1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup rtems_bdbuf |
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5 | * |
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6 | * Block device buffer management. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Disk I/O buffering |
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11 | * Buffer managment |
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12 | * |
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13 | * Copyright (C) 2001 OKTET Ltd., St.-Peterburg, Russia |
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14 | * Author: Andrey G. Ivanov <Andrey.Ivanov@oktet.ru> |
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15 | * Victor V. Vengerov <vvv@oktet.ru> |
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16 | * Alexander Kukuta <kam@oktet.ru> |
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17 | * |
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18 | * Copyright (C) 2008,2009 Chris Johns <chrisj@rtems.org> |
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19 | * Rewritten to remove score mutex access. Fixes many performance |
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20 | * issues. |
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21 | * |
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22 | * @(#) bdbuf.c,v 1.14 2004/04/17 08:15:17 ralf Exp |
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23 | */ |
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24 | |
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25 | /** |
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26 | * Set to 1 to enable debug tracing. |
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27 | */ |
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28 | #define RTEMS_BDBUF_TRACE 0 |
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29 | |
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30 | #if HAVE_CONFIG_H |
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31 | #include "config.h" |
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32 | #endif |
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33 | |
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34 | #include <rtems.h> |
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35 | #include <rtems/error.h> |
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36 | #include <rtems/malloc.h> |
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37 | #include <limits.h> |
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38 | #include <errno.h> |
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39 | #include <assert.h> |
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40 | |
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41 | #if RTEMS_BDBUF_TRACE |
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42 | #include <stdio.h> |
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43 | #endif |
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44 | |
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45 | #include "rtems/bdbuf.h" |
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46 | |
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47 | /* |
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48 | * Simpler label for this file. |
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49 | */ |
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50 | #define bdbuf_config rtems_bdbuf_configuration |
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51 | |
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52 | /** |
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53 | * A swapout transfer transaction data. This data is passed to a worked thread |
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54 | * to handle the write phase of the transfer. |
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55 | */ |
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56 | typedef struct rtems_bdbuf_swapout_transfer |
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57 | { |
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58 | rtems_chain_control bds; /**< The transfer list of BDs. */ |
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59 | dev_t dev; /**< The device the transfer is for. */ |
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60 | rtems_blkdev_request* write_req; /**< The write request array. */ |
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61 | } rtems_bdbuf_swapout_transfer; |
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62 | |
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63 | /** |
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64 | * Swapout worker thread. These are available to take processing from the |
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65 | * main swapout thread and handle the I/O operation. |
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66 | */ |
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67 | typedef struct rtems_bdbuf_swapout_worker |
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68 | { |
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69 | rtems_chain_node link; /**< The threads sit on a chain when |
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70 | * idle. */ |
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71 | rtems_id id; /**< The id of the task so we can wake |
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72 | * it. */ |
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73 | volatile bool enabled; /**< The worked is enabled. */ |
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74 | rtems_bdbuf_swapout_transfer transfer; /**< The transfer data for this |
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75 | * thread. */ |
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76 | } rtems_bdbuf_swapout_worker; |
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77 | |
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78 | /** |
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79 | * The BD buffer cache. |
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80 | */ |
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81 | typedef struct rtems_bdbuf_cache |
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82 | { |
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83 | rtems_id swapout; /**< Swapout task ID */ |
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84 | volatile bool swapout_enabled; /**< Swapout is only running if |
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85 | * enabled. Set to false to kill the |
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86 | * swap out task. It deletes itself. */ |
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87 | rtems_chain_control swapout_workers; /**< The work threads for the swapout |
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88 | * task. */ |
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89 | |
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90 | rtems_bdbuf_buffer* bds; /**< Pointer to table of buffer |
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91 | * descriptors. */ |
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92 | void* buffers; /**< The buffer's memory. */ |
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93 | size_t buffer_min_count; /**< Number of minimum size buffers |
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94 | * that fit the buffer memory. */ |
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95 | size_t max_bds_per_group; /**< The number of BDs of minimum |
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96 | * buffer size that fit in a group. */ |
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97 | uint32_t flags; /**< Configuration flags. */ |
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98 | |
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99 | rtems_id lock; /**< The cache lock. It locks all |
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100 | * cache data, BD and lists. */ |
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101 | rtems_id sync_lock; /**< Sync calls block writes. */ |
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102 | volatile bool sync_active; /**< True if a sync is active. */ |
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103 | volatile rtems_id sync_requester; /**< The sync requester. */ |
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104 | volatile dev_t sync_device; /**< The device to sync and -1 not a |
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105 | * device sync. */ |
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106 | |
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107 | rtems_bdbuf_buffer* tree; /**< Buffer descriptor lookup AVL tree |
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108 | * root. There is only one. */ |
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109 | rtems_chain_control ready; /**< Free buffers list, read-ahead, or |
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110 | * resized group buffers. */ |
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111 | rtems_chain_control lru; /**< Least recently used list */ |
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112 | rtems_chain_control modified; /**< Modified buffers list */ |
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113 | rtems_chain_control sync; /**< Buffers to sync list */ |
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114 | |
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115 | rtems_id access; /**< Obtain if waiting for a buffer in |
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116 | * the ACCESS state. */ |
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117 | volatile uint32_t access_waiters; /**< Count of access blockers. */ |
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118 | rtems_id transfer; /**< Obtain if waiting for a buffer in |
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119 | * the TRANSFER state. */ |
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120 | volatile uint32_t transfer_waiters; /**< Count of transfer blockers. */ |
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121 | rtems_id waiting; /**< Obtain if waiting for a buffer |
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122 | * and the none are available. */ |
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123 | volatile uint32_t wait_waiters; /**< Count of waiting blockers. */ |
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124 | |
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125 | size_t group_count; /**< The number of groups. */ |
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126 | rtems_bdbuf_group* groups; /**< The groups. */ |
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127 | |
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128 | bool initialised; /**< Initialised state. */ |
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129 | } rtems_bdbuf_cache; |
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130 | |
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131 | /** |
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132 | * Fatal errors |
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133 | */ |
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134 | #define RTEMS_BLKDEV_FATAL_ERROR(n) \ |
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135 | (((uint32_t)'B' << 24) | ((uint32_t)(n) & (uint32_t)0x00FFFFFF)) |
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136 | |
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137 | #define RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY RTEMS_BLKDEV_FATAL_ERROR(1) |
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138 | #define RTEMS_BLKDEV_FATAL_BDBUF_SWAPOUT RTEMS_BLKDEV_FATAL_ERROR(2) |
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139 | #define RTEMS_BLKDEV_FATAL_BDBUF_SYNC_LOCK RTEMS_BLKDEV_FATAL_ERROR(3) |
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140 | #define RTEMS_BLKDEV_FATAL_BDBUF_SYNC_UNLOCK RTEMS_BLKDEV_FATAL_ERROR(4) |
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141 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_LOCK RTEMS_BLKDEV_FATAL_ERROR(5) |
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142 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_UNLOCK RTEMS_BLKDEV_FATAL_ERROR(6) |
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143 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_1 RTEMS_BLKDEV_FATAL_ERROR(7) |
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144 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_2 RTEMS_BLKDEV_FATAL_ERROR(8) |
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145 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_3 RTEMS_BLKDEV_FATAL_ERROR(9) |
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146 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAKE RTEMS_BLKDEV_FATAL_ERROR(10) |
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147 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE RTEMS_BLKDEV_FATAL_ERROR(11) |
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148 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM RTEMS_BLKDEV_FATAL_ERROR(12) |
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149 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_CREATE RTEMS_BLKDEV_FATAL_ERROR(13) |
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150 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_START RTEMS_BLKDEV_FATAL_ERROR(14) |
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151 | #define BLKDEV_FATAL_BDBUF_SWAPOUT_RE RTEMS_BLKDEV_FATAL_ERROR(15) |
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152 | #define BLKDEV_FATAL_BDBUF_SWAPOUT_TS RTEMS_BLKDEV_FATAL_ERROR(16) |
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153 | |
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154 | /** |
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155 | * The events used in this code. These should be system events rather than |
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156 | * application events. |
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157 | */ |
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158 | #define RTEMS_BDBUF_TRANSFER_SYNC RTEMS_EVENT_1 |
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159 | #define RTEMS_BDBUF_SWAPOUT_SYNC RTEMS_EVENT_2 |
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160 | |
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161 | /** |
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162 | * The swap out task size. Should be more than enough for most drivers with |
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163 | * tracing turned on. |
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164 | */ |
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165 | #define SWAPOUT_TASK_STACK_SIZE (8 * 1024) |
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166 | |
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167 | /** |
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168 | * Lock semaphore attributes. This is used for locking type mutexes. |
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169 | * |
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170 | * @warning Priority inheritance is on. |
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171 | */ |
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172 | #define RTEMS_BDBUF_CACHE_LOCK_ATTRIBS \ |
