1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup rtems_disk |
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5 | * |
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6 | * @brief Block device disk management implementation. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
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11 | * Author: Victor V. Vengerov <vvv@oktet.ru> |
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12 | * |
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13 | * Copyright (c) 2009 embedded brains GmbH. |
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14 | * |
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15 | * @(#) $Id$ |
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16 | */ |
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17 | |
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18 | #if HAVE_CONFIG_H |
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19 | #include "config.h" |
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20 | #endif |
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21 | |
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22 | #include <stdlib.h> |
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23 | #include <unistd.h> |
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24 | #include <string.h> |
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25 | |
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26 | #include <rtems.h> |
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27 | #include <rtems/libio.h> |
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28 | #include <rtems/diskdevs.h> |
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29 | #include <rtems/blkdev.h> |
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30 | #include <rtems/bdbuf.h> |
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31 | |
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32 | #define DISKTAB_INITIAL_SIZE 8 |
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33 | |
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34 | /* Table of disk devices having the same major number */ |
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35 | typedef struct rtems_disk_device_table { |
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36 | rtems_disk_device **minor; /* minor-indexed disk device table */ |
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37 | rtems_device_minor_number size; /* Number of entries in the table */ |
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38 | } rtems_disk_device_table; |
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39 | |
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40 | /* Pointer to [major].minor[minor] indexed array of disk devices */ |
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41 | static rtems_disk_device_table *disktab; |
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42 | |
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43 | /* Number of allocated entries in disktab table */ |
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44 | static rtems_device_major_number disktab_size; |
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45 | |
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46 | /* Mutual exclusion semaphore for disk devices table */ |
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47 | static rtems_id diskdevs_mutex; |
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48 | |
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49 | /* diskdevs data structures protection flag. |
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50 | * Normally, only table lookup operations performed. It is quite fast, so |
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51 | * it is possible to done lookups when interrupts are disabled, avoiding |
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52 | * obtaining the semaphore. This flags sets immediately after entering in |
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53 | * mutex-protected section and cleared before leaving this section in |
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54 | * "big" primitives like add/delete new device etc. Lookup function first |
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55 | * disable interrupts and check this flag. If it is set, lookup function |
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56 | * will be blocked on semaphore and lookup operation will be performed in |
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57 | * semaphore-protected code. If it is not set (very-very frequent case), |
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58 | * we can do lookup safely, enable interrupts and return result. |
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59 | */ |
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60 | static volatile bool diskdevs_protected; |
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61 | |
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62 | static rtems_status_code |
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63 | disk_lock(void) |
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64 | { |
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65 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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66 | |
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67 | sc = rtems_semaphore_obtain(diskdevs_mutex, RTEMS_WAIT, RTEMS_NO_TIMEOUT); |
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68 | if (sc == RTEMS_SUCCESSFUL) { |
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69 | diskdevs_protected = true; |
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70 | |
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71 | return RTEMS_SUCCESSFUL; |
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72 | } else { |
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73 | return RTEMS_NOT_CONFIGURED; |
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74 | } |
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75 | } |
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76 | |
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77 | static void |
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78 | disk_unlock(void) |
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79 | { |
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80 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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81 | |
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82 | diskdevs_protected = false; |
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83 | |
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84 | sc = rtems_semaphore_release(diskdevs_mutex); |
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85 | if (sc != RTEMS_SUCCESSFUL) { |
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86 | /* FIXME: Error number */ |
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87 | rtems_fatal_error_occurred(0xdeadbeef); |
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88 | } |
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89 | } |
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90 | |
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91 | static rtems_disk_device * |
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92 | get_disk_entry(dev_t dev) |
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93 | { |
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94 | rtems_device_major_number major = 0; |
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95 | rtems_device_minor_number minor = 0; |
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96 | |
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97 | rtems_filesystem_split_dev_t(dev, major, minor); |
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98 | |
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99 | if (major < disktab_size && disktab != NULL) { |
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100 | rtems_disk_device_table *dtab = disktab + major; |
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101 | |
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102 | if (minor < dtab->size && dtab->minor != NULL) { |
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103 | rtems_disk_device *dd = dtab->minor [minor]; |
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104 | |
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105 | if (dd != NULL && !dd->deleted) { |
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106 | ++dd->uses; |
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107 | |
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108 | return dd; |
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109 | } |
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110 | } |
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111 | } |
