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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8 | * Alexander Kukuta <kam@oktet.ru> |
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9 | * |
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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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14 | * @(#) bdbuf.c,v 1.14 2004/04/17 08:15:17 ralf Exp |
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15 | */ |
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16 | |
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17 | /** |
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18 | * @file |
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19 | * |
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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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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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26 | * |
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27 | * read/read ahead |
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28 | * +-------------------------------+ |
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29 | * | v |
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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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46 | * +-----------+ |
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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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58 | * |
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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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71 | * |
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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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83 | * |
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84 | * The pool have the following lists of buffers: |
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85 | * |
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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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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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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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101 | #include <rtems.h> |
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102 | #include <rtems/error.h> |
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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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107 | #if RTEMS_BDBUF_TRACE |
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108 | #include <stdio.h> |
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109 | #endif |
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110 | |
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111 | #include "rtems/bdbuf.h" |
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112 | |
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113 | /** |
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114 | * The BD buffer context. |
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115 | */ |
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116 | typedef struct rtems_bdbuf_context { |
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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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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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125 | */ |
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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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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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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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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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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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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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157 | * |
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158 | * @warning Priority inheritance is on. |
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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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163 | |
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164 | /** |
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165 | * Waiter semaphore attributes. |
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166 | * |
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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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171 | */ |
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172 | #define RTEMS_BDBUF_POOL_WAITER_ATTRIBS \ |
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173 | (RTEMS_PRIORITY | RTEMS_SIMPLE_BINARY_SEMAPHORE | \ |
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174 | RTEMS_NO_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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175 | |
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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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180 | |
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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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185 | |