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173 | (RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | \ |
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174 | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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175 | |
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176 | /** |
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177 | * Waiter semaphore attributes. |
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178 | * |
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179 | * @warning Do not configure as inherit priority. If a driver is in the driver |
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180 | * initialisation table this locked semaphore will have the IDLE task |
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181 | * as the holder and a blocking task will raise the priority of the |
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182 | * IDLE task which can cause unsual side effects. |
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183 | */ |
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184 | #define RTEMS_BDBUF_CACHE_WAITER_ATTRIBS \ |
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185 | (RTEMS_PRIORITY | RTEMS_SIMPLE_BINARY_SEMAPHORE | \ |
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186 | RTEMS_NO_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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187 | |
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188 | /* |
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189 | * The swap out task. |
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190 | */ |
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191 | static rtems_task rtems_bdbuf_swapout_task(rtems_task_argument arg); |
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192 | |
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193 | /** |
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194 | * The Buffer Descriptor cache. |
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195 | */ |
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196 | static rtems_bdbuf_cache bdbuf_cache; |
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197 | |
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198 | /** |
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199 | * Print a message to the bdbuf trace output and flush it. |
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200 | * |
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201 | * @param format The format string. See printf for details. |
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202 | * @param ... The arguments for the format text. |
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203 | * @return int The number of bytes written to the output. |
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204 | */ |
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205 | #if RTEMS_BDBUF_TRACE |
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206 | bool rtems_bdbuf_tracer; |
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207 | static void |
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208 | rtems_bdbuf_printf (const char *format, ...) |
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209 | { |
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210 | va_list args; |
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211 | va_start (args, format); |
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212 | if (rtems_bdbuf_tracer) |
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213 | { |
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214 | fprintf (stdout, "bdbuf:"); |
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215 | vfprintf (stdout, format, args); |
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216 | fflush (stdout); |
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217 | } |
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218 | } |
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219 | #endif |
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220 | |
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221 | /** |
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222 | * The default maximum height of 32 allows for AVL trees having between |
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223 | * 5,704,880 and 4,294,967,295 nodes, depending on order of insertion. You may |
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224 | * change this compile-time constant as you wish. |
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225 | */ |
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226 | #ifndef RTEMS_BDBUF_AVL_MAX_HEIGHT |
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227 | #define RTEMS_BDBUF_AVL_MAX_HEIGHT (32) |
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228 | #endif |
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229 | |
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230 | /** |
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231 | * Searches for the node with specified dev/block. |
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232 | * |
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233 | * @param root pointer to the root node of the AVL-Tree |
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234 | * @param dev device search key |
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235 | * @param block block search key |
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236 | * @retval NULL node with the specified dev/block is not found |
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237 | * @return pointer to the node with specified dev/block |
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238 | */ |
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239 | static rtems_bdbuf_buffer * |
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240 | rtems_bdbuf_avl_search (rtems_bdbuf_buffer** root, |
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241 | dev_t dev, |
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242 | rtems_blkdev_bnum block) |
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243 | { |
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244 | rtems_bdbuf_buffer* p = *root; |
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245 | |
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246 | while ((p != NULL) && ((p->dev != dev) || (p->block != block))) |
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247 | { |
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248 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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249 | { |
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250 | p = p->avl.right; |
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251 | } |
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252 | else |
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253 | { |
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254 | p = p->avl.left; |
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255 | } |
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256 | } |
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257 | |
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258 | return p; |
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259 | } |
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260 | |
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261 | /** |
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262 | * Inserts the specified node to the AVl-Tree. |
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263 | * |
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264 | * @param root pointer to the root node of the AVL-Tree |
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265 | * @param node Pointer to the node to add. |
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266 | * @retval 0 The node added successfully |
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267 | * @retval -1 An error occured |
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268 | */ |
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269 | static int |
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270 | rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root, |
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271 | rtems_bdbuf_buffer* node) |
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272 | { |
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273 | dev_t dev = node->dev; |
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274 | rtems_blkdev_bnum block = node->block; |
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275 | |
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276 | rtems_bdbuf_buffer* p = *root; |
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277 | rtems_bdbuf_buffer* q; |
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278 | rtems_bdbuf_buffer* p1; |
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279 | rtems_bdbuf_buffer* p2; |
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280 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
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281 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
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282 | |
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283 | bool modified = false; |
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284 | |
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285 | if (p == NULL) |
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286 | { |
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287 | *root = node; |
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288 | node->avl.left = NULL; |
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289 | node->avl.right = NULL; |
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290 | node->avl.bal = 0; |
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291 | return 0; |
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292 | } |
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293 | |
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294 | while (p != NULL) |
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295 | { |
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296 | *buf_prev++ = p; |
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297 | |
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298 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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299 | { |
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300 | p->avl.cache = 1; |
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301 | q = p->avl.right; |
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302 | if (q == NULL) |
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303 | { |
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304 | q = node; |
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305 | p->avl.right = q = node; |
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306 | break; |
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307 | } |
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308 | } |
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309 | else if ((p->dev != dev) || (p->block != block)) |
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310 | { |
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311 | p->avl.cache = -1; |
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312 | q = p->avl.left; |
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313 | if (q == NULL) |
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314 | { |
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315 | q = node; |
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316 | p->avl.left = q; |
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317 | break; |
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318 | } |
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319 | } |
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320 | else |
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321 | { |
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322 | return -1; |
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323 | } |
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324 | |
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325 | p = q; |
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326 | } |
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327 | |
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328 | q->avl.left = q->avl.right = NULL; |
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329 | q->avl.bal = 0; |
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330 | modified = true; |
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331 | buf_prev--; |
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332 | |
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333 | while (modified) |
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334 | { |
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335 | if (p->avl.cache == -1) |
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336 | { |
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337 | switch (p->avl.bal) |
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338 | { |
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339 | case 1: |
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340 | p->avl.bal = 0; |
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341 | modified = false; |
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342 | break; |
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343 | |
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344 | case 0: |
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345 | p->avl.bal = -1; |
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346 | break; |
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347 | |
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348 | case -1: |
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349 | p1 = p->avl.left; |
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350 | if (p1->avl.bal == -1) /* simple LL-turn */ |
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351 | { |
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352 | p->avl.left = p1->avl.right; |
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353 | p1->avl.right = p; |
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354 | p->avl.bal = 0; |
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355 | p = p1; |
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356 | } |
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357 | else /* double LR-turn */ |
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358 | { |
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359 | p2 = p1->avl.right; |
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360 | p1->avl.right = p2->avl.left; |
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361 | p2->avl.left = p1; |
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362 | p->avl.left = p2->avl.right; |
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363 | p2->avl.right = p; |
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364 | if (p2->avl.bal == -1) p->avl.bal = +1; else p->avl.bal = 0; |
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365 | if (p2->avl.bal == +1) p1->avl.bal = -1; else p1->avl.bal = 0; |
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366 | p = p2; |