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112 | |
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113 | return NULL; |
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114 | } |
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115 | |
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116 | static rtems_disk_device ** |
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117 | create_disk_table_entry(dev_t dev) |
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118 | { |
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119 | rtems_device_major_number major = 0; |
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120 | rtems_device_minor_number minor = 0; |
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121 | |
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122 | rtems_filesystem_split_dev_t(dev, major, minor); |
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123 | |
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124 | if (major >= disktab_size) { |
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125 | rtems_disk_device_table *table = disktab; |
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126 | rtems_device_major_number old_size = disktab_size; |
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127 | rtems_device_major_number new_size = 2 * old_size; |
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128 | |
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129 | if (major >= new_size) { |
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130 | new_size = major + 1; |
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131 | } |
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132 | |
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133 | table = realloc(table, new_size * sizeof(*table)); |
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134 | if (table == NULL) { |
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135 | return NULL; |
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136 | } |
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137 | |
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138 | memset(table + old_size, 0, (new_size - old_size) * sizeof(*table)); |
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139 | disktab = table; |
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140 | disktab_size = new_size; |
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141 | } |
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142 | |
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143 | if (disktab [major].minor == NULL || minor >= disktab[major].size) { |
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144 | rtems_disk_device **table = disktab [major].minor; |
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145 | rtems_device_minor_number old_size = disktab [major].size; |
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146 | rtems_device_minor_number new_size = 0; |
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147 | |
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148 | if (old_size == 0) { |
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149 | new_size = DISKTAB_INITIAL_SIZE; |
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150 | } else { |
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151 | new_size = 2 * old_size; |
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152 | } |
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153 | if (minor >= new_size) { |
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154 | new_size = minor + 1; |
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155 | } |
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156 | |
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157 | table = realloc(table, new_size * sizeof(*table)); |
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158 | if (table == NULL) { |
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159 | return NULL; |
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160 | } |
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161 | |
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162 | memset(table + old_size, 0, (new_size - old_size) * sizeof(*table)); |
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163 | disktab [major].minor = table; |
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164 | disktab [major].size = new_size; |
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165 | } |
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166 | |
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167 | return disktab [major].minor + minor; |
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168 | } |
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169 | |
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170 | static rtems_status_code |
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171 | create_disk(dev_t dev, const char *name, rtems_disk_device **dd_ptr) |
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172 | { |
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173 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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174 | rtems_disk_device **dd_entry = create_disk_table_entry(dev); |
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175 | rtems_disk_device *dd = NULL; |
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176 | char *alloc_name = NULL; |
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177 | |
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178 | if (dd_entry == NULL) { |
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179 | return RTEMS_NO_MEMORY; |
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180 | } |
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181 | |
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182 | if (*dd_entry != NULL) { |
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183 | return RTEMS_RESOURCE_IN_USE; |
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184 | } |
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185 | |
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186 | dd = malloc(sizeof(*dd)); |
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187 | if (dd == NULL) { |
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188 | return RTEMS_NO_MEMORY; |
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189 | } |
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190 | |
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191 | if (name != NULL) { |
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192 | alloc_name = strdup(name); |
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193 | |
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194 | if (alloc_name == NULL) { |
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195 | free(dd); |
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196 | |
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197 | return RTEMS_NO_MEMORY; |
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198 | } |
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199 | } |
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200 | |
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201 | if (name != NULL) { |
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202 | rtems_device_major_number major = 0; |
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203 | rtems_device_minor_number minor = 0; |
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204 | |
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205 | rtems_filesystem_split_dev_t(dev, major, minor); |
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206 | |
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207 | sc = rtems_io_register_name(name, major, minor); |
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208 | if (sc != RTEMS_SUCCESSFUL) { |
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209 | free(alloc_name); |
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210 | free(dd); |
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211 | |
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212 | return RTEMS_UNSATISFIED; |
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213 | } |
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214 | } |
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215 | |
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216 | dd->dev = dev; |
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217 | dd->name = alloc_name; |
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218 | dd->uses = 0; |
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219 | dd->deleted = false; |
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220 | |
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221 | *dd_entry = dd; |
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222 | *dd_ptr = dd; |
