |
---|
[c21c850e] | 1205 | * If cached we assign the new state, extract it from any list it maybe part of |
---|
| 1206 | * and return to the user. |
---|
[3899a537] | 1207 | * |
---|
| 1208 | * This function assumes the pool the buffer is being taken from is locked and |
---|
[c21c850e] | 1209 | * it will make sure the pool is locked when it returns. The pool will be |
---|
| 1210 | * unlocked if the call could block. |
---|
[3899a537] | 1211 | * |
---|
| 1212 | * @param device The physical disk device |
---|
[c21c850e] | 1213 | * @param pool The pool reference |
---|
| 1214 | * @param block Absolute media block number |
---|
| 1215 | * @param read_ahead The get is for a read ahead buffer |
---|
[e51bd96] | 1216 | * |
---|
[c21c850e] | 1217 | * @return RTEMS status code ( if operation completed successfully or error |
---|
| 1218 | * code if error is occured) |
---|
[e51bd96] | 1219 | */ |
---|
[3899a537] | 1220 | static rtems_bdbuf_buffer* |
---|
| 1221 | rtems_bdbuf_get_buffer (rtems_disk_device* pdd, |
---|
| 1222 | rtems_bdbuf_pool* pool, |
---|
| 1223 | rtems_blkdev_bnum block, |
---|
| 1224 | boolean read_ahead) |
---|
[e51bd96] | 1225 | { |
---|
[3899a537] | 1226 | dev_t device = pdd->dev; |
---|
| 1227 | rtems_bdbuf_buffer* bd; |
---|
| 1228 | boolean available; |
---|
| 1229 | |
---|
| 1230 | /* |
---|
| 1231 | * Loop until we get a buffer. Under load we could find no buffers are |
---|
[c21c850e] | 1232 | * available requiring this task to wait until some become available before |
---|
| 1233 | * proceeding. There is no timeout. If the call is to block and the buffer is |
---|
[3899a537] | 1234 | * for a read ahead buffer return NULL. |
---|
| 1235 | * |
---|
| 1236 | * The search procedure is repeated as another thread could have pre-empted |
---|
| 1237 | * us while we waited for a buffer, obtained an empty buffer and loaded the |
---|
[c21c850e] | 1238 | * AVL tree with the one we are after. |
---|
[3899a537] | 1239 | */ |
---|
| 1240 | do |
---|
| 1241 | { |
---|
| 1242 | /* |
---|
| 1243 | * Search for buffer descriptor for this dev/block key. |
---|
| 1244 | */ |
---|
| 1245 | bd = rtems_bdbuf_avl_search (&pool->tree, device, block); |
---|
[048dcd2b] | 1246 | |
---|
[3899a537] | 1247 | /* |
---|
| 1248 | * No buffer in the cache for this block. We need to obtain a buffer and |
---|
| 1249 | * this means take a buffer that is ready to use. If all buffers are in use |
---|
| 1250 | * take the least recently used buffer. If there are none then the cache is |
---|
| 1251 | * empty. All the buffers are either queued to be written to disk or with |
---|
| 1252 | * the user. We cannot do much with the buffers with the user how-ever with |
---|
| 1253 | * the modified buffers waiting to be written to disk flush the maximum |
---|
[c21c850e] | 1254 | * number transfered in a block to disk. After this all that can be done is |
---|
| 1255 | * to wait for a buffer to return to the cache. |
---|
[3899a537] | 1256 | */ |
---|
| 1257 | if (!bd) |
---|
[e51bd96] | 1258 | { |
---|
[3899a537] | 1259 | /* |
---|
| 1260 | * Assign new buffer descriptor from the empty list if one is present. If |
---|
| 1261 | * the empty queue is empty get the oldest buffer from LRU list. If the |
---|
[c21c850e] | 1262 | * LRU list is empty there are no available buffers check the modified |
---|
| 1263 | * list. |
---|
[3899a537] | 1264 | */ |
---|
| 1265 | if (rtems_chain_is_empty (&pool->ready)) |
---|
| 1266 | { |
---|
| 1267 | /* |
---|
| 1268 | * No unsed or read-ahead buffers. |
---|
| 1269 | * |
---|
[c21c850e] | 1270 | * If this is a read ahead buffer just return. No need to place further |
---|
| 1271 | * pressure on the cache by reading something that may be needed when |
---|
| 1272 | * we have data in the cache that was needed and may still be. |
---|
[3899a537] | 1273 | */ |
---|
| 1274 | if (read_ahead) |
---|
| 1275 | return NULL; |
---|
| 1276 | |
---|
| 1277 | /* |
---|
| 1278 | * Check the LRU list. |
---|
| 1279 | */ |
---|
| 1280 | bd = (rtems_bdbuf_buffer *) rtems_chain_get (&pool->lru); |
---|
| 1281 | |
---|
| 1282 | if (bd) |
---|
[e51bd96] | 1283 | { |
---|
[3899a537] | 1284 | /* |
---|
| 1285 | * Remove the buffer from the AVL tree. |
---|
| 1286 | */ |
---|
| 1287 | if (rtems_bdbuf_avl_remove (&pool->tree, bd) != 0) |
---|
| 1288 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
[e51bd96] | 1289 | } |
---|
| 1290 | else |
---|
| 1291 | { |
---|
[3899a537] | 1292 | /* |
---|
| 1293 | * If there are buffers on the modified list expire the hold timer |
---|
[c21c850e] | 1294 | * and wake the swap out task then wait else just go and wait. |
---|
[3899a537] | 1295 | */ |
---|
| 1296 | if (!rtems_chain_is_empty (&pool->modified)) |
---|
| 1297 | { |
---|
| 1298 | rtems_chain_node* node = rtems_chain_head (&pool->modified); |
---|
| 1299 | int write_blocks = 0; |
---|
| 1300 | |
---|
| 1301 | node = node->next; |
---|
| 1302 | while ((write_blocks < rtems_bdbuf_configuration.max_write_blocks) && |
---|
| 1303 | !rtems_chain_is_tail (&pool->modified, node)) |
---|
[e51bd96] | 1304 | { |
---|
[3899a537] | 1305 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
| 1306 | bd->hold_timer = 0; |
---|
| 1307 | write_blocks++; |
---|
| 1308 | node = node->next; |
---|
[e51bd96] | 1309 | } |
---|
| 1310 | |
---|
[3899a537] | 1311 | rtems_bdbuf_wake_swapper (); |
---|
| 1312 | } |
---|
| 1313 | |
---|
| 1314 | /* |
---|
| 1315 | * Wait for a buffer to be returned to the pool. The buffer will be |
---|
| 1316 | * placed on the LRU list. |
---|
| 1317 | */ |
---|
| 1318 | rtems_bdbuf_wait (pool, &pool->waiting, &pool->wait_waiters); |
---|
[e51bd96] | 1319 | } |
---|
[3899a537] | 1320 | } |
---|
| 1321 | else |
---|
| 1322 | { |
---|
| 1323 | bd = (rtems_bdbuf_buffer *) rtems_chain_get (&(pool->ready)); |
---|
[e51bd96] | 1324 | |
---|
[3899a537] | 1325 | if ((bd->state != RTEMS_BDBUF_STATE_EMPTY) && |
---|
| 1326 | (bd->state != RTEMS_BDBUF_STATE_READ_AHEAD)) |
---|
| 1327 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
| 1328 | |
---|
| 1329 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
[e51bd96] | 1330 | { |
---|
[3899a537] | 1331 | if (rtems_bdbuf_avl_remove (&pool->tree, bd) != 0) |
---|
| 1332 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
[e51bd96] | 1333 | } |
---|
[3899a537] | 1334 | } |
---|
| 1335 | |
---|
| 1336 | if (bd) |
---|
| 1337 | { |
---|
| 1338 | bd->dev = device; |
---|
| 1339 | bd->block = block; |
---|
| 1340 | bd->avl.left = NULL; |
---|
| 1341 | bd->avl.right = NULL; |
---|
| 1342 | bd->state = RTEMS_BDBUF_STATE_EMPTY; |
---|
| 1343 | bd->error = 0; |
---|
| 1344 | bd->waiters = 0; |
---|
| 1345 | |
---|
| 1346 | if (rtems_bdbuf_avl_insert (&pool->tree, bd) != 0) |
---|
| 1347 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
| 1348 | |
---|
| 1349 | return bd; |
---|
| 1350 | } |
---|
[e51bd96] | 1351 | } |
---|
[3899a537] | 1352 | } |
---|
| 1353 | while (!bd); |
---|
| 1354 | |
---|
| 1355 | /* |
---|
| 1356 | * If the buffer is for read ahead and it exists in the AVL cache or is being |
---|