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367 | } |
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368 | p->avl.bal = 0; |
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369 | modified = false; |
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370 | break; |
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371 | |
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372 | default: |
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373 | break; |
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374 | } |
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375 | } |
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376 | else |
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377 | { |
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378 | switch (p->avl.bal) |
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379 | { |
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380 | case -1: |
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381 | p->avl.bal = 0; |
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382 | modified = false; |
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383 | break; |
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384 | |
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385 | case 0: |
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386 | p->avl.bal = 1; |
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387 | break; |
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388 | |
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389 | case 1: |
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390 | p1 = p->avl.right; |
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391 | if (p1->avl.bal == 1) /* simple RR-turn */ |
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392 | { |
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393 | p->avl.right = p1->avl.left; |
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394 | p1->avl.left = p; |
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395 | p->avl.bal = 0; |
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396 | p = p1; |
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397 | } |
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398 | else /* double RL-turn */ |
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399 | { |
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400 | p2 = p1->avl.left; |
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401 | p1->avl.left = p2->avl.right; |
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402 | p2->avl.right = p1; |
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403 | p->avl.right = p2->avl.left; |
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404 | p2->avl.left = p; |
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405 | if (p2->avl.bal == +1) p->avl.bal = -1; else p->avl.bal = 0; |
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406 | if (p2->avl.bal == -1) p1->avl.bal = +1; else p1->avl.bal = 0; |
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407 | p = p2; |
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408 | } |
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409 | p->avl.bal = 0; |
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410 | modified = false; |
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411 | break; |
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412 | |
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413 | default: |
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414 | break; |
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415 | } |
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416 | } |
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417 | q = p; |
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418 | if (buf_prev > buf_stack) |
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419 | { |
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420 | p = *--buf_prev; |
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421 | |
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422 | if (p->avl.cache == -1) |
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423 | { |
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424 | p->avl.left = q; |
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425 | } |
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426 | else |
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427 | { |
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428 | p->avl.right = q; |
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429 | } |
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430 | } |
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431 | else |
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432 | { |
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433 | *root = p; |
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434 | break; |
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435 | } |
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436 | }; |
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437 | |
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438 | return 0; |
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439 | } |
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440 | |
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441 | |
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442 | /** |
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443 | * Removes the node from the tree. |
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444 | * |
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445 | * @param root Pointer to pointer to the root node |
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446 | * @param node Pointer to the node to remove |
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447 | * @retval 0 Item removed |
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448 | * @retval -1 No such item found |
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449 | */ |
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450 | static int |
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451 | rtems_bdbuf_avl_remove(rtems_bdbuf_buffer** root, |
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452 | const rtems_bdbuf_buffer* node) |
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453 | { |
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454 | dev_t dev = node->dev; |
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455 | rtems_blkdev_bnum block = node->block; |
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456 | |
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457 | rtems_bdbuf_buffer* p = *root; |
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458 | rtems_bdbuf_buffer* q; |
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459 | rtems_bdbuf_buffer* r; |
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460 | rtems_bdbuf_buffer* s; |
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461 | rtems_bdbuf_buffer* p1; |
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462 | rtems_bdbuf_buffer* p2; |
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463 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
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464 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
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465 | |
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466 | bool modified = false; |
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467 | |
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468 | memset (buf_stack, 0, sizeof(buf_stack)); |
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469 | |
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470 | while (p != NULL) |
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471 | { |
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472 | *buf_prev++ = p; |
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473 | |
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474 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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475 | { |
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476 | p->avl.cache = 1; |
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477 | p = p->avl.right; |
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478 | } |
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479 | else if ((p->dev != dev) || (p->block != block)) |
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480 | { |
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481 | p->avl.cache = -1; |
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482 | p = p->avl.left; |
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483 | } |
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484 | else |
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485 | { |
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486 | /* node found */ |
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487 | break; |
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488 | } |
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489 | } |
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490 | |
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491 | if (p == NULL) |
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492 | { |
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493 | /* there is no such node */ |
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494 | return -1; |
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495 | } |
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496 | |
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497 | q = p; |
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498 | |
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499 | buf_prev--; |
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500 | if (buf_prev > buf_stack) |
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501 | { |
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502 | p = *(buf_prev - 1); |
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503 | } |
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504 | else |
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505 | { |
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506 | p = NULL; |
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507 | } |
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508 | |
---|
509 | /* at this moment q - is a node to delete, p is q's parent */ |
---|
510 | if (q->avl.right == NULL) |
---|
511 | { |
---|
512 | r = q->avl.left; |
---|
513 | if (r != NULL) |
---|
514 | { |
---|
515 | r->avl.bal = 0; |
---|
516 | } |
---|
517 | q = r; |
---|
518 | } |
---|
519 | else |
---|
520 | { |
---|
521 | rtems_bdbuf_buffer **t; |
---|
522 | |
---|
523 | r = q->avl.right; |
---|
524 | |
---|
525 | if (r->avl.left == NULL) |
---|
526 | { |
---|
527 | r->avl.left = q->avl.left; |
---|
528 | r->avl.bal = q->avl.bal; |
---|
529 | r->avl.cache = 1; |
---|
530 | *buf_prev++ = q = r; |
---|
531 | } |
---|
532 | else |
---|
533 | { |
---|
534 | t = buf_prev++; |
---|
535 | s = r; |
---|
536 | |
---|
537 | while (s->avl.left != NULL) |
---|
538 | { |
---|
539 | *buf_prev++ = r = s; |
---|
540 | s = r->avl.left; |
---|
541 | r->avl.cache = -1; |
---|
542 | } |
---|
543 | |
---|
544 | s->avl.left = q->avl.left; |
---|
545 | r->avl.left = s->avl.right; |
---|
546 | s->avl.right = q->avl.right; |
---|
547 | s->avl.bal = q->avl.bal; |
---|
548 | s->avl.cache = 1; |
---|
549 | |
---|
550 | *t = q = s; |
---|
551 | } |
---|
552 | } |
---|
553 | |
---|
554 | if (p != NULL) |
---|
555 | { |
---|
556 | if (p->avl.cache == -1) |
---|
557 | { |
---|
558 | p->avl.left = q; |
---|
559 | } |
---|
560 | else |
---|
561 | { |
---|
562 | p->avl.right = q; |
---|
563 | } |
---|
564 | } |
---|
565 | else |
---|
566 | { |
---|
567 | *root = q; |
---|
568 | } |
---|
569 | |
---|
570 | modified = true; |
---|
571 | |
---|
572 | while (modified) |
---|
573 | { |
---|
574 | if (buf_prev > buf_stack) |
---|
575 | { |
---|
576 | p = *--buf_prev; |
---|
577 | } |
---|
578 | else |
---|
579 | { |
---|
580 | break; |
---|
581 | } |
---|
582 | |
---|
583 | if (p->avl.cache == -1) |
---|
584 | { |
---|
585 | /* rebalance left branch */ |
---|
586 | switch (p->avl.bal) |
---|
587 | { |
---|
588 | case -1: |
---|
589 | p->avl.bal = 0; |
---|
590 | break; |
---|
591 | case 0: |
---|
592 | p->avl.bal = 1; |
---|
593 | modified = false; |
---|
594 | break; |
---|
595 | |
---|
596 | case +1: |
---|
597 | p1 = p->avl.right; |
---|
598 | |
---|
599 | if (p1->avl.bal >= 0) /* simple RR-turn */ |
---|
600 | { |
---|
601 | p->avl.right = p1->avl.left; |
---|
602 | p1->avl.left = p; |
---|
603 | |
---|
604 | if (p1->avl.bal == 0) |
---|
605 | { |
---|
606 | p1->avl.bal = -1; |
---|
607 | modified = false; |
---|
608 | } |
---|
609 | else |
---|
610 | { |
---|
611 | p->avl.bal = 0; |
---|
612 | p1->avl.bal = 0; |
---|
613 | } |
---|
614 | p = p1; |
---|
615 | } |
---|
616 | else /* double RL-turn */ |
---|
617 | { |
---|
618 | p2 = p1->avl.left; |
---|
619 | |
---|
620 | p1->avl.left = p2->avl.right; |
---|
621 | p2->avl.right = p1; |
---|
622 | p->avl.right = p2->avl.left; |
---|
623 | p2->avl.left = p; |
---|
624 | |
---|
625 | if (p2->avl.bal == +1) p->avl.bal = -1; else p->avl.bal = 0; |
---|
626 | if (p2->avl.bal == -1) p1->avl.bal = 1; else p1->avl.bal = 0; |
---|
627 | |
---|
628 | p = p2; |
---|
629 | p2->avl.bal = 0; |
---|
630 | } |
---|
631 | break; |
---|
632 | |
---|
633 | default: |
---|
634 | break; |
---|
635 | } |
---|
636 | } |
---|
637 | else |
---|
638 | { |
---|
639 | /* rebalance right branch */ |
---|
640 | switch (p->avl.bal) |
---|
641 | { |
---|
642 | case +1: |
---|
643 | p->avl.bal = 0; |
---|
644 | break; |
---|
645 | |
---|
646 | case 0: |
---|
647 | p->avl.bal = -1; |
---|
648 | modified = false; |
---|
649 | break; |
---|
650 | |
---|
651 | case -1: |
---|
652 | p1 = p->avl.left; |
---|
653 | |
---|
654 | if (p1->avl.bal <= 0) /* simple LL-turn */ |
---|
655 | { |
---|
656 | p->avl.left = p1->avl.right; |
---|
657 | p1->avl.right = p; |
---|
658 | if (p1->avl.bal == 0) |
---|
659 | { |
---|
660 | p1->avl.bal = 1; |
---|
661 | modified = false; |
---|
662 | } |
---|
663 | else |
---|
664 | { |
---|
665 | p->avl.bal = 0; |
---|
666 | p1->avl.bal = 0; |
---|
667 | } |
---|
668 | p = p1; |
---|
669 | } |
---|
670 | else /* double LR-turn */ |
---|
671 | { |
---|
672 | p2 = p1->avl.right; |
---|
673 | |
---|
674 | p1->avl.right = p2->avl.left; |
---|
675 | p2->avl.left = p1; |
---|
676 | p->avl.left = p2->avl.right; |
---|
677 | p2->avl.right = p; |
---|
678 | |
---|
679 | if (p2->avl.bal == -1) p->avl.bal = 1; else p->avl.bal = 0; |
---|
680 | if (p2->avl.bal == +1) p1->avl.bal = -1; else p1->avl.bal = 0; |
---|
681 | |
---|
682 | p = p2; |
---|
683 | p2->avl.bal = 0; |
---|
684 | } |
---|
685 | break; |
---|
686 | |
---|
687 | default: |
---|
688 | break; |
---|
689 | } |
---|
690 | } |
---|
691 | |
---|
692 | if (buf_prev > buf_stack) |
---|
693 | { |
---|
694 | q = *(buf_prev - 1); |
---|
695 | |
---|
696 | if (q->avl.cache == -1) |
---|
697 | { |
---|
698 | q->avl.left = p; |
---|
699 | } |
---|
700 | else |
---|
701 | { |
---|
702 | q->avl.right = p; |
---|
703 | } |
---|
704 | } |
---|
705 | else |
---|
706 | { |
---|
707 | *root = p; |
---|
708 | break; |
---|
709 | } |
---|
710 | |
---|
711 | } |
---|
712 | |
---|
713 | return 0; |
---|
714 | } |
---|
715 | |
---|
716 | /** |
---|
717 | * Lock the mutex. A single task can nest calls. |
---|
718 | * |
---|