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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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207 | #endif |
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208 | |
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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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216 | #endif |
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217 | |
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218 | /** |
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219 | * Searches for the node with specified dev/block. |
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220 | * |
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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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226 | */ |
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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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231 | { |
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232 | rtems_bdbuf_buffer* p = *root; |
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233 | |
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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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237 | { |
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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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243 | } |
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244 | } |
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245 | |
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246 | return p; |
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247 | } |
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248 | |
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249 | /** |
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250 | * Inserts the specified node to the AVl-Tree. |
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251 | * |
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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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256 | */ |
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257 | static int |
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258 | rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root, |
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259 | rtems_bdbuf_buffer* node) |
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260 | { |
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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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281 | |
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282 | while (p != NULL) |
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283 | { |
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284 | *buf_prev++ = p; |
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285 | |
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286 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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287 | { |
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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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296 | } |
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297 | else if ((p->dev != dev) || (p->block != block)) |
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298 | { |
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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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311 | } |
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312 | |
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313 | p = q; |
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314 | } |
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315 | |
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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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320 | |
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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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425 | |
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426 | return 0; |
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427 | } |
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428 | |
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429 | |
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430 | /** |
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431 | * Removes the node from the tree. |
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432 | * |
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433 | * @param root_addr Pointer to pointer to the root node |
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434 | * @param node Pointer to the node to remove |
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435 | * @retval 0 Item removed |
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436 | * @retval -1 No such item found |
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437 | */ |
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438 | static int |
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439 | rtems_bdbuf_avl_remove(rtems_bdbuf_buffer** root, |
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440 | const rtems_bdbuf_buffer* node) |
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441 | { |
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442 | dev_t dev = node->dev; |
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443 | rtems_blkdev_bnum block = node->block; |
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444 | |