| 1357 | * accessed or being transfered then return NULL. |
---|
| 1358 | */ |
---|
| 1359 | if (read_ahead) |
---|
| 1360 | return NULL; |
---|
| 1361 | |
---|
| 1362 | /* |
---|
[c21c850e] | 1363 | * Loop waiting for the buffer to enter the cached state. If the buffer is in |
---|
| 1364 | * the access or transfer state then wait until it is not. |
---|
[3899a537] | 1365 | */ |
---|
| 1366 | available = FALSE; |
---|
| 1367 | while (!available) |
---|
| 1368 | { |
---|
| 1369 | switch (bd->state) |
---|
[e51bd96] | 1370 | { |
---|
[3899a537] | 1371 | case RTEMS_BDBUF_STATE_CACHED: |
---|
| 1372 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
| 1373 | case RTEMS_BDBUF_STATE_READ_AHEAD: |
---|
| 1374 | available = TRUE; |
---|
| 1375 | break; |
---|
| 1376 | |
---|
| 1377 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
| 1378 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
| 1379 | bd->waiters++; |
---|
| 1380 | rtems_bdbuf_wait (pool, &pool->access, &pool->access_waiters); |
---|
| 1381 | bd->waiters--; |
---|
| 1382 | break; |
---|
| 1383 | |
---|
| 1384 | case RTEMS_BDBUF_STATE_SYNC: |
---|
| 1385 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
| 1386 | bd->waiters++; |
---|
| 1387 | rtems_bdbuf_wait (pool, &pool->transfer, &pool->transfer_waiters); |
---|
| 1388 | bd->waiters--; |
---|
| 1389 | break; |
---|
| 1390 | |
---|
| 1391 | default: |
---|
| 1392 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
[e51bd96] | 1393 | } |
---|
[3899a537] | 1394 | } |
---|
[048dcd2b] | 1395 | |
---|
[3899a537] | 1396 | /* |
---|
| 1397 | * Buffer is linked to the LRU, modifed, or sync lists. Remove it from there. |
---|
| 1398 | */ |
---|
| 1399 | rtems_chain_extract (&bd->link); |
---|
[e51bd96] | 1400 | |
---|
[3899a537] | 1401 | return bd; |
---|
[e51bd96] | 1402 | } |
---|
| 1403 | |
---|
[3899a537] | 1404 | /** |
---|
[c21c850e] | 1405 | * Get block buffer for data to be written into. The buffers is set to the |
---|
| 1406 | * access or modifed access state. If the buffer is in the cache and modified |
---|
| 1407 | * the state is access modified else the state is access. This buffer contents |
---|
| 1408 | * are not initialised if the buffer is not already in the cache. If the block |
---|
| 1409 | * is already resident in memory it is returned how-ever if not in memory the |
---|
| 1410 | * buffer is not read from disk. This call is used when writing the whole block |
---|
| 1411 | * on a disk rather than just changing a part of it. If there is no buffers |
---|
| 1412 | * available this call will block. A buffer obtained with this call will not be |
---|
| 1413 | * involved in a transfer request and will not be returned to another user |
---|
| 1414 | * until released. If the buffer is already with a user when this call is made |
---|
| 1415 | * the call is blocked until the buffer is returned. The highest priority |
---|
| 1416 | * waiter will obtain the buffer first. |
---|
| 1417 | * |
---|
| 1418 | * The block number is the linear block number. This is relative to the start |
---|
| 1419 | * of the partition on the media. |
---|
| 1420 | * |
---|
| 1421 | * @param device Device number (constructed of major and minor device number) |
---|
| 1422 | * @param block Linear media block number |
---|
| 1423 | * @param bd Reference to the buffer descriptor pointer. |
---|
| 1424 | * |
---|
| 1425 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1426 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1427 | */ |
---|
[3899a537] | 1428 | rtems_status_code |
---|
| 1429 | rtems_bdbuf_get (dev_t device, |
---|
| 1430 | rtems_blkdev_bnum block, |
---|
| 1431 | rtems_bdbuf_buffer** bdp) |
---|
[e51bd96] | 1432 | { |
---|
[3899a537] | 1433 | rtems_disk_device* dd; |
---|
| 1434 | rtems_bdbuf_pool* pool; |
---|
| 1435 | rtems_bdbuf_buffer* bd; |
---|
| 1436 | |
---|
| 1437 | /* |
---|
| 1438 | * Do not hold the pool lock when obtaining the disk table. |
---|
| 1439 | */ |
---|
| 1440 | dd = rtems_disk_obtain (device); |
---|
| 1441 | if (dd == NULL) |
---|
| 1442 | return RTEMS_INVALID_ID; |
---|
| 1443 | |
---|
| 1444 | if (block >= dd->size) |
---|
| 1445 | { |
---|
| 1446 | rtems_disk_release (dd); |
---|
| 1447 | return RTEMS_INVALID_NUMBER; |
---|
| 1448 | } |
---|
| 1449 | |
---|
| 1450 | block += dd->start; |
---|
| 1451 | |
---|
| 1452 | pool = rtems_bdbuf_get_pool (dd->phys_dev->pool); |
---|
| 1453 | |
---|
| 1454 | rtems_disk_release(dd); |
---|
| 1455 | |
---|
| 1456 | rtems_bdbuf_lock_pool (pool); |
---|
| 1457 | |
---|
| 1458 | #if RTEMS_BDBUF_TRACE |
---|
| 1459 | rtems_bdbuf_printf ("get: %d (dev = %08x)\n", block, device); |
---|
| 1460 | #endif |
---|
| 1461 | |
---|
| 1462 | bd = rtems_bdbuf_get_buffer (dd->phys_dev, pool, block, FALSE); |
---|
| 1463 | |
---|
| 1464 | if (bd->state == RTEMS_BDBUF_STATE_MODIFIED) |
---|
| 1465 | bd->state = RTEMS_BDBUF_STATE_ACCESS_MODIFIED; |
---|
| 1466 | else |
---|
| 1467 | bd->state = RTEMS_BDBUF_STATE_ACCESS; |
---|
| 1468 | |
---|
| 1469 | rtems_bdbuf_unlock_pool (pool); |
---|
| 1470 | |
---|
| 1471 | *bdp = bd; |
---|
| 1472 | |
---|
| 1473 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 1474 | } |
---|
| 1475 | |
---|
[c21c850e] | 1476 | /** |
---|
| 1477 | * Call back handler called by the low level driver when the transfer has |
---|
| 1478 | * completed. This function may be invoked from interrupt handler. |
---|
[e51bd96] | 1479 | * |
---|
[c21c850e] | 1480 | * @param arg Arbitrary argument specified in block device request |
---|
| 1481 | * structure (in this case - pointer to the appropriate |
---|
| 1482 | * block device request structure). |
---|
| 1483 | * @param status I/O completion status |
---|
| 1484 | * @param error errno error code if status != RTEMS_SUCCESSFUL |
---|
[e51bd96] | 1485 | */ |
---|
| 1486 | static void |
---|
[3899a537] | 1487 | rtems_bdbuf_read_done (void* arg, rtems_status_code status, int error) |
---|
[e51bd96] | 1488 | { |
---|
[3899a537] | 1489 | rtems_blkdev_request* req = (rtems_blkdev_request*) arg; |
---|
| 1490 | |
---|
| 1491 | req->error = error; |
---|
| 1492 | req->status = status; |
---|
| 1493 | |
---|
| 1494 | rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
[e51bd96] | 1495 | } |
---|
| 1496 | |
---|
[3899a537] | 1497 | /** |
---|
[c21c850e] | 1498 | * Get the block buffer and if not already in the cache read from the disk. If |
---|
| 1499 | * specified block already cached return. The buffer is set to the access or |
---|
| 1500 | * modifed access state. If the buffer is in the cache and modified the state |
---|
| 1501 | * is access modified else the state is access. If block is already being read |
---|
| 1502 | * from disk for being written to disk this call blocks. If the buffer is |
---|
| 1503 | * waiting to be written it is removed from modified queue and returned to the |
---|
| 1504 | * user. If the buffer is not in the cache a new buffer is obtained and the |
---|
| 1505 | * data read from disk. The call may block until these operations complete. A |
---|
| 1506 | * buffer obtained with this call will not be involved in a transfer request |
