1 | /* |
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2 | * devfs.h - DEVFS File System API definition |
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3 | * |
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4 | * Authors Mohamed Lamine Karaoui (2014,2015) |
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5 | * Alain Greiner (2016,2017) |
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6 | * |
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7 | * Copyright (c) 2011,2012 UPMC Sorbonne Universites |
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8 | * |
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9 | * This file is part of ALMOS-MKH. |
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10 | * |
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11 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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12 | * under the terms of the GNU General Public License as published by |
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13 | * the Free Software Foundation; version 2.0 of the License. |
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14 | * |
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15 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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16 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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18 | * General Public License for more details. |
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19 | * |
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20 | * You should have received a copy of the GNU General Public License |
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21 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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22 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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23 | */ |
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24 | |
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25 | #ifndef _DEVFS_H_ |
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26 | #define _DEVFS_H_ |
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27 | |
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28 | ////////////////////////////////////////////////////////////////////////////////////////// |
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29 | // The DEVFS File System contains inodes and dentries associated to all chdev descriptors |
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30 | // availables in the architecture. It is structured as a three levels tree structure : |
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31 | // - The "dev" directory inode is stored in cluster_IO. It is the root of the DEVFS |
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32 | // file system. The parent inode is the "/" VFS root. |
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33 | // - There is one "internal_cxy" directory inode per cluster, that is the parent of |
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34 | // the local children inodes associated to the local, internal chdev descriptors. |
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35 | // The parent dentry is stored in cluster_IO. |
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36 | // - The I/O cluster contains one "external" directory inode, that is the parent of |
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37 | // the remote children inodes associated to the remote external chdev descriptors. |
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38 | // The parent dentry is stored in cluster_IO. |
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39 | // |
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40 | // The DEVFS file system uses the DEVFS context extension to register an extended pointer |
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41 | // on the DEVFS "dev" inode, and and another extended pointer on the "external" inode. |
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42 | // |
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43 | // The DEVFS file system uses the VFS inode extension to store the pointer |
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44 | // on the associated chdev descriptor. |
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45 | ////////////////////////////////////////////////////////////////////////////////////////// |
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46 | |
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47 | /***************************************************************************************** |
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48 | * This structure defines the DEVFS context extension. |
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49 | ****************************************************************************************/ |
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50 | |
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51 | typedef struct devfs_ctx_s |
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52 | { |
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53 | xptr_t dev_inode_xp; /*! extended pointer on DEVFS root inode */ |
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54 | xptr_t external_inode_xp; /*! extended pointer on DEVFS external inode */ |
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55 | } |
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56 | devfs_ctx_t; |
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57 | |
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58 | |
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59 | /***************************************************************************************** |
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60 | * This fuction allocates memory from local cluster for a DEVFS context descriptor. |
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61 | ***************************************************************************************** |
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62 | * @ return a pointer on the created context / return NULL if failure. |
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63 | ****************************************************************************************/ |
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64 | devfs_ctx_t * devfs_ctx_alloc(); |
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65 | |
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66 | /***************************************************************************************** |
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67 | * This function initialises the DEVFS context from arguments values, and link it |
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68 | * to the relevant VFS context in the local cluster. |
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69 | ***************************************************************************************** |
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70 | * @ devfs_ctx : local pointer on DEVFS context. |
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71 | * @ devfs_dev_inode_xp : [out] extended pointer on <dev> inode. |
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72 | * @ devfs_external_inode_xp : [out] extended pointer on <external> inode. |
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73 | ****************************************************************************************/ |
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74 | void devfs_ctx_init( devfs_ctx_t * devfs_ctx, |
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75 | xptr_t devfs_dev_inode_xp, |
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76 | xptr_t devfs_external_inode_xp ); |
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77 | |
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78 | /***************************************************************************************** |
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79 | * This function releases memory dynamically allocated for the DEVFS context. |
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80 | ***************************************************************************************** |
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81 | * @ devfs_ctx : local pointer on DEVFS context. |
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82 | ****************************************************************************************/ |
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83 | void devfs_ctx_destroy( devfs_ctx_t * devfs_ctx ); |
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84 | |
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85 | /***************************************************************************************** |
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86 | * This function start to create the DEVFS subtree. |
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87 | * This function should be called once in the cluster containing the VFS parent inode. |
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88 | * More precisely, it creates in cluster IO the "dev" and "external" DEVFS directories. |
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89 | * For each one, it creates the inode and link the associated dentry to parent inode. |
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90 | * The DEVFS root inode is linked to the VFS parent inode identified by <parent_inode_xp>. |
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91 | ***************************************************************************************** |
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92 | * @ parent_inode_xp : extended pointer on the parent VFS inode. |
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93 | * @ devfs_dev_inode_xp : [out] extended pointer on created <dev> inode. |
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94 | * @ devfs_external_inode_xp : [out] extended pointer on created <external> inode. |
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95 | ****************************************************************************************/ |
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96 | void devfs_global_init( xptr_t parent_inode_xp, |
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97 | xptr_t * devfs_dev_inode_xp, |
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98 | xptr_t * devfs_external_inode_xp ); |
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99 | |
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100 | /***************************************************************************************** |
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101 | * This function completes the initialisation of the DEVFS subtree. |
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102 | * It should be called once in each cluster. |
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103 | * 1. In each cluster (i), it creates the "internal" directory, |
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104 | * linked to the DEVFS "dev" parent directory. |
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105 | * 2. In each cluster (i), it creates - for each external chdev in cluster (i) - |
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106 | * a pseudo-file, linked to the DEVFS "external" parent directory. |
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107 | * 3. In each cluster (i), it creates - for each internal chdev in cluster (i) - |
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108 | * a pseudo-file, linked to the DEVFS "internal" parent directory. |
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109 | ***************************************************************************************** |
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110 | * @ devfs_dev_inode_xp : extended pointer on DEVFS root inode. |
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111 | * @ devfs_external_inode_xp : extended pointer on DEVFS external inode. |
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112 | * @ devfs_internal_inode_xp : [out] extended pointer on created <internal> inode. |
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113 | ****************************************************************************************/ |
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114 | void devfs_local_init( xptr_t devfs_dev_inode_xp, |
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115 | xptr_t devfs_external_inode_xp, |
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116 | xptr_t * devfs_internal_inode_xp ); |
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117 | |
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118 | #endif /* _DEVFS_H_ */ |
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