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445 | rtems_bdbuf_buffer* p = *root; |
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446 | rtems_bdbuf_buffer* q; |
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447 | rtems_bdbuf_buffer* r; |
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448 | rtems_bdbuf_buffer* s; |
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449 | rtems_bdbuf_buffer* p1; |
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450 | rtems_bdbuf_buffer* p2; |
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451 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
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452 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
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453 | |
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454 | boolean modified = FALSE; |
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455 | |
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456 | memset (buf_stack, 0, sizeof(buf_stack)); |
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457 | |
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458 | while (p != NULL) |
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459 | { |
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460 | *buf_prev++ = p; |
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461 | |
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462 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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463 | { |
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464 | p->avl.cache = 1; |
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465 | p = p->avl.right; |
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466 | } |
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467 | else if ((p->dev != dev) || (p->block != block)) |
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468 | { |
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469 | p->avl.cache = -1; |
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470 | p = p->avl.left; |
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471 | } |
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472 | else |
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473 | { |
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474 | /* node found */ |
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475 | break; |
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476 | } |
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477 | } |
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478 | |
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479 | if (p == NULL) |
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480 | { |
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481 | /* there is no such node */ |
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482 | return -1; |
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483 | } |
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484 | |
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485 | q = p; |
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486 | |
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487 | buf_prev--; |
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488 | if (buf_prev > buf_stack) |
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489 | { |
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490 | p = *(buf_prev - 1); |
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491 | } |
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492 | else |
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493 | { |
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494 | p = NULL; |
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495 | } |
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496 | |
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497 | /* at this moment q - is a node to delete, p is q's parent */ |
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498 | if (q->avl.right == NULL) |
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499 | { |
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500 | r = q->avl.left; |
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501 | if (r != NULL) |
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502 | { |
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503 | r->avl.bal = 0; |
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504 | } |
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505 | q = r; |
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506 | } |
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507 | else |
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508 | { |
---|
509 | rtems_bdbuf_buffer **t; |
---|
510 | |
---|
511 | r = q->avl.right; |
---|
512 | |
---|
513 | if (r->avl.left == NULL) |
---|
514 | { |
---|
515 | r->avl.left = q->avl.left; |
---|
516 | r->avl.bal = q->avl.bal; |
---|
517 | r->avl.cache = 1; |
---|
518 | *buf_prev++ = q = r; |
---|
519 | } |
---|
520 | else |
---|
521 | { |
---|
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; |
---|
539 | } |
---|
540 | } |
---|
541 | |
---|
542 | if (p != NULL) |
---|
543 | { |
---|
544 | if (p->avl.cache == -1) |
---|
545 | { |
---|
546 | p->avl.left = q; |
---|
547 | } |
---|
548 | else |
---|
549 | { |
---|
550 | p->avl.right = q; |
---|
551 | } |
---|
552 | } |
---|
553 | else |
---|
554 | { |
---|
555 | *root = q; |
---|
556 | } |
---|
557 | |
---|
558 | modified = TRUE; |
---|
559 | |
---|
560 | while (modified) |
---|
561 | { |
---|
562 | if (buf_prev > buf_stack) |
---|
563 | { |
---|
564 | p = *--buf_prev; |
---|
565 | } |
---|
566 | else |
---|
567 | { |
---|
568 | break; |
---|
569 | } |
---|
570 | |
---|
571 | if (p->avl.cache == -1) |
---|
572 | { |
---|