---|
| 1507 | * and will not be returned to another user until released. If the buffer is |
---|
| 1508 | * already with a user when this call is made the call is blocked until the |
---|
| 1509 | * buffer is returned. The highest priority waiter will obtain the buffer |
---|
| 1510 | * first. |
---|
| 1511 | * |
---|
| 1512 | * @param device Device number (constructed of major and minor device number) |
---|
| 1513 | * @param block Linear media block number |
---|
| 1514 | * @param bd Reference to the buffer descriptor pointer. |
---|
[e51bd96] | 1515 | * |
---|
[c21c850e] | 1516 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1517 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1518 | */ |
---|
| 1519 | rtems_status_code |
---|
[3899a537] | 1520 | rtems_bdbuf_read (dev_t device, |
---|
| 1521 | rtems_blkdev_bnum block, |
---|
| 1522 | rtems_bdbuf_buffer** bdp) |
---|
[e51bd96] | 1523 | { |
---|
[3899a537] | 1524 | rtems_disk_device* dd; |
---|
| 1525 | rtems_bdbuf_pool* pool; |
---|
| 1526 | rtems_bdbuf_buffer* bd = NULL; |
---|
| 1527 | int read_ahead_count; |
---|
| 1528 | rtems_blkdev_request* req; |
---|
| 1529 | |
---|
| 1530 | /* |
---|
| 1531 | * @todo This type of request structure is wrong and should be removed. |
---|
| 1532 | */ |
---|
| 1533 | #define bdbuf_alloc(size) __builtin_alloca (size) |
---|
| 1534 | |
---|
| 1535 | req = bdbuf_alloc (sizeof (rtems_blkdev_request) + |
---|
| 1536 | (sizeof ( rtems_blkdev_sg_buffer) * |
---|
| 1537 | rtems_bdbuf_configuration.max_read_ahead_blocks)); |
---|
| 1538 | |
---|
| 1539 | /* |
---|
| 1540 | * Do not hold the pool lock when obtaining the disk table. |
---|
| 1541 | */ |
---|
| 1542 | dd = rtems_disk_obtain (device); |
---|
| 1543 | if (dd == NULL) |
---|
| 1544 | return RTEMS_INVALID_ID; |
---|
| 1545 | |
---|
| 1546 | block += dd->start; |
---|
| 1547 | |
---|
| 1548 | #if RTEMS_BDBUF_TRACE |
---|
| 1549 | rtems_bdbuf_printf ("read: %d (dev = %08x)\n", block, device); |
---|
| 1550 | #endif |
---|
| 1551 | |
---|
| 1552 | if (block >= dd->size) |
---|
| 1553 | { |
---|
| 1554 | rtems_disk_release(dd); |
---|
| 1555 | return RTEMS_INVALID_NUMBER; |
---|
| 1556 | } |
---|
[048dcd2b] | 1557 | |
---|
[3899a537] | 1558 | req->count = 0; |
---|
| 1559 | req->bufnum = 0; |
---|
[e51bd96] | 1560 | |
---|
[3899a537] | 1561 | /* |
---|
| 1562 | * Read the block plus the required number of blocks ahead. The number of |
---|
| 1563 | * blocks to read ahead is configured by the user and limited by the size of |
---|
| 1564 | * the disk or reaching a read ahead block that is also cached. |
---|
| 1565 | * |
---|
| 1566 | * Limit the blocks read by the size of the disk. |
---|
| 1567 | */ |
---|
| 1568 | if ((rtems_bdbuf_configuration.max_read_ahead_blocks + block) < dd->size) |
---|
| 1569 | read_ahead_count = rtems_bdbuf_configuration.max_read_ahead_blocks; |
---|
| 1570 | else |
---|
| 1571 | read_ahead_count = dd->size - block; |
---|
[048dcd2b] | 1572 | |
---|
[3899a537] | 1573 | pool = rtems_bdbuf_get_pool (dd->phys_dev->pool); |
---|
[048dcd2b] | 1574 | |
---|
[3899a537] | 1575 | rtems_bdbuf_lock_pool (pool); |
---|
[e51bd96] | 1576 | |
---|
[3899a537] | 1577 | while (req->count < read_ahead_count) |
---|
| 1578 | { |
---|
| 1579 | /* |
---|
| 1580 | * Get the buffer for the requested block. If the block is cached then |
---|
| 1581 | * return it. If it is not cached transfer the block from the disk media |
---|
| 1582 | * into memory. |
---|
| 1583 | * |
---|
| 1584 | * We need to clean up any buffers allocated and not passed back to the |
---|
| 1585 | * caller. |
---|
| 1586 | */ |
---|
| 1587 | bd = rtems_bdbuf_get_buffer (dd->phys_dev, pool, |
---|
| 1588 | block + req->count, |
---|
| 1589 | req->count == 0 ? FALSE : TRUE); |
---|
[e51bd96] | 1590 | |
---|
[3899a537] | 1591 | /* |
---|
| 1592 | * Read ahead buffer is in the cache or none available. Read what we |
---|
| 1593 | * can. |
---|
| 1594 | */ |
---|
| 1595 | if (!bd) |
---|
| 1596 | break; |
---|
[e51bd96] | 1597 | |
---|
[3899a537] | 1598 | /* |
---|
| 1599 | * Is the block we are interested in the cache ? |
---|
| 1600 | */ |
---|
| 1601 | if ((bd->state == RTEMS_BDBUF_STATE_CACHED) || |
---|
| 1602 | (bd->state == RTEMS_BDBUF_STATE_MODIFIED)) |
---|
| 1603 | break; |
---|
[048dcd2b] | 1604 | |
---|
[3899a537] | 1605 | bd->state = RTEMS_BDBUF_STATE_TRANSFER; |
---|
| 1606 | bd->error = 0; |
---|
[e51bd96] | 1607 | |
---|
[3899a537] | 1608 | /* |
---|
[c21c850e] | 1609 | * @todo The use of these req blocks is not a great design. The req is a |
---|
| 1610 | * struct with a single 'bufs' declared in the req struct and the |
---|
| 1611 | * others are added in the outer level struct. This relies on the |
---|
| 1612 | * structs joining as a single array and that assumes the compiler |
---|
| 1613 | * packs the structs. Why not just place on a list ? The BD has a |
---|
| 1614 | * node that can be used. |
---|
[3899a537] | 1615 | */ |
---|
| 1616 | req->bufs[req->count].user = bd; |
---|
| 1617 | req->bufs[req->count].block = bd->block; |
---|
| 1618 | req->bufs[req->count].length = dd->block_size; |
---|
| 1619 | req->bufs[req->count].buffer = bd->buffer; |
---|
| 1620 | req->count++; |
---|
| 1621 | req->bufnum++; |
---|
| 1622 | } |
---|
[0ebfac19] | 1623 | |
---|
[3899a537] | 1624 | /* |
---|
| 1625 | * Transfer any requested buffers. If the request count is 0 we have found |
---|
| 1626 | * the block in the cache so return it. |
---|
| 1627 | */ |
---|
| 1628 | if (req->count) |
---|
| 1629 | { |
---|
| 1630 | /* |
---|
| 1631 | * Unlock the pool. We have the buffer for the block and it will be in the |
---|
| 1632 | * access or transfer state. We may also have a number of read ahead blocks |
---|
| 1633 | * if we need to transfer data. At this point any other threads can gain |
---|
| 1634 | * access to the pool and if they are after any of the buffers we have they |
---|
| 1635 | * will block and be woken when the buffer is returned to the pool. |
---|
| 1636 | * |
---|
| 1637 | * If a transfer is needed the I/O operation will occur with pre-emption |
---|
| 1638 | * enabled and the pool unlocked. This is a change to the previous version |
---|
| 1639 | * of the bdbuf code. |
---|
| 1640 | */ |
---|
[0ebfac19] | 1641 | int result; |
---|
[3899a537] | 1642 | int b; |
---|
| 1643 | |
---|
| 1644 | rtems_bdbuf_unlock_pool (pool); |
---|
| 1645 | |
---|
| 1646 | req->req = RTEMS_BLKDEV_REQ_READ; |
---|
| 1647 | req->req_done = rtems_bdbuf_read_done; |
---|
| 1648 | req->done_arg = req; |
---|
| 1649 | req->io_task = rtems_task_self (); |
---|
| 1650 | req->status = RTEMS_RESOURCE_IN_USE; |
---|
| 1651 | req->error = 0; |
---|
| 1652 | req->start = dd->start; |
---|
| 1653 | |
---|
| 1654 | result = dd->ioctl (dd->phys_dev->dev, RTEMS_BLKIO_REQUEST, req); |
---|
| 1655 | |
---|
| 1656 | /* |
---|
| 1657 | * Inspection of the DOS FS code shows the result from this function is |
---|
| 1658 | * handled and a buffer must be returned. |
---|
| 1659 | */ |
---|
| 1660 | if (result < 0) |
---|
[0ebfac19] | 1661 | { |
---|