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223 | |
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224 | return RTEMS_SUCCESSFUL; |
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225 | } |
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226 | |
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227 | rtems_status_code rtems_disk_create_phys( |
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228 | dev_t dev, |
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229 | uint32_t block_size, |
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230 | rtems_blkdev_bnum block_count, |
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231 | rtems_block_device_ioctl handler, |
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232 | void *driver_data, |
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233 | const char *name |
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234 | ) |
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235 | { |
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236 | rtems_disk_device *dd = NULL; |
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237 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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238 | |
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239 | if (handler == NULL) { |
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240 | return RTEMS_INVALID_ADDRESS; |
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241 | } |
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242 | |
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243 | if (block_size == 0) { |
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244 | return RTEMS_INVALID_NUMBER; |
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245 | } |
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246 | |
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247 | sc = disk_lock(); |
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248 | if (sc != RTEMS_SUCCESSFUL) { |
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249 | return sc; |
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250 | } |
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251 | |
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252 | sc = create_disk(dev, name, &dd); |
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253 | if (sc != RTEMS_SUCCESSFUL) { |
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254 | disk_unlock(); |
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255 | |
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256 | return sc; |
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257 | } |
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258 | |
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259 | dd->phys_dev = dd; |
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260 | dd->start = 0; |
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261 | dd->size = block_count; |
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262 | dd->block_size = dd->media_block_size = block_size; |
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263 | dd->ioctl = handler; |
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264 | dd->driver_data = driver_data; |
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265 | |
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266 | if ((*handler)(dd, RTEMS_BLKDEV_CAPABILITIES, &dd->capabilities) < 0) { |
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267 | dd->capabilities = 0; |
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268 | } |
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269 | |
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270 | disk_unlock(); |
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271 | |
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272 | return RTEMS_SUCCESSFUL; |
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273 | } |
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274 | |
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275 | static bool |
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276 | is_physical_disk(const rtems_disk_device *dd) |
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277 | { |
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278 | return dd->phys_dev == dd; |
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279 | } |
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280 | |
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281 | rtems_status_code rtems_disk_create_log( |
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282 | dev_t dev, |
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283 | dev_t phys, |
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284 | rtems_blkdev_bnum begin_block, |
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285 | rtems_blkdev_bnum block_count, |
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286 | const char *name |
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287 | ) |
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288 | { |
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289 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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290 | rtems_disk_device *physical_disk = NULL; |
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291 | rtems_disk_device *dd = NULL; |
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292 | rtems_blkdev_bnum end_block = begin_block + block_count; |
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293 | |
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294 | sc = disk_lock(); |
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295 | if (sc != RTEMS_SUCCESSFUL) { |
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296 | return sc; |
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297 | } |
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298 | |
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299 | physical_disk = get_disk_entry(phys); |
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300 | if (physical_disk == NULL || !is_physical_disk(physical_disk)) { |
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301 | if (physical_disk != NULL) { |
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302 | --physical_disk->uses; |
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303 | } |
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304 | disk_unlock(); |
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305 | |
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306 | return RTEMS_INVALID_ID; |
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307 | } |
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308 | |
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309 | if ( |
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310 | begin_block >= physical_disk->size |
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311 | || end_block <= begin_block |
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312 | || end_block > physical_disk->size |
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313 | ) { |
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314 | --physical_disk->uses; |
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315 | disk_unlock(); |
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316 | |
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317 | return RTEMS_INVALID_NUMBER; |
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318 | } |
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319 | |
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320 | sc = create_disk(dev, name, &dd); |
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321 | if (sc != RTEMS_SUCCESSFUL) { |
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322 | --physical_disk->uses; |
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323 | disk_unlock(); |
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324 | |
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325 | return sc; |
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326 | } |
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327 | |
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328 | dd->phys_dev = physical_disk; |
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329 | dd->start = begin_block; |
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330 | dd->size = block_count; |
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331 | dd->block_size = dd->media_block_size = physical_disk->block_size; |
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332 | dd->ioctl = physical_disk->ioctl; |
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333 | dd->driver_data = physical_disk->driver_data; |
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334 | |
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335 | disk_unlock(); |
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336 | |