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) |
---|
593 | { |
---|
594 | p1->avl.bal = -1; |
---|
595 | modified = FALSE; |
---|
596 | } |
---|
597 | else |
---|
598 | { |
---|
599 | p->avl.bal = 0; |
---|
600 | p1->avl.bal = 0; |
---|
601 | } |
---|
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) |
---|
647 | { |
---|
648 | p1->avl.bal = 1; |
---|
649 | modified = FALSE; |
---|
650 | } |
---|
651 | else |
---|
652 | { |
---|
653 | p->avl.bal = 0; |
---|
654 | p1->avl.bal = 0; |
---|
655 | } |
---|
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 | } |
---|
679 | |
---|
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; |
---|
697 | } |
---|
698 | |
---|
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 | /** |
---|
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. |
---|
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 | * |
---|
783 | * The function assumes the pool is locked on entry and it will be locked on |
---|
784 | * exit. |
---|
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 |
---|
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 |
---|
872 | * hold the sync lock. The sync lock is used to block writes while a sync is |
---|
873 | * active. |
---|
874 | * |
---|
875 | * @param pool The pool the bd belongs to. |
---|
876 | * @param bd The bd to queue to the pool's modified list. |
---|
877 | */ |
---|
878 | static void |
---|
879 | rtems_bdbuf_append_modified (rtems_bdbuf_pool* pool, rtems_bdbuf_buffer* bd) |
---|
880 | { |
---|
881 | /* |
---|
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 |
---|
887 | */ |
---|
888 | if (pool->sync_active && (pool->sync_device == bd->dev)) |
---|
889 | { |
---|
890 | rtems_bdbuf_unlock_pool (pool); |
---|
891 | rtems_bdbuf_lock_sync (pool); |
---|
892 | rtems_bdbuf_unlock_sync (pool); |
---|
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 | |
---|
901 | /** |
---|
902 | * Wait the swapper task. |
---|
903 | */ |
---|
904 | static void |
---|
905 | rtems_bdbuf_wake_swapper (void) |
---|
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); |
---|
911 | } |
---|
912 | |
---|
913 | /** |
---|
914 | * Initialize single buffer pool. |
---|
915 | * |
---|
916 | * @param config Buffer pool configuration |
---|
917 | * @param pid Pool number |
---|
918 | * |
---|
919 | * @return RTEMS_SUCCESSFUL, if buffer pool initialized successfully, or error |
---|
920 | * code if error occured. |
---|
921 | */ |
---|
922 | static rtems_status_code |
---|
923 | rtems_bdbuf_initialize_pool (rtems_bdbuf_pool_config* config, |
---|
924 | rtems_bdpool_id pid) |
---|
925 | { |
---|
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; |
---|
931 | |
---|
932 | pool = rtems_bdbuf_get_pool (pid); |
---|
933 | |
---|
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; |
---|
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 | |
---|
948 | pool->access = 0; |
---|
949 | pool->access_waiters = 0; |
---|
950 | pool->transfer = 0; |
---|
951 | pool->transfer_waiters = 0; |
---|
952 | pool->waiting = 0; |
---|
953 | pool->wait_waiters = 0; |
---|
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) |
---|
970 | { |
---|
971 | free (pool->bds); |
---|
972 | return RTEMS_NO_MEMORY; |
---|
973 | } |
---|
974 | } |
---|
975 | |
---|
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 | } |
---|
993 | |
---|
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 | } |
---|
1003 | |
---|
1004 | sc = rtems_semaphore_create (rtems_build_name ('B', 'P', '0' + pid, 'S'), |
---|
1005 | 1, RTEMS_BDBUF_POOL_LOCK_ATTRIBS, 0, |
---|
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 | } |
---|
1026 | |
---|
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; |
---|
1055 | } |
---|
1056 | |
---|
1057 | /** |
---|
1058 | * Free resources allocated for buffer pool with specified number. |
---|
1059 | * |
---|
1060 | * @param pid Buffer pool number |
---|
1061 | * |
---|
1062 | * @retval RTEMS_SUCCESSFUL |
---|
1063 | */ |
---|
1064 | static rtems_status_code |
---|
1065 | rtems_bdbuf_release_pool (rtems_bdpool_id pid) |
---|
1066 | { |
---|
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; |
---|
1080 | } |
---|
1081 | |
---|
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. |
---|
1088 | * |
---|
1089 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
1090 | * successfully or error code if error is occured) |
---|
1091 | */ |
---|
1092 | rtems_status_code |
---|
1093 | rtems_bdbuf_init (void) |
---|
1094 | { |
---|
1095 | rtems_bdpool_id p; |
---|
1096 | rtems_status_code sc; |
---|
1097 | |
---|
1098 | #if RTEMS_BDBUF_TRACE |
---|
1099 | rtems_bdbuf_printf ("init\n"); |
---|
1100 | #endif |
---|
1101 | |
---|
1102 | if (rtems_bdbuf_pool_configuration_size <= 0) |
---|
1103 | return RTEMS_INVALID_SIZE; |
---|
1104 | |
---|
1105 | if (rtems_bdbuf_ctx.npools) |
---|
1106 | return RTEMS_RESOURCE_IN_USE; |
---|
1107 | |
---|
1108 | rtems_bdbuf_ctx.npools = rtems_bdbuf_pool_configuration_size; |
---|
1109 | |
---|
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) |
---|
1126 | { |
---|
1127 | rtems_bdpool_id j; |
---|
1128 | for (j = 0; j < p - 1; j++) |
---|
1129 | rtems_bdbuf_release_pool (j); |
---|
1130 | return sc; |
---|
1131 | } |
---|
1132 | } |
---|
1133 | |
---|
1134 | /* |
---|
1135 | * Create and start swapout task |
---|
1136 | */ |
---|
1137 | |
---|
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 | } |
---|
1155 | |
---|
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 | } |
---|
1167 | |
---|
1168 | return RTEMS_SUCCESSFUL; |
---|
1169 | } |
---|
1170 | |
---|
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 |
---|
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. |
---|
1179 | * |
---|
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 |
---|
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 |
---|