[3899a537] | 1662 | req->error = errno; |
---|
| 1663 | req->status = RTEMS_IO_ERROR; |
---|
| 1664 | } |
---|
| 1665 | else |
---|
| 1666 | { |
---|
| 1667 | rtems_status_code sc; |
---|
| 1668 | rtems_event_set out; |
---|
| 1669 | sc = rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
| 1670 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
| 1671 | 0, &out); |
---|
| 1672 | |
---|
| 1673 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1674 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
[0ebfac19] | 1675 | } |
---|
| 1676 | |
---|
[3899a537] | 1677 | rtems_bdbuf_lock_pool (pool); |
---|
[0ebfac19] | 1678 | |
---|
[3899a537] | 1679 | for (b = 1; b < req->count; b++) |
---|
[0ebfac19] | 1680 | { |
---|
[3899a537] | 1681 | bd = req->bufs[b].user; |
---|
| 1682 | bd->error = req->error; |
---|
| 1683 | bd->state = RTEMS_BDBUF_STATE_READ_AHEAD; |
---|
| 1684 | rtems_bdbuf_release (bd); |
---|
[0ebfac19] | 1685 | } |
---|
| 1686 | |
---|
[3899a537] | 1687 | bd = req->bufs[0].user; |
---|
| 1688 | } |
---|
[0ebfac19] | 1689 | |
---|
[3899a537] | 1690 | /* |
---|
| 1691 | * The data for this block is cached in the buffer. |
---|
| 1692 | */ |
---|
| 1693 | if (bd->state == RTEMS_BDBUF_STATE_MODIFIED) |
---|
| 1694 | bd->state = RTEMS_BDBUF_STATE_ACCESS_MODIFIED; |
---|
| 1695 | else |
---|
| 1696 | bd->state = RTEMS_BDBUF_STATE_ACCESS; |
---|
[048dcd2b] | 1697 | |
---|
[3899a537] | 1698 | rtems_bdbuf_unlock_pool (pool); |
---|
| 1699 | rtems_disk_release (dd); |
---|
[0ebfac19] | 1700 | |
---|
[3899a537] | 1701 | *bdp = bd; |
---|
[e51bd96] | 1702 | |
---|
[3899a537] | 1703 | return RTEMS_SUCCESSFUL; |
---|
| 1704 | } |
---|
[e51bd96] | 1705 | |
---|
[3899a537] | 1706 | /** |
---|
[c21c850e] | 1707 | * Release the buffer obtained by a read call back to the cache. If the buffer |
---|
| 1708 | * was obtained by a get call and was not already in the cache the release |
---|
| 1709 | * modified call should be used. A buffer released with this call obtained by a |
---|
| 1710 | * get call may not be in sync with the contents on disk. If the buffer was in |
---|
| 1711 | * the cache and modified before this call it will be returned to the modified |
---|
| 1712 | * queue. The buffers is returned to the end of the LRU list. |
---|
[e51bd96] | 1713 | * |
---|
[c21c850e] | 1714 | * @param bd Reference to the buffer descriptor. |
---|
[e51bd96] | 1715 | * |
---|
[c21c850e] | 1716 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1717 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1718 | */ |
---|
[3899a537] | 1719 | rtems_status_code |
---|
| 1720 | rtems_bdbuf_release (rtems_bdbuf_buffer* bd) |
---|
[e51bd96] | 1721 | { |
---|
[3899a537] | 1722 | rtems_bdbuf_pool* pool; |
---|
[e51bd96] | 1723 | |
---|
[3899a537] | 1724 | if (bd == NULL) |
---|
| 1725 | return RTEMS_INVALID_ADDRESS; |
---|
[048dcd2b] | 1726 | |
---|
[3899a537] | 1727 | pool = rtems_bdbuf_get_pool (bd->pool); |
---|
[e51bd96] | 1728 | |
---|
[3899a537] | 1729 | rtems_bdbuf_lock_pool (pool); |
---|
[e51bd96] | 1730 | |
---|
[3899a537] | 1731 | #if RTEMS_BDBUF_TRACE |
---|
| 1732 | rtems_bdbuf_printf ("release: %d\n", bd->block); |
---|
| 1733 | #endif |
---|
| 1734 | |
---|
| 1735 | if (bd->state == RTEMS_BDBUF_STATE_ACCESS_MODIFIED) |
---|
| 1736 | { |
---|
| 1737 | rtems_bdbuf_append_modified (pool, bd); |
---|
| 1738 | } |
---|
| 1739 | else |
---|
| 1740 | { |
---|
| 1741 | /* |
---|
[c21c850e] | 1742 | * If this is a read ahead buffer place the ready queue. Buffers are taken |
---|
| 1743 | * from here first. If we prepend then get from the queue the buffers |
---|
| 1744 | * furthermost from the read buffer will be used. |
---|
[3899a537] | 1745 | */ |
---|
| 1746 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
| 1747 | rtems_chain_prepend (&pool->ready, &bd->link); |
---|
| 1748 | else |
---|
[e51bd96] | 1749 | { |
---|
[3899a537] | 1750 | bd->state = RTEMS_BDBUF_STATE_CACHED; |
---|
| 1751 | rtems_chain_append (&pool->lru, &bd->link); |
---|
[e51bd96] | 1752 | } |
---|
[3899a537] | 1753 | } |
---|
| 1754 | |
---|
| 1755 | /* |
---|
| 1756 | * If there are threads waiting to access the buffer wake them. Wake any |
---|
| 1757 | * waiters if this is the first buffer to placed back onto the queue. |
---|
| 1758 | */ |
---|
| 1759 | if (bd->waiters) |
---|
| 1760 | rtems_bdbuf_wake (pool->access, &pool->access_waiters); |
---|
| 1761 | else |
---|
| 1762 | { |
---|
| 1763 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
| 1764 | { |
---|
| 1765 | if (rtems_chain_has_only_one_node (&pool->ready)) |
---|
| 1766 | rtems_bdbuf_wake (pool->waiting, &pool->wait_waiters); |
---|
| 1767 | } |
---|
| 1768 | else |
---|
| 1769 | { |
---|
| 1770 | if (rtems_chain_has_only_one_node (&pool->lru)) |
---|
| 1771 | rtems_bdbuf_wake (pool->waiting, &pool->wait_waiters); |
---|
| 1772 | } |
---|
| 1773 | } |
---|
| 1774 | |
---|
| 1775 | rtems_bdbuf_unlock_pool (pool); |
---|
[e51bd96] | 1776 | |
---|
[3899a537] | 1777 | return RTEMS_SUCCESSFUL; |
---|
| 1778 | } |
---|
[e51bd96] | 1779 | |
---|
[3899a537] | 1780 | /** |
---|
[c21c850e] | 1781 | * Release the buffer allocated with a get or read call placing it on the |
---|
| 1782 | * modidied list. If the buffer was not released modified before the hold |
---|
| 1783 | * timer is set to the configuration value. If the buffer had been released |
---|
| 1784 | * modified before but not written to disk the hold timer is not updated. The |
---|
| 1785 | * buffer will be written to disk when the hold timer has expired, there are |
---|
| 1786 | * not more buffers available in the cache and a get or read buffer needs one |
---|
| 1787 | * or a sync call has been made. If the buffer is obtained with a get or read |
---|
| 1788 | * before the hold timer has expired the buffer will be returned to the user. |
---|
[e51bd96] | 1789 | * |
---|
[c21c850e] | 1790 | * @param bd Reference to the buffer descriptor. |
---|
[e51bd96] | 1791 | * |
---|
[c21c850e] | 1792 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1793 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1794 | */ |
---|
| 1795 | rtems_status_code |
---|
[3899a537] | 1796 | rtems_bdbuf_release_modified (rtems_bdbuf_buffer* bd) |
---|
[e51bd96] | 1797 | { |
---|
[3899a537] | 1798 | rtems_bdbuf_pool* pool; |
---|
| 1799 | |
---|
| 1800 | if (bd == NULL) |
---|
| 1801 | return RTEMS_INVALID_ADDRESS; |
---|
[e51bd96] | 1802 | |
---|
[3899a537] | 1803 | pool = rtems_bdbuf_get_pool (bd->pool); |
---|
[048dcd2b] | 1804 | |
---|
[3899a537] | 1805 | rtems_bdbuf_lock_pool (pool); |
---|
[048dcd2b] | 1806 | |
---|
[3899a537] | 1807 | #if RTEMS_BDBUF_TRACE |
---|
| 1808 | rtems_bdbuf_printf ("release modified: %d\n", bd->block); |
---|
| 1809 | #endif |
---|
| 1810 | |
---|
| 1811 | bd->hold_timer = rtems_bdbuf_configuration.swap_block_hold; |
---|
| 1812 | |
---|
| 1813 | rtems_bdbuf_append_modified (pool, bd); |
---|
[048dcd2b] | 1814 | |
---|
[3899a537] | 1815 | if (bd->waiters) |
---|
| 1816 | rtems_bdbuf_wake (pool->access, &pool->access_waiters); |
---|
| 1817 | |
---|