719 | * @param lock The mutex to lock. |
---|
720 | * @param fatal_error_code The error code if the call fails. |
---|
721 | */ |
---|
722 | static void |
---|
723 | rtems_bdbuf_lock (rtems_id lock, uint32_t fatal_error_code) |
---|
724 | { |
---|
725 | rtems_status_code sc = rtems_semaphore_obtain (lock, |
---|
726 | RTEMS_WAIT, |
---|
727 | RTEMS_NO_TIMEOUT); |
---|
728 | if (sc != RTEMS_SUCCESSFUL) |
---|
729 | rtems_fatal_error_occurred (fatal_error_code); |
---|
730 | } |
---|
731 | |
---|
732 | /** |
---|
733 | * Unlock the mutex. |
---|
734 | * |
---|
735 | * @param lock The mutex to unlock. |
---|
736 | * @param fatal_error_code The error code if the call fails. |
---|
737 | */ |
---|
738 | static void |
---|
739 | rtems_bdbuf_unlock (rtems_id lock, uint32_t fatal_error_code) |
---|
740 | { |
---|
741 | rtems_status_code sc = rtems_semaphore_release (lock); |
---|
742 | if (sc != RTEMS_SUCCESSFUL) |
---|
743 | rtems_fatal_error_occurred (fatal_error_code); |
---|
744 | } |
---|
745 | |
---|
746 | /** |
---|
747 | * Lock the cache. A single task can nest calls. |
---|
748 | */ |
---|
749 | static void |
---|
750 | rtems_bdbuf_lock_cache (void) |
---|
751 | { |
---|
752 | rtems_bdbuf_lock (bdbuf_cache.lock, RTEMS_BLKDEV_FATAL_BDBUF_CACHE_LOCK); |
---|
753 | } |
---|
754 | |
---|
755 | /** |
---|
756 | * Unlock the cache. |
---|
757 | */ |
---|
758 | static void |
---|
759 | rtems_bdbuf_unlock_cache (void) |
---|
760 | { |
---|
761 | rtems_bdbuf_unlock (bdbuf_cache.lock, RTEMS_BLKDEV_FATAL_BDBUF_CACHE_UNLOCK); |
---|
762 | } |
---|
763 | |
---|
764 | /** |
---|
765 | * Lock the cache's sync. A single task can nest calls. |
---|
766 | */ |
---|
767 | static void |
---|
768 | rtems_bdbuf_lock_sync (void) |
---|
769 | { |
---|
770 | rtems_bdbuf_lock (bdbuf_cache.sync_lock, RTEMS_BLKDEV_FATAL_BDBUF_SYNC_LOCK); |
---|
771 | } |
---|
772 | |
---|
773 | /** |
---|
774 | * Unlock the cache's sync lock. Any blocked writers are woken. |
---|
775 | */ |
---|
776 | static void |
---|
777 | rtems_bdbuf_unlock_sync (void) |
---|
778 | { |
---|
779 | rtems_bdbuf_unlock (bdbuf_cache.sync_lock, |
---|
780 | RTEMS_BLKDEV_FATAL_BDBUF_SYNC_UNLOCK); |
---|
781 | } |
---|
782 | |
---|
783 | /** |
---|
784 | * Wait until woken. Semaphores are used so a number of tasks can wait and can |
---|
785 | * be woken at once. Task events would require we maintain a list of tasks to |
---|
786 | * be woken and this would require storgage and we do not know the number of |
---|
787 | * tasks that could be waiting. |
---|
788 | * |
---|
789 | * While we have the cache locked we can try and claim the semaphore and |
---|
790 | * therefore know when we release the lock to the cache we will block until the |
---|
791 | * semaphore is released. This may even happen before we get to block. |
---|
792 | * |
---|
793 | * A counter is used to save the release call when no one is waiting. |
---|
794 | * |
---|
795 | * The function assumes the cache is locked on entry and it will be locked on |
---|
796 | * exit. |
---|
797 | * |
---|
798 | * @param sema The semaphore to block on and wait. |
---|
799 | * @param waiters The wait counter for this semaphore. |
---|
800 | */ |
---|
801 | static void |
---|
802 | rtems_bdbuf_wait (rtems_id* sema, volatile uint32_t* waiters) |
---|
803 | { |
---|
804 | rtems_status_code sc; |
---|
805 | rtems_mode prev_mode; |
---|
806 | |
---|
807 | /* |
---|
808 | * Indicate we are waiting. |
---|
809 | */ |
---|
810 | *waiters += 1; |
---|
811 | |
---|
812 | /* |
---|
813 | * Disable preemption then unlock the cache and block. There is no POSIX |
---|
814 | * condition variable in the core API so this is a work around. |
---|
815 | * |
---|
816 | * The issue is a task could preempt after the cache is unlocked because it is |
---|
817 | * blocking or just hits that window, and before this task has blocked on the |
---|
818 | * semaphore. If the preempting task flushes the queue this task will not see |
---|
819 | * the flush and may block for ever or until another transaction flushes this |
---|
820 | * semaphore. |
---|
821 | */ |
---|
822 | sc = rtems_task_mode (RTEMS_NO_PREEMPT, RTEMS_PREEMPT_MASK, &prev_mode); |
---|
823 | |
---|
824 | if (sc != RTEMS_SUCCESSFUL) |
---|
825 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_1); |
---|
826 | |
---|
827 | /* |
---|
828 | * Unlock the cache, wait, and lock the cache when we return. |
---|
829 | */ |
---|
830 | rtems_bdbuf_unlock_cache (); |
---|
831 | |
---|
832 | sc = rtems_semaphore_obtain (*sema, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
---|
833 | |
---|
834 | if (sc != RTEMS_UNSATISFIED) |
---|
835 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_2); |
---|
836 | |
---|
837 | rtems_bdbuf_lock_cache (); |
---|
838 | |
---|
839 | sc = rtems_task_mode (prev_mode, RTEMS_ALL_MODE_MASKS, &prev_mode); |
---|
840 | |
---|
841 | if (sc != RTEMS_SUCCESSFUL) |
---|
842 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_3); |
---|
843 | |
---|
844 | *waiters -= 1; |
---|
845 | } |
---|
846 | |
---|
847 | /** |
---|
848 | * Wake a blocked resource. The resource has a counter that lets us know if |
---|
849 | * there are any waiters. |
---|
850 | * |
---|
851 | * @param sema The semaphore to release. |
---|
852 | * @param waiters The wait counter for this semaphore. |
---|
853 | */ |
---|
854 | static void |
---|
855 | rtems_bdbuf_wake (rtems_id sema, volatile uint32_t* waiters) |
---|
856 | { |
---|
857 | if (*waiters) |
---|
858 | { |
---|
859 | rtems_status_code sc; |
---|
860 | |
---|
861 | sc = rtems_semaphore_flush (sema); |
---|
862 | |
---|
863 | if (sc != RTEMS_SUCCESSFUL) |
---|
864 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAKE); |
---|
865 | } |
---|
866 | } |
---|
867 | |
---|
868 | /** |
---|
869 | * Add a buffer descriptor to the modified list. This modified list is treated |
---|
870 | * a litte differently to the other lists. To access it you must have the cache |
---|
871 | * locked and this is assumed to be the case on entry to this call. |
---|
872 | * |
---|
873 | * If the cache has a device being sync'ed and the bd is for that device the |
---|
874 | * call must block and wait until the sync is over before adding the bd to the |
---|
875 | * modified list. Once a sync happens for a device no bd's can be added the |
---|
876 | * modified list. The disk image is forced to be snapshot at that moment in |
---|
877 | * time. |
---|
878 | * |
---|
879 | * and you must |
---|
880 | * hold the sync lock. The sync lock is used to block writes while a sync is |
---|
881 | * active. |
---|
882 | * |
---|
883 | * @param bd The bd to queue to the cache's modified list. |
---|
884 | */ |
---|
885 | static void |
---|
886 | rtems_bdbuf_append_modified (rtems_bdbuf_buffer* bd) |
---|
887 | { |
---|
888 | /* |
---|
889 | * If the cache has a device being sync'ed check if this bd is for that |
---|
890 | * device. If it is unlock the cache and block on the sync lock. Once we have |
---|
891 | * the sync lock release it. |
---|
892 | */ |
---|
893 | if (bdbuf_cache.sync_active && (bdbuf_cache.sync_device == bd->dev)) |
---|
894 | { |
---|
895 | rtems_bdbuf_unlock_cache (); |
---|
896 | /* Wait for the sync lock */ |
---|
897 | rtems_bdbuf_lock_sync (); |
---|
898 | rtems_bdbuf_unlock_sync (); |
---|
899 | rtems_bdbuf_lock_cache (); |
---|
900 | } |
---|
901 | |
---|
902 | bd->state = RTEMS_BDBUF_STATE_MODIFIED; |
---|
903 | |
---|
904 | rtems_chain_append (&bdbuf_cache.modified, &bd->link); |
---|
905 | } |
---|
906 | |
---|
907 | /** |
---|
908 | * Wait the swapper task. |
---|
909 | */ |
---|
910 | static void |
---|
911 | rtems_bdbuf_wake_swapper (void) |
---|
912 | { |
---|
913 | rtems_status_code sc = rtems_event_send (bdbuf_cache.swapout, |
---|
914 | RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
915 | if (sc != RTEMS_SUCCESSFUL) |
---|
916 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE); |
---|
917 | } |
---|
918 | |
---|
919 | /** |
---|
920 | * Compute the number of BDs per group for a given buffer size. |
---|
921 | * |
---|
922 | * @param size The buffer size. It can be any size and we scale up. |
---|
923 | */ |
---|
924 | static size_t |
---|
925 | rtems_bdbuf_bds_per_group (size_t size) |
---|
926 | { |
---|
927 | size_t bufs_per_size; |
---|
928 | size_t bds_per_size; |
---|
929 | |
---|
930 | if (size > rtems_bdbuf_configuration.buffer_max) |
---|
931 | return 0; |
---|
932 | |
---|
933 | bufs_per_size = ((size - 1) / bdbuf_config.buffer_min) + 1; |
---|
934 | |
---|
935 | for (bds_per_size = 1; |
---|
936 | bds_per_size < bufs_per_size; |
---|
937 | bds_per_size <<= 1) |
---|
938 | ; |
---|
939 | |
---|
940 | return bdbuf_cache.max_bds_per_group / bds_per_size; |
---|
941 | } |
---|
942 | |
---|
943 | /** |
---|
944 | * Reallocate a group. The BDs currently allocated in the group are removed |
---|
945 | * from the ALV tree and any lists then the new BD's are prepended to the ready |
---|
946 | * list of the cache. |
---|
947 | * |
---|
948 | * @param group The group to reallocate. |
---|
949 | * @param new_bds_per_group The new count of BDs per group. |
---|
950 | */ |
---|
951 | static void |
---|
952 | rtems_bdbuf_group_realloc (rtems_bdbuf_group* group, size_t new_bds_per_group) |
---|
953 | { |
---|
954 | rtems_bdbuf_buffer* bd; |
---|
955 | int b; |
---|
956 | size_t bufs_per_bd; |
---|
957 | |
---|
958 | bufs_per_bd = bdbuf_cache.max_bds_per_group / group->bds_per_group; |
---|
959 | |
---|
960 | for (b = 0, bd = group->bdbuf; |
---|
961 | b < group->bds_per_group; |
---|
962 | b++, bd += bufs_per_bd) |
---|
963 | { |
---|
964 | if ((bd->state == RTEMS_BDBUF_STATE_CACHED) || |
---|
965 | (bd->state == RTEMS_BDBUF_STATE_MODIFIED) || |
---|
966 | (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD)) |
---|
967 | { |
---|
968 | if (rtems_bdbuf_avl_remove (&bdbuf_cache.tree, bd) != 0) |
---|
969 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
970 | rtems_chain_extract (&bd->link); |
---|
971 | } |
---|
972 | } |
---|
973 | |
---|
974 | group->bds_per_group = new_bds_per_group; |
---|
975 | bufs_per_bd = bdbuf_cache.max_bds_per_group / new_bds_per_group; |
---|
976 | |
---|
977 | for (b = 0, bd = group->bdbuf; |
---|
978 | b < group->bds_per_group; |
---|
979 | b++, bd += bufs_per_bd) |
---|
980 | rtems_chain_prepend (&bdbuf_cache.ready, &bd->link); |
---|
981 | } |
---|
982 | |
---|
983 | /** |
---|
984 | * Get the next BD from the list. This call assumes the cache is locked. |
---|
985 | * |
---|
986 | * @param bds_per_group The number of BDs per block we are need. |
---|
987 | * @param list The list to find the BD on. |
---|
988 | * @return The next BD if found or NULL is none are available. |
---|
989 | */ |
---|
990 | static rtems_bdbuf_buffer* |
---|
991 | rtems_bdbuf_get_next_bd (size_t bds_per_group, |
---|
992 | rtems_chain_control* list) |
---|
993 | { |
---|
994 | rtems_chain_node* node = rtems_chain_first (list); |
---|
995 | while (!rtems_chain_is_tail (list, node)) |
---|
996 | { |
---|
997 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
998 | |
---|
999 | /* |
---|
1000 | * If this bd is already part of a group that supports the same number of |
---|
1001 | * BDs per group return it. If the bd is part of another group check the |
---|
1002 | * number of users and if 0 we can take this group and resize it. |
---|
1003 | */ |
---|
1004 | if (bd->group->bds_per_group == bds_per_group) |
---|
1005 | { |
---|
1006 | rtems_chain_extract (node); |
---|
1007 | bd->group->users++; |
---|
1008 | return bd; |
---|
1009 | } |
---|
1010 | |
---|
1011 | if (bd->group->users == 0) |
---|
1012 | { |
---|
1013 | /* |
---|
1014 | * We use the group to locate the start of the BDs for this group. |
---|
1015 | */ |
---|
1016 | rtems_bdbuf_group_realloc (bd->group, bds_per_group); |
---|
1017 | bd = (rtems_bdbuf_buffer*) rtems_chain_get (&bdbuf_cache.ready); |
---|
1018 | return bd; |
---|
1019 | } |
---|
1020 | |
---|
1021 | node = rtems_chain_next (node); |
---|
1022 | } |
---|
1023 | |
---|
1024 | return NULL; |
---|
1025 | } |
---|
1026 | |
---|
1027 | /** |
---|
1028 | * Initialise the cache. |
---|
1029 | * |
---|
1030 | * @return rtems_status_code The initialisation status. |
---|
1031 | */ |
---|
1032 | rtems_status_code |
---|
1033 | rtems_bdbuf_init (void) |
---|
1034 | { |
---|
1035 | rtems_bdbuf_group* group; |
---|
1036 | rtems_bdbuf_buffer* bd; |
---|
1037 | uint8_t* buffer; |
---|
1038 | int b; |
---|
1039 | int cache_aligment; |
---|
1040 | rtems_status_code sc; |
---|
1041 | |
---|
1042 | #if RTEMS_BDBUF_TRACE |
---|
1043 | rtems_bdbuf_printf ("init\n"); |
---|
1044 | #endif |
---|
1045 | |
---|
1046 | /* |
---|
1047 | * Check the configuration table values. |
---|
1048 | */ |
---|
1049 | if ((bdbuf_config.buffer_max % bdbuf_config.buffer_min) != 0) |
---|
1050 | return RTEMS_INVALID_NUMBER; |
---|
1051 | |
---|
1052 | /* |
---|
1053 | * We use a special variable to manage the initialisation incase we have |
---|
1054 | * completing threads doing this. You may get errors if the another thread |
---|
1055 | * makes a call and we have not finished initialisation. |
---|
1056 | */ |
---|
1057 | if (bdbuf_cache.initialised) |
---|
1058 | return RTEMS_RESOURCE_IN_USE; |
---|
1059 | |
---|
1060 | bdbuf_cache.initialised = true; |
---|
1061 | |
---|
1062 | /* |
---|
1063 | * For unspecified cache alignments we use the CPU alignment. |
---|
1064 | */ |
---|
1065 | cache_aligment = 32; /* FIXME rtems_cache_get_data_line_size() */ |
---|
1066 | if (cache_aligment <= 0) |
---|
1067 | cache_aligment = CPU_ALIGNMENT; |
---|
1068 | |
---|
1069 | bdbuf_cache.sync_active = false; |
---|
1070 | bdbuf_cache.sync_device = -1; |
---|
1071 | bdbuf_cache.sync_requester = 0; |
---|
1072 | bdbuf_cache.tree = NULL; |
---|
1073 | |
---|
1074 | rtems_chain_initialize_empty (&bdbuf_cache.swapout_workers); |
---|
1075 | rtems_chain_initialize_empty (&bdbuf_cache.ready); |
---|
1076 | rtems_chain_initialize_empty (&bdbuf_cache.lru); |
---|
1077 | rtems_chain_initialize_empty (&bdbuf_cache.modified); |
---|
1078 | rtems_chain_initialize_empty (&bdbuf_cache.sync); |
---|
1079 | |
---|
1080 | bdbuf_cache.access = 0; |
---|
1081 | bdbuf_cache.access_waiters = 0; |
---|
1082 | bdbuf_cache.transfer = 0; |
---|
1083 | bdbuf_cache.transfer_waiters = 0; |
---|
1084 | bdbuf_cache.waiting = 0; |
---|
1085 | bdbuf_cache.wait_waiters = 0; |
---|
1086 | |
---|
1087 | /* |
---|
1088 | * Create the locks for the cache. |
---|
1089 | */ |
---|
1090 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'l'), |
---|
1091 | 1, RTEMS_BDBUF_CACHE_LOCK_ATTRIBS, 0, |
---|
1092 | &bdbuf_cache.lock); |
---|
1093 | if (sc != RTEMS_SUCCESSFUL) |
---|
1094 | { |
---|
1095 | bdbuf_cache.initialised = false; |
---|
1096 | return sc; |
---|
1097 | } |
---|
1098 | |
---|
1099 | rtems_bdbuf_lock_cache (); |
---|
1100 | |
---|
1101 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 's'), |
---|
1102 | 1, RTEMS_BDBUF_CACHE_LOCK_ATTRIBS, 0, |
---|
1103 | &bdbuf_cache.sync_lock); |
---|
1104 | if (sc != RTEMS_SUCCESSFUL) |
---|
1105 | { |
---|
1106 | rtems_bdbuf_unlock_cache (); |
---|
1107 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1108 | bdbuf_cache.initialised = false; |
---|
1109 | return sc; |
---|
1110 | } |
---|
1111 | |
---|
1112 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'a'), |
---|
1113 | 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0, |
---|
1114 | &bdbuf_cache.access); |
---|
1115 | if (sc != RTEMS_SUCCESSFUL) |
---|
1116 | { |
---|
1117 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1118 | rtems_bdbuf_unlock_cache (); |
---|
1119 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1120 | bdbuf_cache.initialised = false; |