1184 | * buffer taken first. A buffer taken from the LRU list is removed from the AVL |
---|
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. |
---|
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: |
---|
1200 | * |
---|
1201 | * # Cached. Not being accessed or part of a media transfer. |
---|
1202 | * # Access or modifed access. Is with an upper layer being accessed. |
---|
1203 | * # Transfer. Is with the driver and part of a media transfer. |
---|
1204 | * |
---|
1205 | * If cached we assign the new state, extract it from any list it maybe part of |
---|
1206 | * and return to the user. |
---|
1207 | * |
---|
1208 | * This function assumes the pool the buffer is being taken from is locked and |
---|
1209 | * it will make sure the pool is locked when it returns. The pool will be |
---|
1210 | * unlocked if the call could block. |
---|
1211 | * |
---|
1212 | * @param device The physical disk device |
---|
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 |
---|
1216 | * |
---|
1217 | * @return RTEMS status code ( if operation completed successfully or error |
---|
1218 | * code if error is occured) |
---|
1219 | */ |
---|
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) |
---|
1225 | { |
---|
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 |
---|
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 |
---|
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 |
---|
1238 | * AVL tree with the one we are after. |
---|
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); |
---|
1246 | |
---|
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 |
---|
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. |
---|
1256 | */ |
---|
1257 | if (!bd) |
---|
1258 | { |
---|
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 |
---|
1262 | * LRU list is empty there are no available buffers check the modified |
---|
1263 | * list. |
---|
1264 | */ |
---|
1265 | if (rtems_chain_is_empty (&pool->ready)) |
---|
1266 | { |
---|
1267 | /* |
---|
1268 | * No unsed or read-ahead buffers. |
---|
1269 | * |
---|
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. |
---|
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) |
---|
1283 | { |
---|
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); |
---|
1289 | } |
---|
1290 | else |
---|
1291 | { |
---|
1292 | /* |
---|
1293 | * If there are buffers on the modified list expire the hold timer |
---|
1294 | * and wake the swap out task then wait else just go and wait. |
---|
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)) |
---|
1304 | { |
---|
1305 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
1306 | bd->hold_timer = 0; |
---|
1307 | write_blocks++; |
---|
1308 | node = node->next; |
---|
1309 | } |
---|
1310 | |
---|
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); |
---|
1319 | } |
---|
1320 | } |
---|
1321 | else |
---|
1322 | { |
---|
1323 | bd = (rtems_bdbuf_buffer *) rtems_chain_get (&(pool->ready)); |
---|
1324 | |
---|
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) |
---|
1330 | { |
---|
1331 | if (rtems_bdbuf_avl_remove (&pool->tree, bd) != 0) |
---|
1332 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1333 | } |
---|
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 | } |
---|
1351 | } |
---|
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 | /* |
---|
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. |
---|
1365 | */ |
---|
1366 | available = FALSE; |
---|
1367 | while (!available) |
---|
1368 | { |
---|
1369 | switch (bd->state) |
---|
1370 | { |
---|
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); |
---|
1393 | } |
---|
1394 | } |
---|
1395 | |
---|
1396 | /* |
---|
1397 | * Buffer is linked to the LRU, modifed, or sync lists. Remove it from there. |
---|
1398 | */ |
---|
1399 | rtems_chain_extract (&bd->link); |
---|
1400 | |
---|
1401 | return bd; |
---|
1402 | } |
---|
1403 | |
---|
1404 | /** |
---|
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) |
---|
1427 | */ |
---|
1428 | rtems_status_code |
---|
1429 | rtems_bdbuf_get (dev_t device, |
---|
1430 | rtems_blkdev_bnum block, |
---|
1431 | rtems_bdbuf_buffer** bdp) |
---|
1432 | { |
---|
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; |
---|
1474 | } |
---|
1475 | |
---|
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. |
---|
1479 | * |
---|
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 |
---|
1485 | */ |
---|
1486 | static void |
---|
1487 | rtems_bdbuf_read_done (void* arg, rtems_status_code status, int error) |
---|
1488 | { |
---|
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); |
---|
1495 | } |
---|
1496 | |
---|
1497 | /** |
---|
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. |
---|
1515 | * |
---|
1516 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
1517 | * successfully or error code if error is occured) |
---|
1518 | */ |
---|
1519 | rtems_status_code |
---|
1520 | rtems_bdbuf_read (dev_t device, |
---|
1521 | rtems_blkdev_bnum block, |
---|
1522 | rtems_bdbuf_buffer** bdp) |
---|
1523 | { |
---|
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 | } |
---|
1557 | |
---|
1558 | req->count = 0; |
---|
1559 | req->bufnum = 0; |
---|
1560 | |
---|
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; |
---|
1572 | |
---|
1573 | pool = rtems_bdbuf_get_pool (dd->phys_dev->pool); |
---|
1574 | |
---|
1575 | rtems_bdbuf_lock_pool (pool); |
---|
1576 | |
---|
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); |
---|
1590 | |
---|
1591 | /* |
---|
1592 | * Read ahead buffer is in the cache or none available. Read what we |
---|
1593 | * can. |
---|
1594 | */ |
---|
1595 | if (!bd) |
---|
1596 | break; |
---|
1597 | |
---|
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; |
---|
1604 | |
---|
1605 | bd->state = RTEMS_BDBUF_STATE_TRANSFER; |
---|
1606 | bd->error = 0; |
---|
1607 | |
---|
1608 | /* |
---|