| 1818 | rtems_bdbuf_unlock_pool (pool); |
---|
[048dcd2b] | 1819 | |
---|
[3899a537] | 1820 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 1821 | } |
---|
| 1822 | |
---|
[3899a537] | 1823 | /** |
---|
[c21c850e] | 1824 | * Release the buffer as modified and wait until it has been synchronized with |
---|
| 1825 | * the disk by writing it. This buffer will be the first to be transfer to disk |
---|
| 1826 | * and other buffers may also be written if the maximum number of blocks in a |
---|
| 1827 | * requests allows it. |
---|
[e51bd96] | 1828 | * |
---|
[3899a537] | 1829 | * @note This code does not lock the sync mutex and stop additions to the |
---|
[c21c850e] | 1830 | * modified queue. |
---|
| 1831 | * |
---|
| 1832 | * @param bd Reference to the buffer descriptor. |
---|
[e51bd96] | 1833 | * |
---|
[c21c850e] | 1834 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1835 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1836 | */ |
---|
| 1837 | rtems_status_code |
---|
[3899a537] | 1838 | rtems_bdbuf_sync (rtems_bdbuf_buffer* bd) |
---|
[e51bd96] | 1839 | { |
---|
[3899a537] | 1840 | rtems_bdbuf_pool* pool; |
---|
| 1841 | boolean available; |
---|
| 1842 | |
---|
| 1843 | #if RTEMS_BDBUF_TRACE |
---|
| 1844 | rtems_bdbuf_printf ("sync: %d\n", bd->block); |
---|
| 1845 | #endif |
---|
| 1846 | |
---|
| 1847 | if (bd == NULL) |
---|
| 1848 | return RTEMS_INVALID_ADDRESS; |
---|
| 1849 | |
---|
| 1850 | pool = rtems_bdbuf_get_pool (bd->pool); |
---|
| 1851 | |
---|
| 1852 | rtems_bdbuf_lock_pool (pool); |
---|
| 1853 | |
---|
| 1854 | bd->state = RTEMS_BDBUF_STATE_SYNC; |
---|
[e51bd96] | 1855 | |
---|
[3899a537] | 1856 | rtems_chain_append (&pool->sync, &bd->link); |
---|
[048dcd2b] | 1857 | |
---|
[3899a537] | 1858 | rtems_bdbuf_wake_swapper (); |
---|
[e51bd96] | 1859 | |
---|
[3899a537] | 1860 | available = FALSE; |
---|
| 1861 | while (!available) |
---|
| 1862 | { |
---|
| 1863 | switch (bd->state) |
---|
[e51bd96] | 1864 | { |
---|
[3899a537] | 1865 | case RTEMS_BDBUF_STATE_CACHED: |
---|
| 1866 | case RTEMS_BDBUF_STATE_READ_AHEAD: |
---|
| 1867 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
| 1868 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
| 1869 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
| 1870 | available = TRUE; |
---|
| 1871 | break; |
---|
| 1872 | |
---|
| 1873 | case RTEMS_BDBUF_STATE_SYNC: |
---|
| 1874 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
| 1875 | bd->waiters++; |
---|
| 1876 | rtems_bdbuf_wait (pool, &pool->transfer, &pool->transfer_waiters); |
---|
| 1877 | bd->waiters--; |
---|
| 1878 | break; |
---|
| 1879 | |
---|
| 1880 | default: |
---|
| 1881 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
[e51bd96] | 1882 | } |
---|
[3899a537] | 1883 | } |
---|
[048dcd2b] | 1884 | |
---|
[3899a537] | 1885 | rtems_bdbuf_unlock_pool (pool); |
---|
| 1886 | |
---|
| 1887 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 1888 | } |
---|
| 1889 | |
---|
[c21c850e] | 1890 | /** |
---|
| 1891 | * Synchronize all modified buffers for this device with the disk and wait |
---|
| 1892 | * until the transfers have completed. The sync mutex for the pool is locked |
---|
| 1893 | * stopping the addition of any further modifed buffers. It is only the |
---|
| 1894 | * currently modified buffers that are written. |
---|
[e51bd96] | 1895 | * |
---|
[c21c850e] | 1896 | * @param dev Block device number |
---|
[e51bd96] | 1897 | * |
---|
[c21c850e] | 1898 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 1899 | * successfully or error code if error is occured) |
---|
[e51bd96] | 1900 | */ |
---|
| 1901 | rtems_status_code |
---|
[3899a537] | 1902 | rtems_bdbuf_syncdev (dev_t dev) |
---|
[e51bd96] | 1903 | { |
---|
[3899a537] | 1904 | rtems_disk_device* dd; |
---|
| 1905 | rtems_bdbuf_pool* pool; |
---|
| 1906 | rtems_status_code sc; |
---|
| 1907 | rtems_event_set out; |
---|
[e51bd96] | 1908 | |
---|
[3899a537] | 1909 | #if RTEMS_BDBUF_TRACE |
---|
| 1910 | rtems_bdbuf_printf ("syncdev: %08x\n", dev); |
---|
| 1911 | #endif |
---|
[e51bd96] | 1912 | |
---|
[3899a537] | 1913 | /* |
---|
| 1914 | * Do not hold the pool lock when obtaining the disk table. |
---|
| 1915 | */ |
---|
| 1916 | dd = rtems_disk_obtain (dev); |
---|
| 1917 | if (dd == NULL) |
---|
| 1918 | return RTEMS_INVALID_ID; |
---|
| 1919 | |
---|
| 1920 | pool = rtems_bdbuf_get_pool (dd->pool); |
---|
| 1921 | |
---|
| 1922 | /* |
---|
| 1923 | * Take the sync lock before locking the pool. Once we have the sync lock |
---|
| 1924 | * we can lock the pool. If another thread has the sync lock it will cause |
---|
| 1925 | * this thread to block until it owns the sync lock then it can own the |
---|
| 1926 | * pool. The sync lock can only be obtained with the pool unlocked. |
---|
| 1927 | */ |
---|
| 1928 | |
---|
| 1929 | rtems_bdbuf_lock_sync (pool); |
---|
| 1930 | rtems_bdbuf_lock_pool (pool); |
---|
[e51bd96] | 1931 | |
---|
[c21c850e] | 1932 | /* |
---|
| 1933 | * Set the pool to have a sync active for a specific device and let the swap |
---|
| 1934 | * out task know the id of the requester to wake when done. |
---|
| 1935 | * |
---|
| 1936 | * The swap out task will negate the sync active flag when no more buffers |
---|
| 1937 | * for the device are held on the modified for sync queues. |
---|
| 1938 | */ |
---|
[3899a537] | 1939 | pool->sync_active = TRUE; |
---|
| 1940 | pool->sync_requester = rtems_task_self (); |
---|
| 1941 | pool->sync_device = dev; |
---|
| 1942 | |
---|
| 1943 | rtems_bdbuf_wake_swapper (); |
---|
| 1944 | rtems_bdbuf_unlock_pool (pool); |
---|
| 1945 | |
---|
| 1946 | sc = rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
| 1947 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
| 1948 | 0, &out); |
---|
[e51bd96] | 1949 | |
---|
[3899a537] | 1950 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 1951 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
| 1952 | |
---|
| 1953 | rtems_bdbuf_unlock_sync (pool); |
---|
| 1954 | |
---|
| 1955 | return rtems_disk_release(dd); |
---|
[e51bd96] | 1956 | } |
---|
| 1957 | |
---|
[c21c850e] | 1958 | /** |
---|
| 1959 | * Call back handler called by the low level driver when the transfer has |
---|
| 1960 | * completed. This function may be invoked from interrupt handler. |
---|
[e51bd96] | 1961 | * |
---|
[c21c850e] | 1962 | * @param arg Arbitrary argument specified in block device request |
---|
| 1963 | * structure (in this case - pointer to the appropriate |
---|
| 1964 | * block device request structure). |
---|
| 1965 | * @param status I/O completion status |
---|
| 1966 | * @param error errno error code if status != RTEMS_SUCCESSFUL |
---|
[e51bd96] | 1967 | */ |
---|
[3899a537] | 1968 | static void |
---|
| 1969 | rtems_bdbuf_write_done(void *arg, rtems_status_code status, int error) |
---|
| 1970 | { |
---|
| 1971 | rtems_blkdev_request* req = (rtems_blkdev_request*) arg; |
---|
| 1972 | |
---|
| 1973 | req->error = error; |
---|
| 1974 | req->status = status; |
---|
| 1975 | |
---|
| 1976 | rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
| 1977 | } |