---|
1121 | return sc; |
---|
1122 | } |
---|
1123 | |
---|
1124 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 't'), |
---|
1125 | 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0, |
---|
1126 | &bdbuf_cache.transfer); |
---|
1127 | if (sc != RTEMS_SUCCESSFUL) |
---|
1128 | { |
---|
1129 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1130 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1131 | rtems_bdbuf_unlock_cache (); |
---|
1132 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1133 | bdbuf_cache.initialised = false; |
---|
1134 | return sc; |
---|
1135 | } |
---|
1136 | |
---|
1137 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'w'), |
---|
1138 | 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0, |
---|
1139 | &bdbuf_cache.waiting); |
---|
1140 | if (sc != RTEMS_SUCCESSFUL) |
---|
1141 | { |
---|
1142 | rtems_semaphore_delete (bdbuf_cache.transfer); |
---|
1143 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1144 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1145 | rtems_bdbuf_unlock_cache (); |
---|
1146 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1147 | bdbuf_cache.initialised = false; |
---|
1148 | return sc; |
---|
1149 | } |
---|
1150 | |
---|
1151 | /* |
---|
1152 | * Allocate the memory for the buffer descriptors. |
---|
1153 | */ |
---|
1154 | bdbuf_cache.bds = calloc (sizeof (rtems_bdbuf_buffer), |
---|
1155 | bdbuf_config.size / bdbuf_config.buffer_min); |
---|
1156 | if (!bdbuf_cache.bds) |
---|
1157 | { |
---|
1158 | rtems_semaphore_delete (bdbuf_cache.transfer); |
---|
1159 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1160 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1161 | rtems_bdbuf_unlock_cache (); |
---|
1162 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1163 | bdbuf_cache.initialised = false; |
---|
1164 | return RTEMS_NO_MEMORY; |
---|
1165 | } |
---|
1166 | |
---|
1167 | /* |
---|
1168 | * Compute the various number of elements in the cache. |
---|
1169 | */ |
---|
1170 | bdbuf_cache.buffer_min_count = |
---|
1171 | bdbuf_config.size / bdbuf_config.buffer_min; |
---|
1172 | bdbuf_cache.max_bds_per_group = |
---|
1173 | bdbuf_config.buffer_max / bdbuf_config.buffer_min; |
---|
1174 | bdbuf_cache.group_count = |
---|
1175 | bdbuf_cache.buffer_min_count / bdbuf_cache.max_bds_per_group; |
---|
1176 | |
---|
1177 | /* |
---|
1178 | * Allocate the memory for the buffer descriptors. |
---|
1179 | */ |
---|
1180 | bdbuf_cache.groups = calloc (sizeof (rtems_bdbuf_group), |
---|
1181 | bdbuf_cache.group_count); |
---|
1182 | if (!bdbuf_cache.groups) |
---|
1183 | { |
---|
1184 | free (bdbuf_cache.bds); |
---|
1185 | rtems_semaphore_delete (bdbuf_cache.transfer); |
---|
1186 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1187 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1188 | rtems_bdbuf_unlock_cache (); |
---|
1189 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1190 | bdbuf_cache.initialised = false; |
---|
1191 | return RTEMS_NO_MEMORY; |
---|
1192 | } |
---|
1193 | |
---|
1194 | /* |
---|
1195 | * Allocate memory for buffer memory. The buffer memory will be cache |
---|
1196 | * aligned. It is possible to free the memory allocated by rtems_memalign() |
---|
1197 | * with free(). Return 0 if allocated. |
---|
1198 | */ |
---|
1199 | if (rtems_memalign ((void **) &bdbuf_cache.buffers, |
---|
1200 | cache_aligment, |
---|
1201 | bdbuf_cache.buffer_min_count * bdbuf_config.buffer_min) != 0) |
---|
1202 | { |
---|
1203 | free (bdbuf_cache.groups); |
---|
1204 | free (bdbuf_cache.bds); |
---|
1205 | rtems_semaphore_delete (bdbuf_cache.transfer); |
---|
1206 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1207 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1208 | rtems_bdbuf_unlock_cache (); |
---|
1209 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1210 | bdbuf_cache.initialised = false; |
---|
1211 | return RTEMS_NO_MEMORY; |
---|
1212 | } |
---|
1213 | |
---|
1214 | /* |
---|
1215 | * The cache is empty after opening so we need to add all the buffers to it |
---|
1216 | * and initialise the groups. |
---|
1217 | */ |
---|
1218 | for (b = 0, group = bdbuf_cache.groups, |
---|
1219 | bd = bdbuf_cache.bds, buffer = bdbuf_cache.buffers; |
---|
1220 | b < bdbuf_cache.buffer_min_count; |
---|
1221 | b++, bd++, buffer += bdbuf_config.buffer_min) |
---|
1222 | { |
---|
1223 | bd->dev = -1; |
---|
1224 | bd->group = group; |
---|
1225 | bd->buffer = buffer; |
---|
1226 | bd->avl.left = NULL; |
---|
1227 | bd->avl.right = NULL; |
---|
1228 | bd->state = RTEMS_BDBUF_STATE_EMPTY; |
---|
1229 | bd->error = 0; |
---|
1230 | bd->waiters = 0; |
---|
1231 | bd->hold_timer = 0; |
---|
1232 | |
---|
1233 | rtems_chain_append (&bdbuf_cache.ready, &bd->link); |
---|
1234 | |
---|
1235 | if ((b % bdbuf_cache.max_bds_per_group) == |
---|
1236 | (bdbuf_cache.max_bds_per_group - 1)) |
---|
1237 | group++; |
---|
1238 | } |
---|
1239 | |
---|
1240 | for (b = 0, |
---|
1241 | group = bdbuf_cache.groups, |
---|
1242 | bd = bdbuf_cache.bds; |
---|
1243 | b < bdbuf_cache.group_count; |
---|
1244 | b++, |
---|
1245 | group++, |
---|
1246 | bd += bdbuf_cache.max_bds_per_group) |
---|
1247 | { |
---|
1248 | group->bds_per_group = bdbuf_cache.max_bds_per_group; |
---|
1249 | group->users = 0; |
---|
1250 | group->bdbuf = bd; |
---|
1251 | } |
---|
1252 | |
---|
1253 | /* |
---|
1254 | * Create and start swapout task. This task will create and manage the worker |
---|
1255 | * threads. |
---|
1256 | */ |
---|
1257 | bdbuf_cache.swapout_enabled = true; |
---|
1258 | |
---|
1259 | sc = rtems_task_create (rtems_build_name('B', 'S', 'W', 'P'), |
---|
1260 | (bdbuf_config.swapout_priority ? |
---|
1261 | bdbuf_config.swapout_priority : |
---|
1262 | RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT), |
---|
1263 | SWAPOUT_TASK_STACK_SIZE, |
---|
1264 | RTEMS_PREEMPT | RTEMS_NO_TIMESLICE | RTEMS_NO_ASR, |
---|
1265 | RTEMS_LOCAL | RTEMS_NO_FLOATING_POINT, |
---|
1266 | &bdbuf_cache.swapout); |
---|
1267 | if (sc != RTEMS_SUCCESSFUL) |
---|
1268 | { |
---|
1269 | free (bdbuf_cache.buffers); |
---|
1270 | free (bdbuf_cache.groups); |
---|
1271 | free (bdbuf_cache.bds); |
---|
1272 | rtems_semaphore_delete (bdbuf_cache.transfer); |
---|
1273 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1274 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1275 | rtems_bdbuf_unlock_cache (); |
---|
1276 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1277 | bdbuf_cache.initialised = false; |
---|
1278 | return sc; |
---|
1279 | } |
---|
1280 | |
---|
1281 | sc = rtems_task_start (bdbuf_cache.swapout, |
---|
1282 | rtems_bdbuf_swapout_task, |
---|
1283 | (rtems_task_argument) &bdbuf_cache); |
---|
1284 | if (sc != RTEMS_SUCCESSFUL) |
---|
1285 | { |
---|
1286 | rtems_task_delete (bdbuf_cache.swapout); |
---|
1287 | free (bdbuf_cache.buffers); |
---|
1288 | free (bdbuf_cache.groups); |
---|
1289 | free (bdbuf_cache.bds); |
---|
1290 | rtems_semaphore_delete (bdbuf_cache.transfer); |
---|
1291 | rtems_semaphore_delete (bdbuf_cache.access); |
---|
1292 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1293 | rtems_bdbuf_unlock_cache (); |
---|
1294 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1295 | bdbuf_cache.initialised = false; |
---|
1296 | return sc; |
---|
1297 | } |
---|
1298 | |
---|
1299 | rtems_bdbuf_unlock_cache (); |
---|
1300 | |
---|
1301 | return RTEMS_SUCCESSFUL; |
---|
1302 | } |
---|
1303 | |
---|
1304 | /** |
---|
1305 | * Get a buffer for this device and block. This function returns a buffer once |
---|
1306 | * placed into the AVL tree. If no buffer is available and it is not a read |
---|
1307 | * ahead request and no buffers are waiting to the written to disk wait until a |
---|
1308 | * buffer is available. If buffers are waiting to be written to disk and none |
---|
1309 | * are available expire the hold timer's of the queued buffers and wake the |
---|
1310 | * swap out task. If the buffer is for a read ahead transfer return NULL if |
---|
1311 | * there are no buffers available or the buffer is already in the cache. |
---|
1312 | * |
---|
1313 | * The AVL tree of buffers for the cache is searched and if not found obtain a |
---|
1314 | * buffer and insert it into the AVL tree. Buffers are first obtained from the |
---|
1315 | * ready list until all empty/ready buffers are used. Once all buffers are in |
---|
1316 | * use the LRU list is searched for a buffer of the same group size or a group |
---|
1317 | * that has no active buffers in use. A buffer taken from the LRU list is |
---|
1318 | * removed from the AVL tree and assigned the new block number. The ready or |
---|
1319 | * LRU list buffer is initialised to this device and block. If no buffers are |
---|
1320 | * available due to the ready and LRU lists being empty a check is made of the |
---|
1321 | * modified list. Buffers may be queued waiting for the hold timer to |
---|
1322 | * expire. These buffers should be written to disk and returned to the LRU list |
---|
1323 | * where they can be used. If buffers are on the modified list the max. write |
---|
1324 | * block size of buffers have their hold timer's expired and the swap out task |
---|
1325 | * woken. The caller then blocks on the waiting semaphore and counter. When |
---|
1326 | * buffers return from the upper layers (access) or lower driver (transfer) the |
---|
1327 | * blocked caller task is woken and this procedure is repeated. The repeat |
---|
1328 | * handles a case of a another thread pre-empting getting a buffer first and |
---|
1329 | * adding it to the AVL tree. |
---|
1330 | * |
---|
1331 | * A buffer located in the AVL tree means it is already in the cache and maybe |
---|
1332 | * in use somewhere. The buffer can be either: |
---|
1333 | * |
---|
1334 | * # Cached. Not being accessed or part of a media transfer. |
---|
1335 | * # Access or modifed access. Is with an upper layer being accessed. |
---|
1336 | * # Transfer. Is with the driver and part of a media transfer. |
---|
1337 | * |
---|
1338 | * If cached we assign the new state, extract it from any list it maybe part of |
---|
1339 | * and return to the user. |
---|
1340 | * |
---|
1341 | * This function assumes the cache the buffer is being taken from is locked and |
---|
1342 | * it will make sure the cache is locked when it returns. The cache will be |
---|
1343 | * unlocked if the call could block. |
---|
1344 | * |
---|
1345 | * Variable sized buffer is handled by groups. A group is the size of the |
---|
1346 | * maximum buffer that can be allocated. The group can size in multiples of the |
---|
1347 | * minimum buffer size where the mulitples are 1,2,4,8, etc. If the buffer is |
---|
1348 | * found in the AVL tree the number of BDs in the group is check and if |
---|
1349 | * different the buffer size for the block has changed. The buffer needs to be |
---|
1350 | * invalidated. |
---|
1351 | * |
---|
1352 | * @param dd The disk device. Has the configured block size. |
---|
1353 | * @param bds_per_group The number of BDs in a group for this block. |
---|
1354 | * @param block Absolute media block number for the device |
---|
1355 | * @param read_ahead The get is for a read ahead buffer if true |
---|
1356 | * @return RTEMS status code (if operation completed successfully or error |
---|
1357 | * code if error is occured) |
---|
1358 | */ |
---|
1359 | static rtems_bdbuf_buffer* |
---|
1360 | rtems_bdbuf_get_buffer (rtems_disk_device* dd, |
---|
1361 | size_t bds_per_group, |
---|
1362 | rtems_blkdev_bnum block, |
---|
1363 | bool read_ahead) |
---|
1364 | { |
---|
1365 | dev_t device = dd->dev; |
---|
1366 | rtems_bdbuf_buffer* bd; |
---|
1367 | bool available; |
---|
1368 | |
---|
1369 | /* |
---|
1370 | * Loop until we get a buffer. Under load we could find no buffers are |
---|
1371 | * available requiring this task to wait until some become available before |
---|
1372 | * proceeding. There is no timeout. If this call is to block and the buffer |
---|
1373 | * is for a read ahead buffer return NULL. The read ahead is nice but not |
---|
1374 | * that important. |
---|
1375 | * |
---|
1376 | * The search procedure is repeated as another thread could have pre-empted |
---|
1377 | * us while we waited for a buffer, obtained an empty buffer and loaded the |
---|
1378 | * AVL tree with the one we are after. In this case we move down and wait for |
---|
1379 | * the buffer to return to the cache. |
---|
1380 | */ |
---|
1381 | do |
---|
1382 | { |
---|
1383 | /* |
---|
1384 | * Search for buffer descriptor for this dev/block key. |
---|
1385 | */ |
---|
1386 | bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, device, block); |
---|
1387 | |
---|
1388 | /* |
---|
1389 | * No buffer in the cache for this block. We need to obtain a buffer and |
---|
1390 | * this means take a buffer that is ready to use. If all buffers are in use |
---|
1391 | * take the least recently used buffer. If there are none then the cache is |
---|
1392 | * empty. All the buffers are either queued to be written to disk or with |
---|
1393 | * the user. We cannot do much with the buffers with the user how-ever with |
---|
1394 | * the modified buffers waiting to be written to disk flush the maximum |
---|
1395 | * number transfered in a block to disk. After this all that can be done is |
---|
1396 | * to wait for a buffer to return to the cache. |
---|
1397 | */ |
---|
1398 | if (!bd) |
---|
1399 | { |
---|
1400 | /* |
---|
1401 | * Assign new buffer descriptor from the ready list if one is present. If |
---|
1402 | * the ready queue is empty get the oldest buffer from LRU list. If the |
---|
1403 | * LRU list is empty there are no available buffers check the modified |
---|
1404 | * list. |
---|
1405 | */ |
---|
1406 | bd = rtems_bdbuf_get_next_bd (bds_per_group, &bdbuf_cache.ready); |
---|
1407 | |
---|
1408 | if (!bd) |
---|
1409 | { |
---|
1410 | /* |
---|
1411 | * No unused or read-ahead buffers. |
---|
1412 | * |
---|
1413 | * If this is a read ahead buffer just return. No need to place further |
---|
1414 | * pressure on the cache by reading something that may be needed when |
---|
1415 | * we have data in the cache that was needed and may still be in the |
---|
1416 | * future. |
---|
1417 | */ |
---|
1418 | if (read_ahead) |
---|
1419 | return NULL; |
---|
1420 | |
---|
1421 | /* |
---|
1422 | * Check the LRU list. |
---|
1423 | */ |
---|
1424 | bd = rtems_bdbuf_get_next_bd (bds_per_group, &bdbuf_cache.lru); |
---|
1425 | |
---|
1426 | if (bd) |
---|
1427 | { |
---|
1428 | /* |
---|
1429 | * Remove the buffer from the AVL tree. |
---|
1430 | */ |
---|
1431 | if (rtems_bdbuf_avl_remove (&bdbuf_cache.tree, bd) != 0) |
---|
1432 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1433 | } |
---|
1434 | else |
---|
1435 | { |
---|
1436 | /* |
---|
1437 | * If there are buffers on the modified list expire the hold timer |
---|
1438 | * and wake the swap out task then wait else just go and wait. |
---|
1439 | * |
---|
1440 | * The check for an empty list is made so the swapper is only woken |
---|
1441 | * when if timers are changed. |
---|
1442 | */ |
---|
1443 | if (!rtems_chain_is_empty (&bdbuf_cache.modified)) |
---|
1444 | { |
---|
1445 | rtems_chain_node* node = rtems_chain_first (&bdbuf_cache.modified); |
---|
1446 | uint32_t write_blocks = 0; |
---|
1447 | |
---|
1448 | while ((write_blocks < bdbuf_config.max_write_blocks) && |
---|
1449 | !rtems_chain_is_tail (&bdbuf_cache.modified, node)) |
---|
1450 | { |
---|
1451 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
1452 | bd->hold_timer = 0; |
---|
1453 | write_blocks++; |
---|