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. |
---|
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 | } |
---|
1623 | |
---|
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 | */ |
---|
1641 | int result; |
---|
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) |
---|
1661 | { |
---|
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); |
---|
1675 | } |
---|
1676 | |
---|
1677 | rtems_bdbuf_lock_pool (pool); |
---|
1678 | |
---|
1679 | for (b = 1; b < req->count; b++) |
---|
1680 | { |
---|
1681 | bd = req->bufs[b].user; |
---|
1682 | bd->error = req->error; |
---|
1683 | bd->state = RTEMS_BDBUF_STATE_READ_AHEAD; |
---|
1684 | rtems_bdbuf_release (bd); |
---|
1685 | } |
---|
1686 | |
---|
1687 | bd = req->bufs[0].user; |
---|
1688 | } |
---|
1689 | |
---|
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; |
---|
1697 | |
---|
1698 | rtems_bdbuf_unlock_pool (pool); |
---|
1699 | rtems_disk_release (dd); |
---|
1700 | |
---|
1701 | *bdp = bd; |
---|
1702 | |
---|
1703 | return RTEMS_SUCCESSFUL; |
---|
1704 | } |
---|
1705 | |
---|
1706 | /** |
---|
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. |
---|
1713 | * |
---|
1714 | * @param bd Reference to the buffer descriptor. |
---|
1715 | * |
---|
1716 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
1717 | * successfully or error code if error is occured) |
---|
1718 | */ |
---|
1719 | rtems_status_code |
---|
1720 | rtems_bdbuf_release (rtems_bdbuf_buffer* bd) |
---|
1721 | { |
---|
1722 | rtems_bdbuf_pool* pool; |
---|
1723 | |
---|
1724 | if (bd == NULL) |
---|
1725 | return RTEMS_INVALID_ADDRESS; |
---|
1726 | |
---|
1727 | pool = rtems_bdbuf_get_pool (bd->pool); |
---|
1728 | |
---|
1729 | rtems_bdbuf_lock_pool (pool); |
---|
1730 | |
---|
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 | /* |
---|
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. |
---|
1745 | */ |
---|
1746 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
1747 | rtems_chain_prepend (&pool->ready, &bd->link); |
---|
1748 | else |
---|
1749 | { |
---|
1750 | bd->state = RTEMS_BDBUF_STATE_CACHED; |
---|
1751 | rtems_chain_append (&pool->lru, &bd->link); |
---|
1752 | } |
---|
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); |
---|
1776 | |
---|
1777 | return RTEMS_SUCCESSFUL; |
---|
1778 | } |
---|
1779 | |
---|
1780 | /** |
---|
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. |
---|
1789 | * |
---|
1790 | * @param bd Reference to the buffer descriptor. |
---|
1791 | * |
---|
1792 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
1793 | * successfully or error code if error is occured) |
---|
1794 | */ |
---|
1795 | rtems_status_code |
---|
1796 | rtems_bdbuf_release_modified (rtems_bdbuf_buffer* bd) |
---|
1797 | { |
---|
1798 | rtems_bdbuf_pool* pool; |
---|
1799 | |
---|
1800 | if (bd == NULL) |
---|
1801 | return RTEMS_INVALID_ADDRESS; |
---|
1802 | |
---|
1803 | pool = rtems_bdbuf_get_pool (bd->pool); |
---|
1804 | |
---|
1805 | rtems_bdbuf_lock_pool (pool); |
---|
1806 | |
---|
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); |
---|
1814 | |
---|
1815 | if (bd->waiters) |
---|
1816 | rtems_bdbuf_wake (pool->access, &pool->access_waiters); |
---|
1817 | |
---|
1818 | rtems_bdbuf_unlock_pool (pool); |
---|
1819 | |
---|
1820 | return RTEMS_SUCCESSFUL; |
---|
1821 | } |
---|
1822 | |
---|
1823 | /** |
---|
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. |
---|
1828 | * |
---|
1829 | * @note This code does not lock the sync mutex and stop additions to the |
---|
1830 | * modified queue. |
---|
1831 | * |
---|
1832 | * @param bd Reference to the buffer descriptor. |
---|
1833 | * |
---|
1834 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
1835 | * successfully or error code if error is occured) |
---|
1836 | */ |
---|
1837 | rtems_status_code |
---|
1838 | rtems_bdbuf_sync (rtems_bdbuf_buffer* bd) |
---|
1839 | { |
---|
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; |
---|
1855 | |
---|
1856 | rtems_chain_append (&pool->sync, &bd->link); |
---|
1857 | |
---|
1858 | rtems_bdbuf_wake_swapper (); |
---|
1859 | |
---|
1860 | available = FALSE; |
---|
1861 | while (!available) |
---|
1862 | { |
---|
1863 | switch (bd->state) |
---|
1864 | { |
---|
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); |
---|
1882 | } |
---|
1883 | } |
---|
1884 | |
---|
1885 | rtems_bdbuf_unlock_pool (pool); |
---|
1886 | |
---|
1887 | return RTEMS_SUCCESSFUL; |
---|
1888 | } |
---|
1889 | |
---|
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. |
---|
1895 | * |
---|
1896 | * @param dev Block device number |
---|
1897 | * |
---|
1898 | * @return RTEMS status code (RTEMS_SUCCESSFUL if operation completed |
---|
1899 | * successfully or error code if error is occured) |
---|
1900 | */ |
---|
1901 | rtems_status_code |
---|
1902 | rtems_bdbuf_syncdev (dev_t dev) |
---|
1903 | { |
---|
1904 | rtems_disk_device* dd; |
---|
1905 | rtems_bdbuf_pool* pool; |
---|
1906 | rtems_status_code sc; |
---|
1907 | rtems_event_set out; |
---|
1908 | |
---|
1909 | #if RTEMS_BDBUF_TRACE |
---|
1910 | rtems_bdbuf_printf ("syncdev: %08x\n", dev); |
---|
1911 | #endif |
---|
1912 | |
---|
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); |
---|
1931 | |
---|
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 | */ |
---|
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); |
---|
1949 | |
---|
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); |
---|
1956 | } |
---|
1957 | |
---|
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. |
---|
1961 | * |
---|
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 |
---|
1967 | */ |
---|
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 | /** |
---|
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. |
---|
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) |
---|
2001 | { |
---|