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337 | return RTEMS_SUCCESSFUL; |
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338 | } |
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339 | |
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340 | static void |
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341 | free_disk_device(rtems_disk_device *dd) |
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342 | { |
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343 | if (is_physical_disk(dd)) { |
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344 | (*dd->ioctl)(dd, RTEMS_BLKIO_DELETED, NULL); |
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345 | } |
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346 | if (dd->name != NULL) { |
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347 | unlink(dd->name); |
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348 | free(dd->name); |
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349 | } |
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350 | free(dd); |
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351 | } |
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352 | |
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353 | static void |
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354 | rtems_disk_cleanup(rtems_disk_device *disk_to_remove) |
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355 | { |
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356 | rtems_disk_device *const physical_disk = disk_to_remove->phys_dev; |
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357 | rtems_device_major_number major = 0; |
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358 | rtems_device_minor_number minor = 0; |
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359 | |
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360 | if (physical_disk->deleted) { |
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361 | dev_t dev = physical_disk->dev; |
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362 | unsigned deleted_count = 0; |
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363 | |
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364 | for (major = 0; major < disktab_size; ++major) { |
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365 | rtems_disk_device_table *dtab = disktab + major; |
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366 | |
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367 | for (minor = 0; minor < dtab->size; ++minor) { |
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368 | rtems_disk_device *dd = dtab->minor [minor]; |
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369 | |
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370 | if (dd != NULL && dd->phys_dev->dev == dev && dd != physical_disk) { |
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371 | if (dd->uses == 0) { |
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372 | ++deleted_count; |
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373 | dtab->minor [minor] = NULL; |
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374 | free_disk_device(dd); |
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375 | } else { |
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376 | dd->deleted = true; |
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377 | } |
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378 | } |
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379 | } |
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380 | } |
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381 | |
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382 | physical_disk->uses -= deleted_count; |
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383 | if (physical_disk->uses == 0) { |
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384 | rtems_filesystem_split_dev_t(physical_disk->dev, major, minor); |
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385 | disktab [major].minor [minor] = NULL; |
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386 | free_disk_device(physical_disk); |
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387 | } |
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388 | } else { |
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389 | if (disk_to_remove->uses == 0) { |
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390 | --physical_disk->uses; |
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391 | rtems_filesystem_split_dev_t(disk_to_remove->dev, major, minor); |
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392 | disktab [major].minor [minor] = NULL; |
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393 | free_disk_device(disk_to_remove); |
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394 | } |
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395 | } |
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396 | } |
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397 | |
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398 | rtems_status_code |
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399 | rtems_disk_delete(dev_t dev) |
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400 | { |
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401 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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402 | rtems_disk_device *dd = NULL; |
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403 | |
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404 | sc = disk_lock(); |
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405 | if (sc != RTEMS_SUCCESSFUL) { |
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406 | return sc; |
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407 | } |
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408 | |
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409 | dd = get_disk_entry(dev); |
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410 | if (dd == NULL) { |
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411 | disk_unlock(); |
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412 | |
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413 | return RTEMS_INVALID_ID; |
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414 | } |
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415 | |
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416 | --dd->uses; |
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417 | dd->deleted = true; |
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418 | rtems_disk_cleanup(dd); |
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419 | |
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420 | disk_unlock(); |
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421 | |
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422 | return RTEMS_SUCCESSFUL; |
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423 | } |
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424 | |
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425 | rtems_disk_device * |
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426 | rtems_disk_obtain(dev_t dev) |
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427 | { |
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428 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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429 | rtems_disk_device *dd = NULL; |
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430 | rtems_interrupt_level level; |
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431 | |
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432 | rtems_interrupt_disable(level); |
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433 | if (!diskdevs_protected) { |
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434 | /* Frequent and quickest case */ |
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435 | dd = get_disk_entry(dev); |
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436 | rtems_interrupt_enable(level); |
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437 | } else { |
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438 | rtems_interrupt_enable(level); |
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439 | |
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440 | sc = disk_lock(); |
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441 | if (sc == RTEMS_SUCCESSFUL) { |
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442 | dd = get_disk_entry(dev); |
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443 | disk_unlock(); |
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444 | } |
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445 | } |
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446 | |
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447 | return dd; |
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448 | } |