1454 | node = rtems_chain_next (node); |
---|
1455 | } |
---|
1456 | |
---|
1457 | rtems_bdbuf_wake_swapper (); |
---|
1458 | } |
---|
1459 | |
---|
1460 | /* |
---|
1461 | * Wait for a buffer to be returned to the cache. The buffer will be |
---|
1462 | * placed on the LRU list. |
---|
1463 | */ |
---|
1464 | rtems_bdbuf_wait (&bdbuf_cache.waiting, &bdbuf_cache.wait_waiters); |
---|
1465 | } |
---|
1466 | } |
---|
1467 | else |
---|
1468 | { |
---|
1469 | /* |
---|
1470 | * We have a new buffer for this block. |
---|
1471 | */ |
---|
1472 | if ((bd->state != RTEMS_BDBUF_STATE_EMPTY) && |
---|
1473 | (bd->state != RTEMS_BDBUF_STATE_READ_AHEAD)) |
---|
1474 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1475 | |
---|
1476 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
1477 | { |
---|
1478 | if (rtems_bdbuf_avl_remove (&bdbuf_cache.tree, bd) != 0) |
---|
1479 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1480 | } |
---|
1481 | } |
---|
1482 | |
---|
1483 | if (bd) |
---|
1484 | { |
---|
1485 | bd->dev = device; |
---|
1486 | bd->block = block; |
---|
1487 | bd->avl.left = NULL; |
---|
1488 | bd->avl.right = NULL; |
---|
1489 | bd->state = RTEMS_BDBUF_STATE_EMPTY; |
---|
1490 | bd->error = 0; |
---|
1491 | bd->waiters = 0; |
---|
1492 | |
---|
1493 | if (rtems_bdbuf_avl_insert (&bdbuf_cache.tree, bd) != 0) |
---|
1494 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1495 | |
---|
1496 | return bd; |
---|
1497 | } |
---|
1498 | } |
---|
1499 | else |
---|
1500 | { |
---|
1501 | /* |
---|
1502 | * We have the buffer for the block from the cache. Check if the buffer |
---|
1503 | * in the cache is the same size and the requested size we are after. |
---|
1504 | */ |
---|
1505 | if (bd->group->bds_per_group != bds_per_group) |
---|
1506 | { |
---|
1507 | bd->state = RTEMS_BDBUF_STATE_EMPTY; |
---|
1508 | rtems_chain_extract (&bd->link); |
---|
1509 | rtems_chain_prepend (&bdbuf_cache.ready, &bd->link); |
---|
1510 | bd = NULL; |
---|
1511 | } |
---|
1512 | } |
---|
1513 | } |
---|
1514 | while (!bd); |
---|
1515 | |
---|
1516 | /* |
---|
1517 | * If the buffer is for read ahead and it exists in the AVL cache or is being |
---|
1518 | * accessed or being transfered then return NULL. |
---|
1519 | */ |
---|
1520 | if (read_ahead) |
---|
1521 | return NULL; |
---|
1522 | |
---|
1523 | /* |
---|
1524 | * Loop waiting for the buffer to enter the cached state. If the buffer is in |
---|
1525 | * the access or transfer state then wait until it is not. |
---|
1526 | */ |
---|
1527 | available = false; |
---|
1528 | while (!available) |
---|
1529 | { |
---|
1530 | switch (bd->state) |
---|
1531 | { |
---|
1532 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1533 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1534 | case RTEMS_BDBUF_STATE_READ_AHEAD: |
---|
1535 | available = true; |
---|
1536 | break; |
---|
1537 | |
---|
1538 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
1539 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
1540 | bd->waiters++; |
---|
1541 | rtems_bdbuf_wait (&bdbuf_cache.access, |
---|
1542 | &bdbuf_cache.access_waiters); |
---|
1543 | bd->waiters--; |
---|
1544 | break; |
---|
1545 | |
---|
1546 | case RTEMS_BDBUF_STATE_SYNC: |
---|
1547 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
1548 | bd->waiters++; |
---|
1549 | rtems_bdbuf_wait (&bdbuf_cache.transfer, |
---|
1550 | &bdbuf_cache.transfer_waiters); |
---|
1551 | bd->waiters--; |
---|
1552 | break; |
---|
1553 | |
---|
1554 | default: |
---|
1555 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1556 | } |
---|
1557 | } |
---|
1558 | |
---|
1559 | /* |
---|
1560 | * Buffer is linked to the LRU, modifed, or sync lists. Remove it from there. |
---|
1561 | */ |
---|
1562 | rtems_chain_extract (&bd->link); |
---|
1563 | |
---|
1564 | return bd; |
---|
1565 | } |
---|
1566 | |
---|
1567 | rtems_status_code |
---|
1568 | rtems_bdbuf_get (dev_t device, |
---|
1569 | rtems_blkdev_bnum block, |
---|
1570 | rtems_bdbuf_buffer** bdp) |
---|
1571 | { |
---|
1572 | rtems_disk_device* dd; |
---|
1573 | rtems_bdbuf_buffer* bd; |
---|
1574 | size_t bds_per_group; |
---|
1575 | |
---|
1576 | if (!bdbuf_cache.initialised) |
---|
1577 | return RTEMS_NOT_CONFIGURED; |
---|
1578 | |
---|
1579 | /* |
---|
1580 | * Do not hold the cache lock when obtaining the disk table. |
---|
1581 | */ |
---|
1582 | dd = rtems_disk_obtain (device); |
---|
1583 | if (!dd) |
---|
1584 | return RTEMS_INVALID_ID; |
---|
1585 | |
---|
1586 | if (block >= dd->size) |
---|
1587 | { |
---|
1588 | rtems_disk_release (dd); |
---|
1589 | return RTEMS_INVALID_ADDRESS; |
---|
1590 | } |
---|
1591 | |
---|
1592 | bds_per_group = rtems_bdbuf_bds_per_group (dd->block_size); |
---|
1593 | if (!bds_per_group) |
---|
1594 | { |
---|
1595 | rtems_disk_release (dd); |
---|
1596 | return RTEMS_INVALID_NUMBER; |
---|
1597 | } |
---|
1598 | |
---|
1599 | rtems_bdbuf_lock_cache (); |
---|
1600 | |
---|
1601 | #if RTEMS_BDBUF_TRACE |
---|
1602 | /* Print the block index relative to the physical disk */ |
---|
1603 | rtems_bdbuf_printf ("get: %d (dev = %08x)\n", block + dd->start, device); |
---|
1604 | #endif |
---|
1605 | |
---|
1606 | bd = rtems_bdbuf_get_buffer (dd, bds_per_group, block + dd->start, false); |
---|
1607 | |
---|
1608 | if (bd->state == RTEMS_BDBUF_STATE_MODIFIED) |
---|
1609 | bd->state = RTEMS_BDBUF_STATE_ACCESS_MODIFIED; |
---|
1610 | else |
---|
1611 | bd->state = RTEMS_BDBUF_STATE_ACCESS; |
---|
1612 | |
---|
1613 | rtems_bdbuf_unlock_cache (); |
---|
1614 | |
---|
1615 | rtems_disk_release(dd); |
---|
1616 | |
---|
1617 | *bdp = bd; |
---|
1618 | |
---|
1619 | return RTEMS_SUCCESSFUL; |
---|
1620 | } |
---|
1621 | |
---|
1622 | /** |
---|
1623 | * Call back handler called by the low level driver when the transfer has |
---|
1624 | * completed. This function may be invoked from interrupt handler. |
---|
1625 | * |
---|
1626 | * @param arg Arbitrary argument specified in block device request |
---|
1627 | * structure (in this case - pointer to the appropriate |
---|
1628 | * block device request structure). |
---|
1629 | * @param status I/O completion status |
---|
1630 | * @param error errno error code if status != RTEMS_SUCCESSFUL |
---|
1631 | */ |
---|
1632 | static void |
---|
1633 | rtems_bdbuf_read_done (void* arg, rtems_status_code status, int error) |
---|
1634 | { |
---|
1635 | rtems_blkdev_request* req = (rtems_blkdev_request*) arg; |
---|
1636 | |
---|
1637 | req->error = error; |
---|
1638 | req->status = status; |
---|
1639 | |
---|
1640 | rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
1641 | } |
---|
1642 | |
---|
1643 | rtems_status_code |
---|
1644 | rtems_bdbuf_read (dev_t device, |
---|
1645 | rtems_blkdev_bnum block, |
---|
1646 | rtems_bdbuf_buffer** bdp) |
---|
1647 | { |
---|
1648 | rtems_disk_device* dd; |
---|
1649 | rtems_bdbuf_buffer* bd = NULL; |
---|
1650 | uint32_t read_ahead_count; |
---|
1651 | rtems_blkdev_request* req; |
---|
1652 | size_t bds_per_group; |
---|
1653 | |
---|
1654 | if (!bdbuf_cache.initialised) |
---|
1655 | return RTEMS_NOT_CONFIGURED; |
---|
1656 | |
---|
1657 | /* |
---|
1658 | * @todo This type of request structure is wrong and should be removed. |
---|
1659 | */ |
---|
1660 | #define bdbuf_alloc(size) __builtin_alloca (size) |
---|
1661 | |
---|
1662 | req = bdbuf_alloc (sizeof (rtems_blkdev_request) + |
---|
1663 | (sizeof ( rtems_blkdev_sg_buffer) * |
---|
1664 | rtems_bdbuf_configuration.max_read_ahead_blocks)); |
---|
1665 | |
---|
1666 | /* |
---|
1667 | * Do not hold the cache lock when obtaining the disk table. |
---|
1668 | */ |
---|
1669 | dd = rtems_disk_obtain (device); |
---|
1670 | if (!dd) |
---|
1671 | return RTEMS_INVALID_ID; |
---|
1672 | |
---|
1673 | if (block >= dd->size) { |
---|
1674 | rtems_disk_release(dd); |
---|
1675 | return RTEMS_INVALID_NUMBER; |
---|
1676 | } |
---|
1677 | |
---|
1678 | bds_per_group = rtems_bdbuf_bds_per_group (dd->block_size); |
---|
1679 | if (!bds_per_group) |
---|
1680 | { |
---|
1681 | rtems_disk_release (dd); |
---|
1682 | return RTEMS_INVALID_NUMBER; |
---|
1683 | } |
---|
1684 | |
---|
1685 | #if RTEMS_BDBUF_TRACE |
---|
1686 | /* Print the block index relative to the physical disk */ |
---|
1687 | rtems_bdbuf_printf ("read: %d (dev = %08x)\n", block + dd->start, device); |
---|
1688 | #endif |
---|
1689 | |
---|
1690 | req->bufnum = 0; |
---|
1691 | |
---|
1692 | /* |
---|
1693 | * Read the block plus the required number of blocks ahead. The number of |
---|
1694 | * blocks to read ahead is configured by the user and limited by the size of |
---|
1695 | * the disk or reaching a read ahead block that is also cached. |
---|
1696 | * |
---|
1697 | * Limit the blocks read by the size of the disk. |
---|
1698 | */ |
---|
1699 | if ((rtems_bdbuf_configuration.max_read_ahead_blocks + block) < dd->size) |
---|
1700 | read_ahead_count = rtems_bdbuf_configuration.max_read_ahead_blocks; |
---|
1701 | else |
---|
1702 | read_ahead_count = dd->size - block; |
---|
1703 | |
---|
1704 | rtems_bdbuf_lock_cache (); |
---|
1705 | |
---|
1706 | while (req->bufnum < read_ahead_count) |
---|
1707 | { |
---|
1708 | /* |
---|
1709 | * Get the buffer for the requested block. If the block is cached then |
---|
1710 | * return it. If it is not cached transfer the block from the disk media |
---|
1711 | * into memory. |
---|
1712 | * |
---|
1713 | * We need to clean up any buffers allocated and not passed back to the |
---|
1714 | * caller. |
---|
1715 | */ |
---|
1716 | bd = rtems_bdbuf_get_buffer (dd, bds_per_group, |
---|
1717 | block + dd->start + req->bufnum, |
---|
1718 | req->bufnum == 0 ? false : true); |
---|
1719 | |
---|
1720 | /* |
---|
1721 | * Read ahead buffer is in the cache or none available. Read what we |
---|
1722 | * can. |
---|
1723 | */ |
---|
1724 | if (!bd) |
---|
1725 | break; |
---|
1726 | |
---|
1727 | /* |
---|
1728 | * Is the block we are interested in the cache ? |
---|
1729 | */ |
---|
1730 | if ((bd->state == RTEMS_BDBUF_STATE_CACHED) || |
---|
1731 | (bd->state == RTEMS_BDBUF_STATE_MODIFIED)) |
---|
1732 | break; |
---|
1733 | |
---|
1734 | bd->state = RTEMS_BDBUF_STATE_TRANSFER; |
---|
1735 | bd->error = 0; |
---|
1736 | |
---|
1737 | /* |
---|
1738 | * @todo The use of these req blocks is not a great design. The req is a |
---|
1739 | * struct with a single 'bufs' declared in the req struct and the |
---|
1740 | * others are added in the outer level struct. This relies on the |
---|
1741 | * structs joining as a single array and that assumes the compiler |
---|
1742 | * packs the structs. Why not just place on a list ? The BD has a |
---|
1743 | * node that can be used. |
---|
1744 | */ |
---|
1745 | req->bufs[req->bufnum].user = bd; |
---|
1746 | req->bufs[req->bufnum].block = bd->block; |
---|
1747 | req->bufs[req->bufnum].length = dd->block_size; |
---|
1748 | req->bufs[req->bufnum].buffer = bd->buffer; |
---|
1749 | req->bufnum++; |
---|
1750 | } |
---|
1751 | |
---|
1752 | /* |
---|
1753 | * Transfer any requested buffers. If the request count is 0 we have found |
---|
1754 | * the block in the cache so return it. |
---|
1755 | */ |
---|
1756 | if (req->bufnum) |
---|
1757 | { |
---|
1758 | /* |
---|
1759 | * Unlock the cache. We have the buffer for the block and it will be in the |
---|
1760 | * access or transfer state. We may also have a number of read ahead blocks |
---|
1761 | * if we need to transfer data. At this point any other threads can gain |
---|
1762 | * access to the cache and if they are after any of the buffers we have |
---|
1763 | * they will block and be woken when the buffer is returned to the cache. |
---|
1764 | * |
---|
1765 | * If a transfer is needed the I/O operation will occur with pre-emption |
---|
1766 | * enabled and the cache unlocked. This is a change to the previous version |
---|
1767 | * of the bdbuf code. |
---|
1768 | */ |
---|
1769 | rtems_event_set out; |
---|
1770 | int result; |
---|
1771 | uint32_t b; |
---|
1772 | |
---|
1773 | /* |
---|
1774 | * Flush any events. |
---|
1775 | */ |
---|
1776 | rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
1777 | RTEMS_EVENT_ALL | RTEMS_NO_WAIT, |
---|
1778 | 0, &out); |
---|
1779 | |
---|
1780 | rtems_bdbuf_unlock_cache (); |
---|
1781 | |
---|
1782 | req->req = RTEMS_BLKDEV_REQ_READ; |
---|
1783 | req->req_done = rtems_bdbuf_read_done; |
---|
1784 | req->done_arg = req; |
---|
1785 | req->io_task = rtems_task_self (); |
---|
1786 | req->status = RTEMS_RESOURCE_IN_USE; |
---|
1787 | req->error = 0; |
---|
1788 | |
---|
1789 | result = dd->ioctl (dd->phys_dev->dev, RTEMS_BLKIO_REQUEST, req); |
---|
1790 | |
---|
1791 | /* |
---|
1792 | * Inspection of the DOS FS code shows the result from this function is |
---|
1793 | * handled and a buffer must be returned. |
---|
1794 | */ |
---|
1795 | if (result < 0) |
---|
1796 | { |
---|
1797 | req->error = errno; |
---|
1798 | req->status = RTEMS_IO_ERROR; |
---|
1799 | } |
---|
1800 | else |
---|
1801 | { |
---|
1802 | rtems_status_code sc; |
---|
1803 | |
---|
1804 | sc = rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
1805 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
1806 | 0, &out); |
---|
1807 | |
---|
1808 | if (sc != RTEMS_SUCCESSFUL) |
---|
1809 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
1810 | } |
---|
1811 | |
---|
1812 | rtems_bdbuf_lock_cache (); |
---|
1813 | |
---|
1814 | for (b = 1; b < req->bufnum; b++) |
---|
1815 | { |
---|
1816 | bd = req->bufs[b].user; |
---|
1817 | bd->error = req->error; |
---|
1818 | bd->state = RTEMS_BDBUF_STATE_READ_AHEAD; |
---|
1819 | rtems_bdbuf_release (bd); |
---|
1820 | } |
---|
1821 | |
---|
1822 | bd = req->bufs[0].user; |
---|
1823 | } |
---|
1824 | |
---|
1825 | /* |
---|
1826 | * The data for this block is cached in the buffer. |
---|
1827 | */ |
---|
1828 | if (bd->state == RTEMS_BDBUF_STATE_MODIFIED) |
---|
1829 | bd->state = RTEMS_BDBUF_STATE_ACCESS_MODIFIED; |
---|
1830 | else |
---|
1831 | bd->state = RTEMS_BDBUF_STATE_ACCESS; |
---|
1832 | |
---|
1833 | rtems_bdbuf_unlock_cache (); |
---|
1834 | rtems_disk_release (dd); |
---|
1835 | |
---|
1836 | *bdp = bd; |
---|
1837 | |
---|
1838 | return RTEMS_SUCCESSFUL; |
---|
1839 | } |
---|
1840 | |
---|
1841 | rtems_status_code |
---|
1842 | rtems_bdbuf_release (rtems_bdbuf_buffer* bd) |
---|
1843 | { |
---|
1844 | if (!bdbuf_cache.initialised) |
---|
1845 | return RTEMS_NOT_CONFIGURED; |
---|
1846 | |
---|
1847 | if (bd == NULL) |
---|
1848 | return RTEMS_INVALID_ADDRESS; |
---|
1849 | |
---|
1850 | rtems_bdbuf_lock_cache (); |
---|
1851 | |
---|
1852 | #if RTEMS_BDBUF_TRACE |
---|
1853 | rtems_bdbuf_printf ("release: %d\n", bd->block); |
---|
1854 | #endif |
---|
1855 | |
---|
1856 | if (bd->state == RTEMS_BDBUF_STATE_ACCESS_MODIFIED) |
---|
1857 | { |
---|
1858 | rtems_bdbuf_append_modified (bd); |
---|
1859 | } |
---|
1860 | else |
---|
1861 | { |
---|
1862 | /* |
---|
1863 | * If this is a read ahead buffer place the ready queue. Buffers are taken |
---|
1864 | * from here first. If we prepend then get from the queue the buffers |
---|
1865 | * furthermost from the read buffer will be used. |
---|
1866 | */ |
---|
1867 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
1868 | rtems_chain_prepend (&bdbuf_cache.ready, &bd->link); |
---|
1869 | else |
---|
1870 | { |
---|
1871 | bd->state = RTEMS_BDBUF_STATE_CACHED; |
---|
1872 | rtems_chain_append (&bdbuf_cache.lru, &bd->link); |
---|
1873 | } |
---|
1874 | |
---|
1875 | /* |
---|
1876 | * One less user for the group of bds. |
---|
1877 | */ |
---|
1878 | bd->group->users--; |
---|
1879 | } |
---|
1880 | |
---|
1881 | /* |
---|