---|
| 1978 | |
---|
| 1979 | /** |
---|
[c21c850e] | 1980 | * Process the modified list of buffers. There us a sync or modified list that |
---|
| 1981 | * needs to be handled. |
---|
| 1982 | * |
---|
| 1983 | * @param pid The pool id to process modified buffers on. |
---|
| 1984 | * @param dev The device to handle. If -1 no device is selected so select the |
---|
| 1985 | * device of the first buffer to be written to disk. |
---|
| 1986 | * @param chain The modified chain to process. |
---|
| 1987 | * @param transfer The chain to append buffers to be written too. |
---|
| 1988 | * @param sync_active If TRUE this is a sync operation so expire all timers. |
---|
| 1989 | * @param update_timers If TRUE update the timers. |
---|
| 1990 | * @param timer_delta It update_timers is TRUE update the timers by this |
---|
| 1991 | * amount. |
---|
[3899a537] | 1992 | */ |
---|
| 1993 | static void |
---|
| 1994 | rtems_bdbuf_swapout_modified_processing (rtems_bdpool_id pid, |
---|
| 1995 | dev_t* dev, |
---|
| 1996 | rtems_chain_control* chain, |
---|
| 1997 | rtems_chain_control* transfer, |
---|
| 1998 | boolean sync_active, |
---|
| 1999 | boolean update_timers, |
---|
| 2000 | uint32_t timer_delta) |
---|
[e51bd96] | 2001 | { |
---|
[3899a537] | 2002 | if (!rtems_chain_is_empty (chain)) |
---|
| 2003 | { |
---|
| 2004 | rtems_chain_node* node = rtems_chain_head (chain); |
---|
| 2005 | node = node->next; |
---|
| 2006 | |
---|
| 2007 | while (!rtems_chain_is_tail (chain, node)) |
---|
| 2008 | { |
---|
| 2009 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
| 2010 | |
---|
| 2011 | if (bd->pool == pid) |
---|
| 2012 | { |
---|
| 2013 | /* |
---|
[c21c850e] | 2014 | * Check if the buffer's hold timer has reached 0. If a sync is active |
---|
| 2015 | * force all the timers to 0. |
---|
[3899a537] | 2016 | * |
---|
[c21c850e] | 2017 | * @note Lots of sync requests will skew this timer. It should be based |
---|
| 2018 | * on TOD to be accurate. Does it matter ? |
---|
[3899a537] | 2019 | */ |
---|
| 2020 | if (sync_active) |
---|
| 2021 | bd->hold_timer = 0; |
---|
| 2022 | |
---|
| 2023 | if (bd->hold_timer) |
---|
| 2024 | { |
---|
| 2025 | if (update_timers) |
---|
| 2026 | { |
---|
| 2027 | if (bd->hold_timer > timer_delta) |
---|
| 2028 | bd->hold_timer -= timer_delta; |
---|
| 2029 | else |
---|
| 2030 | bd->hold_timer = 0; |
---|
| 2031 | } |
---|
| 2032 | |
---|
| 2033 | if (bd->hold_timer) |
---|
| 2034 | { |
---|
| 2035 | node = node->next; |
---|
| 2036 | continue; |
---|
| 2037 | } |
---|
| 2038 | } |
---|
| 2039 | |
---|
| 2040 | /* |
---|
| 2041 | * This assumes we can set dev_t to -1 which is just an |
---|
[c21c850e] | 2042 | * assumption. Cannot use the transfer list being empty the sync dev |
---|
| 2043 | * calls sets the dev to use. |
---|
[3899a537] | 2044 | */ |
---|
| 2045 | if (*dev == -1) |
---|
| 2046 | *dev = bd->dev; |
---|
| 2047 | |
---|
| 2048 | if (bd->dev == *dev) |
---|
| 2049 | { |
---|
| 2050 | rtems_chain_node* next_node = node->next; |
---|
| 2051 | rtems_chain_extract (node); |
---|
| 2052 | rtems_chain_append (transfer, node); |
---|
| 2053 | node = next_node; |
---|
| 2054 | bd->state = RTEMS_BDBUF_STATE_TRANSFER; |
---|
| 2055 | } |
---|
| 2056 | else |
---|
| 2057 | { |
---|
| 2058 | node = node->next; |
---|
| 2059 | } |
---|
| 2060 | } |
---|
| 2061 | } |
---|
| 2062 | } |
---|
| 2063 | } |
---|
[048dcd2b] | 2064 | |
---|
[3899a537] | 2065 | /** |
---|
[c21c850e] | 2066 | * Process a pool's modified buffers. Check the sync list first then the |
---|
| 2067 | * modified list extracting the buffers suitable to be written to disk. We have |
---|
| 2068 | * a device at a time. The task level loop will repeat this operation while |
---|
| 2069 | * there are buffers to be written. If the transfer fails place the buffers |
---|
| 2070 | * back on the modified list and try again later. The pool is unlocked while |
---|
| 2071 | * the buffers are beign written to disk. |
---|
| 2072 | * |
---|
| 2073 | * @param pid The pool id to process modified buffers on. |
---|
| 2074 | * @param timer_delta It update_timers is TRUE update the timers by this |
---|
| 2075 | * amount. |
---|
| 2076 | * @param update_timers If TRUE update the timers. |
---|
| 2077 | * @param write_req The write request structure. There is only one. |
---|
| 2078 | * |
---|
| 2079 | * @retval TRUE Buffers where written to disk so scan again. |
---|
| 2080 | * @retval FALSE No buffers where written to disk. |
---|
[3899a537] | 2081 | */ |
---|
| 2082 | static boolean |
---|
| 2083 | rtems_bdbuf_swapout_pool_processing (rtems_bdpool_id pid, |
---|
| 2084 | unsigned long timer_delta, |
---|
| 2085 | boolean update_timers, |
---|
| 2086 | rtems_blkdev_request* write_req) |
---|
| 2087 | { |
---|
| 2088 | rtems_bdbuf_pool* pool = rtems_bdbuf_get_pool (pid); |
---|
| 2089 | rtems_chain_control transfer; |
---|
| 2090 | dev_t dev = -1; |
---|
| 2091 | rtems_disk_device* dd; |
---|
[c21c850e] | 2092 | boolean transfered_buffers = TRUE; |
---|
[048dcd2b] | 2093 | |
---|
[3899a537] | 2094 | rtems_chain_initialize_empty (&transfer); |
---|
| 2095 | |
---|
| 2096 | rtems_bdbuf_lock_pool (pool); |
---|
| 2097 | |
---|
[c21c850e] | 2098 | /* |
---|
| 2099 | * When the sync is for a device limit the sync to that device. If the sync |
---|
| 2100 | * is for a buffer handle the devices in the order on the sync list. This |
---|
| 2101 | * means the dev is -1. |
---|
| 2102 | */ |
---|
[3899a537] | 2103 | if (pool->sync_active) |
---|
| 2104 | dev = pool->sync_device; |
---|
| 2105 | |
---|
| 2106 | /* |
---|
[c21c850e] | 2107 | * If we have any buffers in the sync queue move then to the modified |
---|
| 2108 | * list. The first sync buffer will select the device we use. |
---|
[3899a537] | 2109 | */ |
---|
| 2110 | rtems_bdbuf_swapout_modified_processing (pid, &dev, |
---|
| 2111 | &pool->sync, &transfer, |
---|
| 2112 | TRUE, FALSE, |
---|
| 2113 | timer_delta); |
---|
| 2114 | |
---|
| 2115 | /* |
---|
| 2116 | * Process the pool's modified list. |
---|
| 2117 | */ |
---|
| 2118 | rtems_bdbuf_swapout_modified_processing (pid, &dev, |
---|
| 2119 | &pool->modified, &transfer, |
---|
| 2120 | pool->sync_active, |
---|
| 2121 | update_timers, |
---|
| 2122 | timer_delta); |
---|
| 2123 | |
---|
| 2124 | /* |
---|
| 2125 | * We have all the buffers that have been modified for this device so |
---|
| 2126 | * the pool can be unlocked because the state is set to TRANSFER. |
---|
| 2127 | */ |
---|
[c21c850e] | 2128 | |
---|
[3899a537] | 2129 | rtems_bdbuf_unlock_pool (pool); |
---|
| 2130 | |
---|
| 2131 | /* |
---|
| 2132 | * If there are buffers to transfer to the media tranfer them. |
---|
| 2133 | */ |
---|
| 2134 | if (rtems_chain_is_empty (&transfer)) |
---|
[c21c850e] | 2135 | transfered_buffers = FALSE; |
---|
[3899a537] | 2136 | else |
---|
| 2137 | { |
---|
| 2138 | /* |
---|
| 2139 | * Obtain the disk device. Release the pool mutex to avoid a dead |
---|
| 2140 | * lock. |
---|
| 2141 | */ |
---|
| 2142 | dd = rtems_disk_obtain (dev); |
---|
[e51bd96] | 2143 | if (dd == NULL) |