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 | /* |
---|
2014 | * Check if the buffer's hold timer has reached 0. If a sync is active |
---|
2015 | * force all the timers to 0. |
---|
2016 | * |
---|
2017 | * @note Lots of sync requests will skew this timer. It should be based |
---|
2018 | * on TOD to be accurate. Does it matter ? |
---|
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 |
---|
2042 | * assumption. Cannot use the transfer list being empty the sync dev |
---|
2043 | * calls sets the dev to use. |
---|
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 | } |
---|
2064 | |
---|
2065 | /** |
---|
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. |
---|
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; |
---|
2092 | boolean transfered_buffers = TRUE; |
---|
2093 | |
---|
2094 | rtems_chain_initialize_empty (&transfer); |
---|
2095 | |
---|
2096 | rtems_bdbuf_lock_pool (pool); |
---|
2097 | |
---|
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 | */ |
---|
2103 | if (pool->sync_active) |
---|
2104 | dev = pool->sync_device; |
---|
2105 | |
---|
2106 | /* |
---|
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. |
---|
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 | */ |
---|
2128 | |
---|
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)) |
---|
2135 | transfered_buffers = FALSE; |
---|
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); |
---|
2143 | if (dd == NULL) |
---|
2144 | transfered_buffers = FALSE; |
---|
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 | /* |
---|
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. |
---|
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 | /* |
---|
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. |
---|
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 | /* |
---|
2202 | * Perform the transfer if there are no more buffers, or the transfer |
---|
2203 | * size has reached the configured max. value. |
---|
2204 | */ |
---|
2205 | |
---|
2206 | if (rtems_chain_is_empty (&transfer) || |
---|
2207 | (write_req->count >= rtems_bdbuf_configuration.max_write_blocks)) |
---|
2208 | write = TRUE; |
---|
2209 | |
---|
2210 | if (write) |
---|
2211 | { |
---|
2212 | int result; |
---|
2213 | int b; |
---|
2214 | |
---|
2215 | /* |
---|
2216 | * Perform the transfer. No pool locks, no preemption, only the disk |
---|
2217 | * device is being held. |
---|
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 | * |
---|
2235 | * @warning Not sure this is the best option but I do not know |
---|
2236 | * what else can be done. |
---|
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; |
---|
2279 | } |
---|
2280 | } |
---|
2281 | |
---|
2282 | rtems_disk_release (dd); |
---|
2283 | } |
---|
2284 | } |
---|
2285 | |
---|
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 | } |
---|
2294 | |
---|
2295 | return transfered_buffers; |
---|
2296 | } |
---|
2297 | |
---|
2298 | /** |
---|
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. |
---|
2302 | */ |
---|
2303 | static rtems_task |
---|
2304 | rtems_bdbuf_swapout_task (rtems_task_argument arg) |
---|
2305 | { |
---|
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 | /* |
---|
2335 | * This is temporary. Needs to be changed to use the real time clock. |
---|
2336 | */ |
---|
2337 | timer_delta = period_in_msecs; |
---|
2338 | |
---|
2339 | while (context->swapout_enabled) |
---|
2340 | { |
---|
2341 | rtems_event_set out; |
---|
2342 | |
---|
2343 | /* |
---|
2344 | * Only update the timers once in the processing cycle. |
---|
2345 | */ |
---|
2346 | boolean update_timers = TRUE; |
---|
2347 | |
---|
2348 | /* |
---|
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. |
---|
2352 | */ |
---|
2353 | boolean transfered_buffers; |
---|
2354 | |
---|
2355 | do |
---|
2356 | { |
---|
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; |
---|
2374 | } |
---|
2375 | } |
---|
2376 | |
---|
2377 | /* |
---|
2378 | * Only update the timers once. |
---|
2379 | */ |
---|
2380 | update_timers = FALSE; |
---|
2381 | } |
---|
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); |
---|
2396 | } |
---|
2397 | |
---|
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. |
---|
2402 | * |
---|
2403 | * @param block_size Requested block size |
---|
2404 | * @param pool The pool to use for the requested pool size. |
---|
2405 | * |
---|
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. |
---|
2412 | */ |
---|
2413 | rtems_status_code |
---|
2414 | rtems_bdbuf_find_pool (int block_size, rtems_bdpool_id *pool) |
---|
2415 | { |
---|
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)) |
---|
2432 | { |
---|
2433 | curid = i; |
---|
2434 | cursize = p->blksize; |
---|
2435 | found = TRUE; |
---|
2436 | } |
---|
2437 | } |
---|
2438 | |
---|
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 | } |
---|
2449 | } |
---|
2450 | |
---|
2451 | /** |
---|
2452 | * Obtain characteristics of buffer pool with specified number. |
---|
2453 | * |
---|
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. |
---|
2458 | * |
---|
2459 | * RETURNS: |
---|
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. |
---|
2463 | * |
---|
2464 | * @note Buffer pools enumerated continuously starting from 0. |
---|
2465 | */ |
---|
2466 | rtems_status_code |
---|
2467 | rtems_bdbuf_get_pool_info (rtems_bdpool_id pool, int* block_size, int* blocks) |
---|
2468 | { |
---|
2469 | if (pool >= rtems_bdbuf_ctx.npools) |
---|
2470 | return RTEMS_INVALID_NUMBER; |
---|
2471 | |
---|
2472 | if (block_size != NULL) |
---|
2473 | { |
---|
2474 | *block_size = rtems_bdbuf_ctx.pool[pool].blksize; |
---|
2475 | } |
---|
2476 | |
---|
2477 | if (blocks != NULL) |
---|
2478 | { |
---|
2479 | *blocks = rtems_bdbuf_ctx.pool[pool].nblks; |
---|
2480 | } |
---|
2481 | |
---|
2482 | return RTEMS_SUCCESSFUL; |
---|
2483 | } |
---|