1882 | * If there are threads waiting to access the buffer wake them. Wake any |
---|
1883 | * waiters if this is the first buffer to placed back onto the queue. |
---|
1884 | */ |
---|
1885 | if (bd->waiters) |
---|
1886 | rtems_bdbuf_wake (bdbuf_cache.access, &bdbuf_cache.access_waiters); |
---|
1887 | else |
---|
1888 | { |
---|
1889 | if (bd->state == RTEMS_BDBUF_STATE_READ_AHEAD) |
---|
1890 | { |
---|
1891 | if (rtems_chain_has_only_one_node (&bdbuf_cache.ready)) |
---|
1892 | rtems_bdbuf_wake (bdbuf_cache.waiting, &bdbuf_cache.wait_waiters); |
---|
1893 | } |
---|
1894 | else |
---|
1895 | { |
---|
1896 | if (rtems_chain_has_only_one_node (&bdbuf_cache.lru)) |
---|
1897 | rtems_bdbuf_wake (bdbuf_cache.waiting, &bdbuf_cache.wait_waiters); |
---|
1898 | } |
---|
1899 | } |
---|
1900 | |
---|
1901 | rtems_bdbuf_unlock_cache (); |
---|
1902 | |
---|
1903 | return RTEMS_SUCCESSFUL; |
---|
1904 | } |
---|
1905 | |
---|
1906 | rtems_status_code |
---|
1907 | rtems_bdbuf_release_modified (rtems_bdbuf_buffer* bd) |
---|
1908 | { |
---|
1909 | if (!bdbuf_cache.initialised) |
---|
1910 | return RTEMS_NOT_CONFIGURED; |
---|
1911 | |
---|
1912 | if (!bd) |
---|
1913 | return RTEMS_INVALID_ADDRESS; |
---|
1914 | |
---|
1915 | rtems_bdbuf_lock_cache (); |
---|
1916 | |
---|
1917 | #if RTEMS_BDBUF_TRACE |
---|
1918 | rtems_bdbuf_printf ("release modified: %d\n", bd->block); |
---|
1919 | #endif |
---|
1920 | |
---|
1921 | bd->hold_timer = rtems_bdbuf_configuration.swap_block_hold; |
---|
1922 | |
---|
1923 | rtems_bdbuf_append_modified (bd); |
---|
1924 | |
---|
1925 | if (bd->waiters) |
---|
1926 | rtems_bdbuf_wake (bdbuf_cache.access, &bdbuf_cache.access_waiters); |
---|
1927 | |
---|
1928 | rtems_bdbuf_unlock_cache (); |
---|
1929 | |
---|
1930 | return RTEMS_SUCCESSFUL; |
---|
1931 | } |
---|
1932 | |
---|
1933 | rtems_status_code |
---|
1934 | rtems_bdbuf_sync (rtems_bdbuf_buffer* bd) |
---|
1935 | { |
---|
1936 | bool available; |
---|
1937 | |
---|
1938 | #if RTEMS_BDBUF_TRACE |
---|
1939 | rtems_bdbuf_printf ("sync: %d\n", bd->block); |
---|
1940 | #endif |
---|
1941 | |
---|
1942 | if (!bdbuf_cache.initialised) |
---|
1943 | return RTEMS_NOT_CONFIGURED; |
---|
1944 | |
---|
1945 | if (!bd) |
---|
1946 | return RTEMS_INVALID_ADDRESS; |
---|
1947 | |
---|
1948 | rtems_bdbuf_lock_cache (); |
---|
1949 | |
---|
1950 | bd->state = RTEMS_BDBUF_STATE_SYNC; |
---|
1951 | |
---|
1952 | rtems_chain_append (&bdbuf_cache.sync, &bd->link); |
---|
1953 | |
---|
1954 | rtems_bdbuf_wake_swapper (); |
---|
1955 | |
---|
1956 | available = false; |
---|
1957 | while (!available) |
---|
1958 | { |
---|
1959 | switch (bd->state) |
---|
1960 | { |
---|
1961 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1962 | case RTEMS_BDBUF_STATE_READ_AHEAD: |
---|
1963 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1964 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
1965 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
1966 | available = true; |
---|
1967 | break; |
---|
1968 | |
---|
1969 | case RTEMS_BDBUF_STATE_SYNC: |
---|
1970 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
1971 | bd->waiters++; |
---|
1972 | rtems_bdbuf_wait (&bdbuf_cache.transfer, &bdbuf_cache.transfer_waiters); |
---|
1973 | bd->waiters--; |
---|
1974 | break; |
---|
1975 | |
---|
1976 | default: |
---|
1977 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CONSISTENCY); |
---|
1978 | } |
---|
1979 | } |
---|
1980 | |
---|
1981 | rtems_bdbuf_unlock_cache (); |
---|
1982 | |
---|
1983 | return RTEMS_SUCCESSFUL; |
---|
1984 | } |
---|
1985 | |
---|
1986 | rtems_status_code |
---|
1987 | rtems_bdbuf_syncdev (dev_t dev) |
---|
1988 | { |
---|
1989 | rtems_disk_device* dd; |
---|
1990 | rtems_status_code sc; |
---|
1991 | rtems_event_set out; |
---|
1992 | |
---|
1993 | #if RTEMS_BDBUF_TRACE |
---|
1994 | rtems_bdbuf_printf ("syncdev: %08x\n", dev); |
---|
1995 | #endif |
---|
1996 | |
---|
1997 | if (!bdbuf_cache.initialised) |
---|
1998 | return RTEMS_NOT_CONFIGURED; |
---|
1999 | |
---|
2000 | /* |
---|
2001 | * Do not hold the cache lock when obtaining the disk table. |
---|
2002 | */ |
---|
2003 | dd = rtems_disk_obtain (dev); |
---|
2004 | if (!dd) |
---|
2005 | return RTEMS_INVALID_ID; |
---|
2006 | |
---|
2007 | /* |
---|
2008 | * Take the sync lock before locking the cache. Once we have the sync lock we |
---|
2009 | * can lock the cache. If another thread has the sync lock it will cause this |
---|
2010 | * thread to block until it owns the sync lock then it can own the cache. The |
---|
2011 | * sync lock can only be obtained with the cache unlocked. |
---|
2012 | */ |
---|
2013 | |
---|
2014 | rtems_bdbuf_lock_sync (); |
---|
2015 | rtems_bdbuf_lock_cache (); |
---|
2016 | |
---|
2017 | /* |
---|
2018 | * Set the cache to have a sync active for a specific device and let the swap |
---|
2019 | * out task know the id of the requester to wake when done. |
---|
2020 | * |
---|
2021 | * The swap out task will negate the sync active flag when no more buffers |
---|
2022 | * for the device are held on the "modified for sync" queues. |
---|
2023 | */ |
---|
2024 | bdbuf_cache.sync_active = true; |
---|
2025 | bdbuf_cache.sync_requester = rtems_task_self (); |
---|
2026 | bdbuf_cache.sync_device = dev; |
---|
2027 | |
---|
2028 | rtems_bdbuf_wake_swapper (); |
---|
2029 | rtems_bdbuf_unlock_cache (); |
---|
2030 | |
---|
2031 | sc = rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
2032 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
2033 | 0, &out); |
---|
2034 | |
---|
2035 | if (sc != RTEMS_SUCCESSFUL) |
---|
2036 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
2037 | |
---|
2038 | rtems_bdbuf_unlock_sync (); |
---|
2039 | |
---|
2040 | return rtems_disk_release (dd); |
---|
2041 | } |
---|
2042 | |
---|
2043 | /** |
---|
2044 | * Call back handler called by the low level driver when the transfer has |
---|
2045 | * completed. This function may be invoked from interrupt handler. |
---|
2046 | * |
---|
2047 | * @param arg Arbitrary argument specified in block device request |
---|
2048 | * structure (in this case - pointer to the appropriate |
---|
2049 | * block device request structure). |
---|
2050 | * @param status I/O completion status |
---|
2051 | * @param error errno error code if status != RTEMS_SUCCESSFUL |
---|
2052 | */ |
---|
2053 | static void |
---|
2054 | rtems_bdbuf_write_done(void *arg, rtems_status_code status, int error) |
---|
2055 | { |
---|
2056 | rtems_blkdev_request* req = (rtems_blkdev_request*) arg; |
---|
2057 | |
---|
2058 | req->error = error; |
---|
2059 | req->status = status; |
---|
2060 | |
---|
2061 | rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
2062 | } |
---|
2063 | |
---|
2064 | /** |
---|
2065 | * Swapout transfer to the driver. The driver will break this I/O into groups |
---|
2066 | * of consecutive write requests is multiple consecutive buffers are required |
---|
2067 | * by the driver. |
---|
2068 | * |
---|
2069 | * @param transfer The transfer transaction. |
---|
2070 | */ |
---|
2071 | static void |
---|
2072 | rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer) |
---|
2073 | { |
---|
2074 | rtems_disk_device* dd; |
---|
2075 | |
---|
2076 | #if RTEMS_BDBUF_TRACE |
---|
2077 | rtems_bdbuf_printf ("swapout transfer: %08x\n", transfer->dev); |
---|
2078 | #endif |
---|
2079 | |
---|
2080 | /* |
---|
2081 | * If there are buffers to transfer to the media transfer them. |
---|
2082 | */ |
---|
2083 | if (!rtems_chain_is_empty (&transfer->bds)) |
---|
2084 | { |
---|
2085 | /* |
---|
2086 | * Obtain the disk device. The cache's mutex has been released to avoid a |
---|
2087 | * dead lock. |
---|
2088 | */ |
---|
2089 | dd = rtems_disk_obtain (transfer->dev); |
---|
2090 | if (dd) |
---|
2091 | { |
---|
2092 | /* |
---|
2093 | * The last block number used when the driver only supports |
---|
2094 | * continuous blocks in a single request. |
---|
2095 | */ |
---|
2096 | uint32_t last_block = 0; |
---|
2097 | |
---|
2098 | /* |
---|
2099 | * Take as many buffers as configured and pass to the driver. Note, the |
---|
2100 | * API to the drivers has an array of buffers and if a chain was passed |
---|
2101 | * we could have just passed the list. If the driver API is updated it |
---|
2102 | * should be possible to make this change with little effect in this |
---|
2103 | * code. The array that is passed is broken in design and should be |
---|
2104 | * removed. Merging members of a struct into the first member is |
---|
2105 | * trouble waiting to happen. |
---|
2106 | */ |
---|
2107 | transfer->write_req->status = RTEMS_RESOURCE_IN_USE; |
---|
2108 | transfer->write_req->error = 0; |
---|
2109 | transfer->write_req->bufnum = 0; |
---|
2110 | |
---|
2111 | while (!rtems_chain_is_empty (&transfer->bds)) |
---|
2112 | { |
---|
2113 | rtems_bdbuf_buffer* bd = |
---|
2114 | (rtems_bdbuf_buffer*) rtems_chain_get (&transfer->bds); |
---|
2115 | |
---|
2116 | bool write = false; |
---|
2117 | |
---|
2118 | /* |
---|
2119 | * If the device only accepts sequential buffers and this is not the |
---|
2120 | * first buffer (the first is always sequential, and the buffer is not |
---|
2121 | * sequential then put the buffer back on the transfer chain and write |
---|
2122 | * the committed buffers. |
---|
2123 | */ |
---|
2124 | |
---|
2125 | #if RTEMS_BDBUF_TRACE |
---|
2126 | rtems_bdbuf_printf ("swapout write: bd:%d, bufnum:%d mode:%s\n", |
---|
2127 | bd->block, transfer->write_req->bufnum, |
---|
2128 | dd->phys_dev->capabilities & |
---|
2129 | RTEMS_BLKDEV_CAP_MULTISECTOR_CONT ? "MULIT" : "SCAT"); |
---|
2130 | #endif |
---|
2131 | |
---|
2132 | if ((dd->phys_dev->capabilities & RTEMS_BLKDEV_CAP_MULTISECTOR_CONT) && |
---|
2133 | transfer->write_req->bufnum && |
---|
2134 | (bd->block != (last_block + 1))) |
---|
2135 | { |
---|
2136 | rtems_chain_prepend (&transfer->bds, &bd->link); |
---|
2137 | write = true; |
---|
2138 | } |
---|
2139 | else |
---|
2140 | { |
---|
2141 | rtems_blkdev_sg_buffer* buf; |
---|
2142 | buf = &transfer->write_req->bufs[transfer->write_req->bufnum]; |
---|
2143 | transfer->write_req->bufnum++; |
---|
2144 | buf->user = bd; |
---|
2145 | buf->block = bd->block; |
---|
2146 | buf->length = dd->block_size; |
---|
2147 | buf->buffer = bd->buffer; |
---|
2148 | last_block = bd->block; |
---|
2149 | } |
---|
2150 | |
---|
2151 | /* |
---|
2152 | * Perform the transfer if there are no more buffers, or the transfer |
---|
2153 | * size has reached the configured max. value. |
---|
2154 | */ |
---|
2155 | |
---|
2156 | if (rtems_chain_is_empty (&transfer->bds) || |
---|
2157 | (transfer->write_req->bufnum >= rtems_bdbuf_configuration.max_write_blocks)) |
---|
2158 | write = true; |
---|
2159 | |
---|
2160 | if (write) |
---|
2161 | { |
---|
2162 | int result; |
---|
2163 | uint32_t b; |
---|
2164 | |
---|
2165 | #if RTEMS_BDBUF_TRACE |
---|
2166 | rtems_bdbuf_printf ("swapout write: writing bufnum:%d\n", |
---|
2167 | transfer->write_req->bufnum); |
---|
2168 | #endif |
---|
2169 | /* |
---|
2170 | * Perform the transfer. No cache locks, no preemption, only the disk |
---|
2171 | * device is being held. |
---|
2172 | */ |
---|
2173 | result = dd->phys_dev->ioctl (dd->phys_dev->dev, |
---|
2174 | RTEMS_BLKIO_REQUEST, transfer->write_req); |
---|
2175 | |
---|
2176 | if (result < 0) |
---|
2177 | { |
---|
2178 | rtems_bdbuf_lock_cache (); |
---|
2179 | |
---|
2180 | for (b = 0; b < transfer->write_req->bufnum; b++) |
---|
2181 | { |
---|
2182 | bd = transfer->write_req->bufs[b].user; |
---|
2183 | bd->state = RTEMS_BDBUF_STATE_MODIFIED; |
---|
2184 | bd->error = errno; |
---|
2185 | |
---|
2186 | /* |
---|
2187 | * Place back on the cache's modified queue and try again. |
---|
2188 | * |
---|
2189 | * @warning Not sure this is the best option but I do not know |
---|
2190 | * what else can be done. |
---|
2191 | */ |
---|
2192 | rtems_chain_append (&bdbuf_cache.modified, &bd->link); |
---|
2193 | } |
---|
2194 | } |
---|
2195 | else |
---|
2196 | { |
---|
2197 | rtems_status_code sc = 0; |
---|
2198 | rtems_event_set out; |
---|
2199 | |
---|
2200 | sc = rtems_event_receive (RTEMS_BDBUF_TRANSFER_SYNC, |
---|
2201 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
2202 | 0, &out); |
---|
2203 | |
---|
2204 | if (sc != RTEMS_SUCCESSFUL) |
---|
2205 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
2206 | |
---|
2207 | rtems_bdbuf_lock_cache (); |
---|
2208 | |
---|
2209 | for (b = 0; b < transfer->write_req->bufnum; b++) |
---|
2210 | { |
---|
2211 | bd = transfer->write_req->bufs[b].user; |
---|
2212 | bd->state = RTEMS_BDBUF_STATE_CACHED; |
---|
2213 | bd->error = 0; |
---|
2214 | bd->group->users--; |
---|
2215 | |
---|
2216 | rtems_chain_append (&bdbuf_cache.lru, &bd->link); |
---|
2217 | |
---|
2218 | if (bd->waiters) |
---|
2219 | rtems_bdbuf_wake (bdbuf_cache.transfer, &bdbuf_cache.transfer_waiters); |
---|
2220 | else |
---|
2221 | { |
---|
2222 | if (rtems_chain_has_only_one_node (&bdbuf_cache.lru)) |
---|
2223 | rtems_bdbuf_wake (bdbuf_cache.waiting, &bdbuf_cache.wait_waiters); |
---|
2224 | } |
---|
2225 | } |
---|
2226 | } |
---|
2227 | |
---|
2228 | rtems_bdbuf_unlock_cache (); |
---|
2229 | |
---|
2230 | transfer->write_req->status = RTEMS_RESOURCE_IN_USE; |
---|
2231 | transfer->write_req->error = 0; |
---|
2232 | transfer->write_req->bufnum = 0; |
---|
2233 | } |
---|
2234 | } |
---|
2235 | |
---|
2236 | rtems_disk_release (dd); |
---|
2237 | } |
---|
2238 | else |
---|
2239 | { |
---|
2240 | /* |
---|
2241 | * We have buffers but no device. Put the BDs back onto the |
---|
2242 | * ready queue and exit. |
---|
2243 | */ |
---|
2244 | /* @todo fixme */ |
---|
2245 | } |
---|
2246 | } |
---|
2247 | } |
---|
2248 | |
---|
2249 | /** |
---|
2250 | * Process the modified list of buffers. There is a sync or modified list that |
---|
2251 | * needs to be handled so we have a common function to do the work. |
---|
2252 | * |
---|
2253 | * @param dev The device to handle. If -1 no device is selected so select the |
---|
2254 | * device of the first buffer to be written to disk. |
---|
2255 | * @param chain The modified chain to process. |
---|
2256 | * @param transfer The chain to append buffers to be written too. |
---|
2257 | * @param sync_active If true this is a sync operation so expire all timers. |
---|
2258 | * @param update_timers If true update the timers. |
---|
2259 | * @param timer_delta It update_timers is true update the timers by this |
---|
2260 | * amount. |
---|
2261 | */ |
---|
2262 | static void |
---|
2263 | rtems_bdbuf_swapout_modified_processing (dev_t* dev, |
---|
2264 | rtems_chain_control* chain, |
---|
2265 | rtems_chain_control* transfer, |
---|
2266 | bool sync_active, |
---|
2267 | bool update_timers, |
---|
2268 | uint32_t timer_delta) |
---|
2269 | { |
---|
2270 | if (!rtems_chain_is_empty (chain)) |
---|
2271 | { |
---|
2272 | rtems_chain_node* node = rtems_chain_head (chain); |
---|
2273 | node = node->next; |
---|
2274 | |
---|
2275 | while (!rtems_chain_is_tail (chain, node)) |
---|
2276 | { |
---|
2277 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
2278 | |
---|
2279 | /* |
---|
2280 | * Check if the buffer's hold timer has reached 0. If a sync is active |
---|
2281 | * force all the timers to 0. |
---|
2282 | * |
---|
2283 | * @note Lots of sync requests will skew this timer. It should be based |
---|
2284 | * on TOD to be accurate. Does it matter ? |
---|
2285 | */ |
---|
2286 | if (sync_active) |
---|
2287 | bd->hold_timer = 0; |
---|
2288 | |
---|
2289 | if (bd->hold_timer) |
---|
2290 | { |
---|
2291 | if (update_timers) |
---|
2292 | { |
---|
2293 | if (bd->hold_timer > timer_delta) |
---|