---|
[c21c850e] | 2144 | transfered_buffers = FALSE; |
---|
[3899a537] | 2145 | else |
---|
| 2146 | { |
---|
| 2147 | /* |
---|
| 2148 | * The last block number used when the driver only supports |
---|
| 2149 | * continuous blocks in a single request. |
---|
| 2150 | */ |
---|
| 2151 | uint32_t last_block = 0; |
---|
| 2152 | |
---|
| 2153 | /* |
---|
[c21c850e] | 2154 | * Take as many buffers as configured and pass to the driver. Note, the |
---|
| 2155 | * API to the drivers has the array of buffers and if a chain was passed |
---|
| 2156 | * we could have just passed the list. If the driver API is updated it |
---|
| 2157 | * should be possible to make this change with little effect in this |
---|
| 2158 | * code. The array that is passed is broken in design and should be |
---|
| 2159 | * removed. Merging to members of a struct into the first member is |
---|
| 2160 | * trouble waiting to happen. |
---|
[3899a537] | 2161 | */ |
---|
| 2162 | |
---|
| 2163 | write_req->status = RTEMS_RESOURCE_IN_USE; |
---|
| 2164 | write_req->start = dd->start; |
---|
| 2165 | write_req->error = 0; |
---|
| 2166 | write_req->count = 0; |
---|
| 2167 | write_req->bufnum = 0; |
---|
| 2168 | |
---|
| 2169 | while (!rtems_chain_is_empty (&transfer)) |
---|
| 2170 | { |
---|
| 2171 | rtems_bdbuf_buffer* bd = |
---|
| 2172 | (rtems_bdbuf_buffer*) rtems_chain_get (&transfer); |
---|
| 2173 | |
---|
| 2174 | boolean write = FALSE; |
---|
| 2175 | |
---|
| 2176 | /* |
---|
[c21c850e] | 2177 | * If the device only accepts sequential buffers and this is not the |
---|
| 2178 | * first buffer (the first is always sequential, and the buffer is not |
---|
| 2179 | * sequential then put the buffer back on the transfer chain and write |
---|
| 2180 | * the committed buffers. |
---|
[3899a537] | 2181 | */ |
---|
| 2182 | |
---|
| 2183 | if ((dd->capabilities & RTEMS_BLKDEV_CAP_MULTISECTOR_CONT) && |
---|
| 2184 | write_req->count && |
---|
| 2185 | (bd->block != (last_block + 1))) |
---|
| 2186 | { |
---|
| 2187 | rtems_chain_prepend (&transfer, &bd->link); |
---|
| 2188 | write = TRUE; |
---|
| 2189 | } |
---|
| 2190 | else |
---|
| 2191 | { |
---|
| 2192 | write_req->bufs[write_req->count].user = bd; |
---|
| 2193 | write_req->bufs[write_req->count].block = bd->block; |
---|
| 2194 | write_req->bufs[write_req->count].length = dd->block_size; |
---|
| 2195 | write_req->bufs[write_req->count].buffer = bd->buffer; |
---|
| 2196 | write_req->count++; |
---|
| 2197 | write_req->bufnum++; |
---|
| 2198 | last_block = bd->block; |
---|
| 2199 | } |
---|
| 2200 | |
---|
| 2201 | /* |
---|
[c21c850e] | 2202 | * Perform the transfer if there are no more buffers, or the transfer |
---|
| 2203 | * size has reached the configured max. value. |
---|
[3899a537] | 2204 | */ |
---|
[048dcd2b] | 2205 | |
---|
[3899a537] | 2206 | if (rtems_chain_is_empty (&transfer) || |
---|
| 2207 | (write_req->count >= rtems_bdbuf_configuration.max_write_blocks)) |
---|
| 2208 | write = TRUE; |
---|
[048dcd2b] | 2209 | |
---|
[3899a537] | 2210 | if (write) |
---|
[e51bd96] | 2211 | { |
---|
[3899a537] | 2212 | int result; |
---|
| 2213 | int b; |
---|
| 2214 | |
---|
| 2215 | /* |
---|
[c21c850e] | 2216 | * Perform the transfer. No pool locks, no preemption, only the disk |
---|
| 2217 | * device is being held. |
---|
[3899a537] | 2218 | */ |
---|
| 2219 | result = dd->ioctl (dd->phys_dev->dev, |
---|
| 2220 | RTEMS_BLKIO_REQUEST, write_req); |
---|
| 2221 | |
---|
| 2222 | if (result < 0) |
---|
| 2223 | { |
---|
| 2224 | rtems_bdbuf_lock_pool (pool); |
---|
| 2225 | |
---|
| 2226 | for (b = 0; b < write_req->count; b++) |
---|
| 2227 | { |
---|
| 2228 | bd = write_req->bufs[b].user; |
---|
| 2229 | bd->state = RTEMS_BDBUF_STATE_MODIFIED; |
---|
| 2230 | bd->error = errno; |
---|
| 2231 | |
---|
| 2232 | /* |
---|
| 2233 | * Place back on the pools modified queue and try again. |
---|
| 2234 | * |
---|
[c21c850e] | 2235 | * @warning Not sure this is the best option but I do not know |
---|
| 2236 | * what else can be done. |
---|
[3899a537] | 2237 | */ |
---|
| 2238 | rtems_chain_append (&pool->modified, &bd->link); |
---|
| 2239 | } |
---|
| 2240 | } |
---|
| 2241 | else |
---|
| 2242 | { |
---|
| 2243 | rtems_status_code sc = 0; |
---|
| 2244 | rtems_event_set out; |
---|
| 2245 | |
---|
| 2246 | sc = rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
| 2247 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
| 2248 | 0, &out); |
---|
| 2249 | |
---|
| 2250 | if (sc != RTEMS_SUCCESSFUL) |
---|
| 2251 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
| 2252 | |
---|
| 2253 | rtems_bdbuf_lock_pool (pool); |
---|
| 2254 | |
---|
| 2255 | for (b = 0; b < write_req->count; b++) |
---|
| 2256 | { |
---|
| 2257 | bd = write_req->bufs[b].user; |
---|
| 2258 | bd->state = RTEMS_BDBUF_STATE_CACHED; |
---|
| 2259 | bd->error = 0; |
---|
| 2260 | |
---|
| 2261 | rtems_chain_append (&pool->lru, &bd->link); |
---|
| 2262 | |
---|
| 2263 | if (bd->waiters) |
---|
| 2264 | rtems_bdbuf_wake (pool->transfer, &pool->transfer_waiters); |
---|
| 2265 | else |
---|
| 2266 | { |
---|
| 2267 | if (rtems_chain_has_only_one_node (&pool->lru)) |
---|
| 2268 | rtems_bdbuf_wake (pool->waiting, &pool->wait_waiters); |
---|
| 2269 | } |
---|
| 2270 | } |
---|
| 2271 | } |
---|
| 2272 | |
---|
| 2273 | rtems_bdbuf_unlock_pool (pool); |
---|
| 2274 | |
---|
| 2275 | write_req->status = RTEMS_RESOURCE_IN_USE; |
---|
| 2276 | write_req->error = 0; |
---|
| 2277 | write_req->count = 0; |
---|
| 2278 | write_req->bufnum = 0; |
---|
[e51bd96] | 2279 | } |
---|
[3899a537] | 2280 | } |
---|
| 2281 | |
---|
| 2282 | rtems_disk_release (dd); |
---|
| 2283 | } |
---|
| 2284 | } |
---|
| 2285 | |
---|
[c21c850e] | 2286 | if (pool->sync_active && ! transfered_buffers) |
---|
| 2287 | { |
---|
| 2288 | rtems_id sync_requester = pool->sync_requester; |
---|
| 2289 | pool->sync_active = FALSE; |
---|
| 2290 | pool->sync_requester = 0; |
---|
| 2291 | if (sync_requester) |
---|
| 2292 | rtems_event_send (sync_requester, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
| 2293 | } |
---|
[3899a537] | 2294 | |
---|
[c21c850e] | 2295 | return transfered_buffers; |
---|
[e51bd96] | 2296 | } |
---|
| 2297 | |
---|
[3899a537] | 2298 | /** |
---|
[c21c850e] | 2299 | * Body of task which takes care on flushing modified buffers to the disk. |
---|
| 2300 | * |
---|
| 2301 | * @param arg The task argument which is the context. |
---|
[e51bd96] | 2302 | */ |
---|
[8b96149] | 2303 | static rtems_task |
---|
[3899a537] | 2304 | rtems_bdbuf_swapout_task (rtems_task_argument arg) |
---|
[e51bd96] | 2305 | { |
---|
[3899a537] | 2306 | rtems_bdbuf_context* context = (rtems_bdbuf_context*) arg; |
---|
| 2307 | rtems_blkdev_request* write_req; |
---|
| 2308 | uint32_t period_in_ticks; |
---|
| 2309 | const uint32_t period_in_msecs = rtems_bdbuf_configuration.swapout_period; |
---|
| 2310 | uint32_t timer_delta; |
---|
| 2311 | rtems_status_code sc; |
---|
| 2312 | |
---|
| 2313 | /* |
---|
| 2314 | * @note chrisj The rtems_blkdev_request and the array at the end is a hack. |