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449 | |
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450 | rtems_status_code |
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451 | rtems_disk_release(rtems_disk_device *dd) |
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452 | { |
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453 | rtems_interrupt_level level; |
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454 | dev_t dev = dd->dev; |
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455 | unsigned uses = 0; |
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456 | bool deleted = false; |
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457 | |
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458 | rtems_interrupt_disable(level); |
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459 | uses = --dd->uses; |
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460 | deleted = dd->deleted; |
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461 | rtems_interrupt_enable(level); |
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462 | |
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463 | if (uses == 0 && deleted) { |
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464 | rtems_disk_delete(dev); |
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465 | } |
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466 | |
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467 | return RTEMS_SUCCESSFUL; |
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468 | } |
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469 | |
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470 | rtems_disk_device * |
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471 | rtems_disk_next(dev_t dev) |
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472 | { |
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473 | rtems_device_major_number major; |
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474 | rtems_device_minor_number minor; |
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475 | rtems_disk_device_table *dtab; |
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476 | |
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477 | dev++; |
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478 | rtems_filesystem_split_dev_t (dev, major, minor); |
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479 | |
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480 | if (major >= disktab_size) |
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481 | return NULL; |
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482 | |
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483 | dtab = disktab + major; |
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484 | while (true) |
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485 | { |
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486 | if ((dtab == NULL) || (minor > dtab->size)) |
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487 | { |
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488 | major++; minor = 0; |
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489 | if (major >= disktab_size) |
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490 | return NULL; |
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491 | dtab = disktab + major; |
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492 | } |
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493 | else if (dtab->minor[minor] == NULL) |
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494 | { |
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495 | minor++; |
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496 | } |
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497 | else |
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498 | return dtab->minor[minor]; |
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499 | } |
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500 | } |
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501 | |
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502 | rtems_status_code |
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503 | rtems_disk_io_initialize(void) |
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504 | { |
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505 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
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506 | rtems_device_major_number size = DISKTAB_INITIAL_SIZE; |
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507 | |
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508 | if (disktab_size > 0) { |
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509 | return RTEMS_SUCCESSFUL; |
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510 | } |
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511 | |
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512 | disktab = calloc(size, sizeof(rtems_disk_device_table)); |
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513 | if (disktab == NULL) { |
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514 | return RTEMS_NO_MEMORY; |
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515 | } |
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516 | |
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517 | diskdevs_protected = false; |
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518 | sc = rtems_semaphore_create( |
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519 | rtems_build_name('D', 'D', 'E', 'V'), |
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520 | 1, |
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521 | RTEMS_FIFO | RTEMS_BINARY_SEMAPHORE | RTEMS_NO_INHERIT_PRIORITY |
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522 | | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL, |
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523 | 0, |
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524 | &diskdevs_mutex |
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525 | ); |
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526 | if (sc != RTEMS_SUCCESSFUL) { |
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527 | free(disktab); |
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528 | |
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529 | return RTEMS_NO_MEMORY; |
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530 | } |
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531 | |
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532 | sc = rtems_bdbuf_init(); |
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533 | if (sc != RTEMS_SUCCESSFUL) { |
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534 | rtems_semaphore_delete(diskdevs_mutex); |
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535 | free(disktab); |
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536 | |
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537 | return RTEMS_UNSATISFIED; |
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538 | } |
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539 | |
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540 | disktab_size = size; |
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541 | |
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542 | return RTEMS_SUCCESSFUL; |
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543 | } |
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544 | |
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545 | rtems_status_code |
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546 | rtems_disk_io_done(void) |
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547 | { |
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548 | rtems_device_major_number major = 0; |
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549 | rtems_device_minor_number minor = 0; |
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550 | |
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551 | for (major = 0; major < disktab_size; ++major) { |
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552 | rtems_disk_device_table *dtab = disktab + major; |
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553 | |
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554 | for (minor = 0; minor < dtab->size; ++minor) { |
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555 | rtems_disk_device *dd = dtab->minor [minor]; |
---|
556 | |
---|
557 | if (dd != NULL) { |
---|
558 | free_disk_device(dd); |
---|
559 | } |
---|
560 | } |
---|
561 | free(dtab->minor); |
---|
562 | } |
---|
563 | free(disktab); |
---|
564 | |
---|
565 | rtems_semaphore_delete(diskdevs_mutex); |
---|
566 | |
---|
567 | diskdevs_mutex = RTEMS_ID_NONE; |
---|
568 | disktab = NULL; |
---|
569 | disktab_size = 0; |
---|
570 | |
---|
571 | return RTEMS_SUCCESSFUL; |
---|
572 | } |
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