2294 | bd->hold_timer -= timer_delta; |
---|
2295 | else |
---|
2296 | bd->hold_timer = 0; |
---|
2297 | } |
---|
2298 | |
---|
2299 | if (bd->hold_timer) |
---|
2300 | { |
---|
2301 | node = node->next; |
---|
2302 | continue; |
---|
2303 | } |
---|
2304 | } |
---|
2305 | |
---|
2306 | /* |
---|
2307 | * This assumes we can set dev_t to -1 which is just an |
---|
2308 | * assumption. Cannot use the transfer list being empty the sync dev |
---|
2309 | * calls sets the dev to use. |
---|
2310 | */ |
---|
2311 | if (*dev == (dev_t)-1) |
---|
2312 | *dev = bd->dev; |
---|
2313 | |
---|
2314 | if (bd->dev == *dev) |
---|
2315 | { |
---|
2316 | rtems_chain_node* next_node = node->next; |
---|
2317 | rtems_chain_node* tnode = rtems_chain_tail (transfer); |
---|
2318 | |
---|
2319 | /* |
---|
2320 | * The blocks on the transfer list are sorted in block order. This |
---|
2321 | * means multi-block transfers for drivers that require consecutive |
---|
2322 | * blocks perform better with sorted blocks and for real disks it may |
---|
2323 | * help lower head movement. |
---|
2324 | */ |
---|
2325 | |
---|
2326 | bd->state = RTEMS_BDBUF_STATE_TRANSFER; |
---|
2327 | |
---|
2328 | rtems_chain_extract (node); |
---|
2329 | |
---|
2330 | tnode = tnode->previous; |
---|
2331 | |
---|
2332 | while (node && !rtems_chain_is_head (transfer, tnode)) |
---|
2333 | { |
---|
2334 | rtems_bdbuf_buffer* tbd = (rtems_bdbuf_buffer*) tnode; |
---|
2335 | |
---|
2336 | if (bd->block > tbd->block) |
---|
2337 | { |
---|
2338 | rtems_chain_insert (tnode, node); |
---|
2339 | node = NULL; |
---|
2340 | } |
---|
2341 | else |
---|
2342 | tnode = tnode->previous; |
---|
2343 | } |
---|
2344 | |
---|
2345 | if (node) |
---|
2346 | rtems_chain_prepend (transfer, node); |
---|
2347 | |
---|
2348 | node = next_node; |
---|
2349 | } |
---|
2350 | else |
---|
2351 | { |
---|
2352 | node = node->next; |
---|
2353 | } |
---|
2354 | } |
---|
2355 | } |
---|
2356 | } |
---|
2357 | |
---|
2358 | /** |
---|
2359 | * Process the cache's modified buffers. Check the sync list first then the |
---|
2360 | * modified list extracting the buffers suitable to be written to disk. We have |
---|
2361 | * a device at a time. The task level loop will repeat this operation while |
---|
2362 | * there are buffers to be written. If the transfer fails place the buffers |
---|
2363 | * back on the modified list and try again later. The cache is unlocked while |
---|
2364 | * the buffers are being written to disk. |
---|
2365 | * |
---|
2366 | * @param timer_delta It update_timers is true update the timers by this |
---|
2367 | * amount. |
---|
2368 | * @param update_timers If true update the timers. |
---|
2369 | * @param transfer The transfer transaction data. |
---|
2370 | * |
---|
2371 | * @retval true Buffers where written to disk so scan again. |
---|
2372 | * @retval false No buffers where written to disk. |
---|
2373 | */ |
---|
2374 | static bool |
---|
2375 | rtems_bdbuf_swapout_processing (unsigned long timer_delta, |
---|
2376 | bool update_timers, |
---|
2377 | rtems_bdbuf_swapout_transfer* transfer) |
---|
2378 | { |
---|
2379 | rtems_bdbuf_swapout_worker* worker; |
---|
2380 | bool transfered_buffers = false; |
---|
2381 | |
---|
2382 | rtems_bdbuf_lock_cache (); |
---|
2383 | |
---|
2384 | /* |
---|
2385 | * If a sync is active do not use a worker because the current code does not |
---|
2386 | * cleaning up after. We need to know the buffers have been written when |
---|
2387 | * syncing to release sync lock and currently worker threads do not return to |
---|
2388 | * here. We do not know the worker is the last in a sequence of sync writes |
---|
2389 | * until after we have it running so we do not know to tell it to release the |
---|
2390 | * lock. The simplest solution is to get the main swap out task perform all |
---|
2391 | * sync operations. |
---|
2392 | */ |
---|
2393 | if (bdbuf_cache.sync_active) |
---|
2394 | worker = NULL; |
---|
2395 | else |
---|
2396 | { |
---|
2397 | worker = (rtems_bdbuf_swapout_worker*) |
---|
2398 | rtems_chain_get (&bdbuf_cache.swapout_workers); |
---|
2399 | if (worker) |
---|
2400 | transfer = &worker->transfer; |
---|
2401 | } |
---|
2402 | |
---|
2403 | rtems_chain_initialize_empty (&transfer->bds); |
---|
2404 | transfer->dev = -1; |
---|
2405 | |
---|
2406 | /* |
---|
2407 | * When the sync is for a device limit the sync to that device. If the sync |
---|
2408 | * is for a buffer handle process the devices in the order on the sync |
---|
2409 | * list. This means the dev is -1. |
---|
2410 | */ |
---|
2411 | if (bdbuf_cache.sync_active) |
---|
2412 | transfer->dev = bdbuf_cache.sync_device; |
---|
2413 | |
---|
2414 | /* |
---|
2415 | * If we have any buffers in the sync queue move them to the modified |
---|
2416 | * list. The first sync buffer will select the device we use. |
---|
2417 | */ |
---|
2418 | rtems_bdbuf_swapout_modified_processing (&transfer->dev, |
---|
2419 | &bdbuf_cache.sync, |
---|
2420 | &transfer->bds, |
---|
2421 | true, false, |
---|
2422 | timer_delta); |
---|
2423 | |
---|
2424 | /* |
---|
2425 | * Process the cache's modified list. |
---|
2426 | */ |
---|
2427 | rtems_bdbuf_swapout_modified_processing (&transfer->dev, |
---|
2428 | &bdbuf_cache.modified, |
---|
2429 | &transfer->bds, |
---|
2430 | bdbuf_cache.sync_active, |
---|
2431 | update_timers, |
---|
2432 | timer_delta); |
---|
2433 | |
---|
2434 | /* |
---|
2435 | * We have all the buffers that have been modified for this device so the |
---|
2436 | * cache can be unlocked because the state of each buffer has been set to |
---|
2437 | * TRANSFER. |
---|
2438 | */ |
---|
2439 | rtems_bdbuf_unlock_cache (); |
---|
2440 | |
---|
2441 | /* |
---|
2442 | * If there are buffers to transfer to the media transfer them. |
---|
2443 | */ |
---|
2444 | if (!rtems_chain_is_empty (&transfer->bds)) |
---|
2445 | { |
---|
2446 | if (worker) |
---|
2447 | { |
---|
2448 | rtems_status_code sc = rtems_event_send (worker->id, |
---|
2449 | RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
2450 | if (sc != RTEMS_SUCCESSFUL) |
---|
2451 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE); |
---|
2452 | } |
---|
2453 | else |
---|
2454 | { |
---|
2455 | rtems_bdbuf_swapout_write (transfer); |
---|
2456 | } |
---|
2457 | |
---|
2458 | transfered_buffers = true; |
---|
2459 | } |
---|
2460 | |
---|
2461 | if (bdbuf_cache.sync_active && !transfered_buffers) |
---|
2462 | { |
---|
2463 | rtems_id sync_requester; |
---|
2464 | rtems_bdbuf_lock_cache (); |
---|
2465 | sync_requester = bdbuf_cache.sync_requester; |
---|
2466 | bdbuf_cache.sync_active = false; |
---|
2467 | bdbuf_cache.sync_requester = 0; |
---|
2468 | rtems_bdbuf_unlock_cache (); |
---|
2469 | if (sync_requester) |
---|
2470 | rtems_event_send (sync_requester, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
2471 | } |
---|
2472 | |
---|
2473 | return transfered_buffers; |
---|
2474 | } |
---|
2475 | |
---|
2476 | /** |
---|
2477 | * Allocate the write request and initialise it for good measure. |
---|
2478 | * |
---|
2479 | * @return rtems_blkdev_request* The write reference memory. |
---|
2480 | */ |
---|
2481 | static rtems_blkdev_request* |
---|
2482 | rtems_bdbuf_swapout_writereq_alloc (void) |
---|
2483 | { |
---|
2484 | /* |
---|
2485 | * @note chrisj The rtems_blkdev_request and the array at the end is a hack. |
---|
2486 | * I am disappointment at finding code like this in RTEMS. The request should |
---|
2487 | * have been a rtems_chain_control. Simple, fast and less storage as the node |
---|
2488 | * is already part of the buffer structure. |
---|
2489 | */ |
---|
2490 | rtems_blkdev_request* write_req = |
---|
2491 | malloc (sizeof (rtems_blkdev_request) + |
---|
2492 | (rtems_bdbuf_configuration.max_write_blocks * |
---|
2493 | sizeof (rtems_blkdev_sg_buffer))); |
---|
2494 | |
---|
2495 | if (!write_req) |
---|
2496 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM); |
---|
2497 | |
---|
2498 | write_req->req = RTEMS_BLKDEV_REQ_WRITE; |
---|
2499 | write_req->req_done = rtems_bdbuf_write_done; |
---|
2500 | write_req->done_arg = write_req; |
---|
2501 | write_req->io_task = rtems_task_self (); |
---|
2502 | |
---|
2503 | return write_req; |
---|
2504 | } |
---|
2505 | |
---|
2506 | /** |
---|
2507 | * The swapout worker thread body. |
---|
2508 | * |
---|
2509 | * @param arg A pointer to the worker thread's private data. |
---|
2510 | * @return rtems_task Not used. |
---|
2511 | */ |
---|
2512 | static rtems_task |
---|
2513 | rtems_bdbuf_swapout_worker_task (rtems_task_argument arg) |
---|
2514 | { |
---|
2515 | rtems_bdbuf_swapout_worker* worker = (rtems_bdbuf_swapout_worker*) arg; |
---|
2516 | |
---|
2517 | while (worker->enabled) |
---|
2518 | { |
---|
2519 | rtems_event_set out; |
---|
2520 | rtems_status_code sc; |
---|
2521 | |
---|
2522 | sc = rtems_event_receive (RTEMS_BDBUF_SWAPOUT_SYNC, |
---|
2523 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
2524 | RTEMS_NO_TIMEOUT, |
---|
2525 | &out); |
---|
2526 | |
---|
2527 | if (sc != RTEMS_SUCCESSFUL) |
---|
2528 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
2529 | |
---|
2530 | rtems_bdbuf_swapout_write (&worker->transfer); |
---|
2531 | |
---|
2532 | rtems_bdbuf_lock_cache (); |
---|
2533 | |
---|
2534 | rtems_chain_initialize_empty (&worker->transfer.bds); |
---|
2535 | worker->transfer.dev = -1; |
---|
2536 | |
---|
2537 | rtems_chain_append (&bdbuf_cache.swapout_workers, &worker->link); |
---|
2538 | |
---|
2539 | rtems_bdbuf_unlock_cache (); |
---|
2540 | } |
---|
2541 | |
---|
2542 | free (worker->transfer.write_req); |
---|
2543 | free (worker); |
---|
2544 | |
---|
2545 | rtems_task_delete (RTEMS_SELF); |
---|
2546 | } |
---|
2547 | |
---|
2548 | /** |
---|
2549 | * Open the swapout worker threads. |
---|
2550 | */ |
---|
2551 | static void |
---|
2552 | rtems_bdbuf_swapout_workers_open (void) |
---|
2553 | { |
---|
2554 | rtems_status_code sc; |
---|
2555 | int w; |
---|
2556 | |
---|
2557 | rtems_bdbuf_lock_cache (); |
---|
2558 | |
---|
2559 | for (w = 0; w < rtems_bdbuf_configuration.swapout_workers; w++) |
---|
2560 | { |
---|
2561 | rtems_bdbuf_swapout_worker* worker; |
---|
2562 | |
---|
2563 | worker = malloc (sizeof (rtems_bdbuf_swapout_worker)); |
---|
2564 | if (!worker) |
---|
2565 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM); |
---|
2566 | |
---|
2567 | rtems_chain_append (&bdbuf_cache.swapout_workers, &worker->link); |
---|
2568 | worker->enabled = true; |
---|
2569 | worker->transfer.write_req = rtems_bdbuf_swapout_writereq_alloc (); |
---|
2570 | |
---|
2571 | rtems_chain_initialize_empty (&worker->transfer.bds); |
---|
2572 | worker->transfer.dev = -1; |
---|
2573 | |
---|
2574 | sc = rtems_task_create (rtems_build_name('B', 'D', 'o', 'a' + w), |
---|
2575 | (rtems_bdbuf_configuration.swapout_priority ? |
---|
2576 | rtems_bdbuf_configuration.swapout_priority : |
---|
2577 | RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT), |
---|
2578 | SWAPOUT_TASK_STACK_SIZE, |
---|
2579 | RTEMS_PREEMPT | RTEMS_NO_TIMESLICE | RTEMS_NO_ASR, |
---|
2580 | RTEMS_LOCAL | RTEMS_NO_FLOATING_POINT, |
---|
2581 | &worker->id); |
---|
2582 | if (sc != RTEMS_SUCCESSFUL) |
---|
2583 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_CREATE); |
---|
2584 | |
---|
2585 | sc = rtems_task_start (worker->id, |
---|
2586 | rtems_bdbuf_swapout_worker_task, |
---|
2587 | (rtems_task_argument) worker); |
---|
2588 | if (sc != RTEMS_SUCCESSFUL) |
---|
2589 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_START); |
---|
2590 | } |
---|
2591 | |
---|
2592 | rtems_bdbuf_unlock_cache (); |
---|
2593 | } |
---|
2594 | |
---|
2595 | /** |
---|
2596 | * Close the swapout worker threads. |
---|
2597 | */ |
---|
2598 | static void |
---|
2599 | rtems_bdbuf_swapout_workers_close (void) |
---|
2600 | { |
---|
2601 | rtems_chain_node* node; |
---|
2602 | |
---|
2603 | rtems_bdbuf_lock_cache (); |
---|
2604 | |
---|
2605 | node = rtems_chain_first (&bdbuf_cache.swapout_workers); |
---|
2606 | while (!rtems_chain_is_tail (&bdbuf_cache.swapout_workers, node)) |
---|
2607 | { |
---|
2608 | rtems_bdbuf_swapout_worker* worker = (rtems_bdbuf_swapout_worker*) node; |
---|
2609 | worker->enabled = false; |
---|
2610 | rtems_event_send (worker->id, RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
2611 | node = rtems_chain_next (node); |
---|
2612 | } |
---|
2613 | |
---|
2614 | rtems_bdbuf_unlock_cache (); |
---|
2615 | } |
---|
2616 | |
---|
2617 | /** |
---|
2618 | * Body of task which takes care on flushing modified buffers to the disk. |
---|
2619 | * |
---|
2620 | * @param arg A pointer to the global cache data. Use the global variable and |
---|
2621 | * not this. |
---|
2622 | * @return rtems_task Not used. |
---|
2623 | */ |
---|
2624 | static rtems_task |
---|
2625 | rtems_bdbuf_swapout_task (rtems_task_argument arg) |
---|
2626 | { |
---|
2627 | rtems_bdbuf_swapout_transfer transfer; |
---|
2628 | uint32_t period_in_ticks; |
---|
2629 | const uint32_t period_in_msecs = bdbuf_config.swapout_period;; |
---|
2630 | uint32_t timer_delta; |
---|
2631 | |
---|
2632 | transfer.write_req = rtems_bdbuf_swapout_writereq_alloc (); |
---|
2633 | rtems_chain_initialize_empty (&transfer.bds); |
---|
2634 | transfer.dev = -1; |
---|
2635 | |
---|
2636 | /* |
---|
2637 | * Localise the period. |
---|
2638 | */ |
---|
2639 | period_in_ticks = RTEMS_MICROSECONDS_TO_TICKS (period_in_msecs * 1000); |
---|
2640 | |
---|
2641 | /* |
---|
2642 | * This is temporary. Needs to be changed to use the real time clock. |
---|
2643 | */ |
---|
2644 | timer_delta = period_in_msecs; |
---|
2645 | |
---|
2646 | /* |
---|
2647 | * Create the worker threads. |
---|
2648 | */ |
---|
2649 | rtems_bdbuf_swapout_workers_open (); |
---|
2650 | |
---|
2651 | while (bdbuf_cache.swapout_enabled) |
---|
2652 | { |
---|
2653 | rtems_event_set out; |
---|
2654 | rtems_status_code sc; |
---|
2655 | |
---|
2656 | /* |
---|
2657 | * Only update the timers once in the processing cycle. |
---|
2658 | */ |
---|
2659 | bool update_timers = true; |
---|
2660 | |
---|
2661 | /* |
---|
2662 | * If we write buffers to any disk perform a check again. We only write a |
---|
2663 | * single device at a time and the cache may have more than one device's |
---|
2664 | * buffers modified waiting to be written. |
---|
2665 | */ |
---|
2666 | bool transfered_buffers; |
---|
2667 | |
---|
2668 | do |
---|
2669 | { |
---|
2670 | transfered_buffers = false; |
---|
2671 | |
---|
2672 | /* |
---|
2673 | * Extact all the buffers we find for a specific device. The device is |
---|
2674 | * the first one we find on a modified list. Process the sync queue of |
---|
2675 | * buffers first. |
---|
2676 | */ |
---|
2677 | if (rtems_bdbuf_swapout_processing (timer_delta, |
---|
2678 | update_timers, |
---|
2679 | &transfer)) |
---|
2680 | { |
---|
2681 | transfered_buffers = true; |
---|
2682 | } |
---|
2683 | |
---|
2684 | /* |
---|
2685 | * Only update the timers once. |
---|
2686 | */ |
---|
2687 | update_timers = false; |
---|
2688 | } |
---|
2689 | while (transfered_buffers); |
---|
2690 | |
---|
2691 | sc = rtems_event_receive (RTEMS_BDBUF_SWAPOUT_SYNC, |
---|
2692 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
2693 | period_in_ticks, |
---|
2694 | &out); |
---|
2695 | |
---|
2696 | if ((sc != RTEMS_SUCCESSFUL) && (sc != RTEMS_TIMEOUT)) |
---|
2697 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
2698 | } |
---|
2699 | |
---|
2700 | rtems_bdbuf_swapout_workers_close (); |
---|
2701 | |
---|
2702 | free (transfer.write_req); |
---|
2703 | |
---|
2704 | rtems_task_delete (RTEMS_SELF); |
---|
2705 | } |
---|
2706 | |
---|