---|
| 2315 | * I am disappointment at finding code like this in RTEMS. The request should |
---|
| 2316 | * have been a rtems_chain_control. Simple, fast and less storage as the node |
---|
| 2317 | * is already part of the buffer structure. |
---|
| 2318 | */ |
---|
| 2319 | write_req = |
---|
| 2320 | malloc (sizeof (rtems_blkdev_request) + |
---|
| 2321 | (rtems_bdbuf_configuration.max_write_blocks * |
---|
| 2322 | sizeof (rtems_blkdev_sg_buffer))); |
---|
| 2323 | |
---|
| 2324 | if (!write_req) |
---|
| 2325 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM); |
---|
| 2326 | |
---|
| 2327 | write_req->req = RTEMS_BLKDEV_REQ_WRITE; |
---|
| 2328 | write_req->req_done = rtems_bdbuf_write_done; |
---|
| 2329 | write_req->done_arg = write_req; |
---|
| 2330 | write_req->io_task = rtems_task_self (); |
---|
| 2331 | |
---|
| 2332 | period_in_ticks = TOD_MICROSECONDS_TO_TICKS (period_in_msecs * 1000); |
---|
| 2333 | |
---|
| 2334 | /* |
---|
[c21c850e] | 2335 | * This is temporary. Needs to be changed to use the real time clock. |
---|
[3899a537] | 2336 | */ |
---|
| 2337 | timer_delta = period_in_msecs; |
---|
| 2338 | |
---|
| 2339 | while (context->swapout_enabled) |
---|
| 2340 | { |
---|
| 2341 | rtems_event_set out; |
---|
[e51bd96] | 2342 | |
---|
[0ebfac19] | 2343 | /* |
---|
[3899a537] | 2344 | * Only update the timers once in the processing cycle. |
---|
| 2345 | */ |
---|
| 2346 | boolean update_timers = TRUE; |
---|
| 2347 | |
---|
| 2348 | /* |
---|
[c21c850e] | 2349 | * If we write buffers to any disk perform a check again. We only write a |
---|
| 2350 | * single device at a time and a pool may have more than one devices |
---|
| 2351 | * buffers modified waiting to be written. |
---|
[0ebfac19] | 2352 | */ |
---|
[3899a537] | 2353 | boolean transfered_buffers; |
---|
| 2354 | |
---|
| 2355 | do |
---|
[e51bd96] | 2356 | { |
---|
[3899a537] | 2357 | rtems_bdpool_id pid; |
---|
| 2358 | |
---|
| 2359 | transfered_buffers = FALSE; |
---|
| 2360 | |
---|
| 2361 | /* |
---|
| 2362 | * Loop over each pool extacting all the buffers we find for a specific |
---|
| 2363 | * device. The device is the first one we find on a modified list of a |
---|
| 2364 | * pool. Process the sync queue of buffers first. |
---|
| 2365 | */ |
---|
| 2366 | for (pid = 0; pid < context->npools; pid++) |
---|
| 2367 | { |
---|
| 2368 | if (rtems_bdbuf_swapout_pool_processing (pid, |
---|
| 2369 | timer_delta, |
---|
| 2370 | update_timers, |
---|
| 2371 | write_req)) |
---|
| 2372 | { |
---|
| 2373 | transfered_buffers = TRUE; |
---|
[e51bd96] | 2374 | } |
---|
[3899a537] | 2375 | } |
---|
| 2376 | |
---|
| 2377 | /* |
---|
| 2378 | * Only update the timers once. |
---|
| 2379 | */ |
---|
| 2380 | update_timers = FALSE; |
---|
[e51bd96] | 2381 | } |
---|
[3899a537] | 2382 | while (transfered_buffers); |
---|
| 2383 | |
---|
| 2384 | sc = rtems_event_receive (RTEMS_BDBUF_SWAPOUT_SYNC, |
---|
| 2385 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
| 2386 | period_in_ticks, |
---|
| 2387 | &out); |
---|
| 2388 | |
---|
| 2389 | if ((sc != RTEMS_SUCCESSFUL) && (sc != RTEMS_TIMEOUT)) |
---|
| 2390 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
| 2391 | } |
---|
| 2392 | |
---|
| 2393 | free (write_req); |
---|
| 2394 | |
---|
| 2395 | rtems_task_delete (RTEMS_SELF); |
---|
[e51bd96] | 2396 | } |
---|
| 2397 | |
---|
[3899a537] | 2398 | /** |
---|
| 2399 | * Find first appropriate buffer pool. This primitive returns the index of |
---|
| 2400 | * first buffer pool which block size is greater than or equal to specified |
---|
| 2401 | * size. |
---|
[e51bd96] | 2402 | * |
---|
[c21c850e] | 2403 | * @param block_size Requested block size |
---|
| 2404 | * @param pool The pool to use for the requested pool size. |
---|
[e51bd96] | 2405 | * |
---|
[c21c850e] | 2406 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 2407 | * successfully or error code if error is occured) |
---|
| 2408 | * @retval RTEMS_INVALID_SIZE The specified block size is invalid (not a power |
---|
| 2409 | * of 2) |
---|
| 2410 | * @retval RTEMS_NOT_DEFINED The buffer pool for this or greater block size |
---|
| 2411 | * is not configured. |
---|
[e51bd96] | 2412 | */ |
---|
| 2413 | rtems_status_code |
---|
[3899a537] | 2414 | rtems_bdbuf_find_pool (int block_size, rtems_bdpool_id *pool) |
---|
[e51bd96] | 2415 | { |
---|
[3899a537] | 2416 | rtems_bdbuf_pool* p; |
---|
| 2417 | rtems_bdpool_id i; |
---|
| 2418 | rtems_bdpool_id curid = -1; |
---|
| 2419 | rtems_boolean found = FALSE; |
---|
| 2420 | int cursize = INT_MAX; |
---|
| 2421 | int j; |
---|
| 2422 | |
---|
| 2423 | for (j = block_size; (j != 0) && ((j & 1) == 0); j >>= 1); |
---|
| 2424 | if (j != 1) |
---|
| 2425 | return RTEMS_INVALID_SIZE; |
---|
| 2426 | |
---|
| 2427 | for (i = 0; i < rtems_bdbuf_ctx.npools; i++) |
---|
| 2428 | { |
---|
| 2429 | p = rtems_bdbuf_get_pool (i); |
---|
| 2430 | if ((p->blksize >= block_size) && |
---|
| 2431 | (p->blksize < cursize)) |
---|
[e51bd96] | 2432 | { |
---|
[3899a537] | 2433 | curid = i; |
---|
| 2434 | cursize = p->blksize; |
---|
| 2435 | found = TRUE; |
---|
[e51bd96] | 2436 | } |
---|
[3899a537] | 2437 | } |
---|
[048dcd2b] | 2438 | |
---|
[3899a537] | 2439 | if (found) |
---|
| 2440 | { |
---|
| 2441 | if (pool != NULL) |
---|
| 2442 | *pool = curid; |
---|
| 2443 | return RTEMS_SUCCESSFUL; |
---|
| 2444 | } |
---|
| 2445 | else |
---|
| 2446 | { |
---|
| 2447 | return RTEMS_NOT_DEFINED; |
---|
| 2448 | } |
---|
[e51bd96] | 2449 | } |
---|
| 2450 | |
---|
[3899a537] | 2451 | /** |
---|
| 2452 | * Obtain characteristics of buffer pool with specified number. |
---|
[e51bd96] | 2453 | * |
---|
[c21c850e] | 2454 | * @param pool Buffer pool number |
---|
| 2455 | * @param block_size Block size for which buffer pool is configured returned |
---|
| 2456 | * there |
---|
| 2457 | * @param blocks Number of buffers in buffer pool. |
---|
[e51bd96] | 2458 | * |
---|
| 2459 | * RETURNS: |
---|
[c21c850e] | 2460 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
| 2461 | * successfully or error code if error is occured) |
---|
| 2462 | * @retval RTEMS_INVALID_SIZE The appropriate buffer pool is not configured. |
---|
[e51bd96] | 2463 | * |
---|
[c21c850e] | 2464 | * @note Buffer pools enumerated continuously starting from 0. |
---|
[e51bd96] | 2465 | */ |
---|
| 2466 | rtems_status_code |
---|
[c21c850e] | 2467 | rtems_bdbuf_get_pool_info (rtems_bdpool_id pool, int* block_size, int* blocks) |
---|
[e51bd96] | 2468 | { |
---|
[3899a537] | 2469 | if (pool >= rtems_bdbuf_ctx.npools) |
---|
| 2470 | return RTEMS_INVALID_NUMBER; |
---|
[048dcd2b] | 2471 | |
---|
[3899a537] | 2472 | if (block_size != NULL) |
---|
| 2473 | { |
---|
| 2474 | *block_size = rtems_bdbuf_ctx.pool[pool].blksize; |
---|
| 2475 | } |
---|
[048dcd2b] | 2476 | |
---|
[3899a537] | 2477 | if (blocks != NULL) |
---|
| 2478 | { |
---|
| 2479 | *blocks = rtems_bdbuf_ctx.pool[pool].nblks; |
---|
| 2480 | } |
---|
[048dcd2b] | 2481 | |
---|
[3899a537] | 2482 | return RTEMS_SUCCESSFUL; |
---|
[e51bd96] | 2483 | } |
---|