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| 2 | pj | 1 | /* |
| 2 | * Project: HARTIK (HA-rd R-eal TI-me K-ernel) |
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| 3 | * |
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| 4 | * Coordinators: Giorgio Buttazzo <giorgio@sssup.it> |
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| 5 | * Gerardo Lamastra <gerardo@sssup.it> |
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| 6 | * |
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| 7 | * Authors : Massimiliano Giorgi <massy@hartik.sssup.it> |
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| 8 | * (see authors.txt for full list of hartik's authors) |
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| 9 | * |
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| 10 | * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy) |
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| 11 | * |
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| 12 | * http://www.sssup.it |
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| 13 | * http://retis.sssup.it |
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| 14 | * http://hartik.sssup.it |
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| 15 | */ |
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| 16 | |||
| 17 | /* |
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| 18 | * Copyright (C) 2000 Massimiliano Giorgi |
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| 19 | * |
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| 20 | * This program is free software; you can redistribute it and/or modify |
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| 21 | * it under the terms of the GNU General Public License as published by |
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| 22 | * the Free Software Foundation; either version 2 of the License, or |
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| 23 | * (at your option) any later version. |
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| 24 | * |
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| 25 | * This program is distributed in the hope that it will be useful, |
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| 26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 28 | * GNU General Public License for more details. |
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| 29 | * |
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| 30 | * You should have received a copy of the GNU General Public License |
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| 31 | * along with this program; if not, write to the Free Software |
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| 32 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 33 | * |
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| 34 | */ |
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| 35 | |||
| 36 | /* |
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| 37 | * CVS : $Id: dcache.h,v 1.1.1.1 2002-03-29 14:12:50 pj Exp $ |
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| 38 | * |
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| 39 | * File: $File$ |
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| 40 | * Revision: $Revision: 1.1.1.1 $ |
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| 41 | * Last update: $Date: 2002-03-29 14:12:50 $ |
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| 42 | */ |
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| 43 | |||
| 44 | /*** |
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| 45 | This is the caching module: all the I/O requestes of filesystems MUST pass throught this to |
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| 46 | read/write on disks. |
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| 47 | ***/ |
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| 48 | |||
| 49 | #ifndef __DCACHE_H__ |
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| 50 | #define __DCACHE_H__ |
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| 51 | |||
| 52 | #include <fs/types.h> |
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| 53 | #include <fs/magic.h> |
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| 54 | #include <fs/bdev.h> |
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| 55 | |||
| 56 | #include "semaph.h" |
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| 57 | #include "rwlock.h" |
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| 58 | |||
| 59 | #define MAXSECTORSIZE 512 |
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| 60 | |||
| 61 | typedef struct TAGdcache { |
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| 62 | |||
| 63 | DECLARE_MAGIC(magic); |
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| 64 | |||
| 65 | /*+ index of previous cache entry (if used) +*/ |
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| 66 | int prev; |
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| 67 | /*+ index of next cache entry +*/ |
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| 68 | int next; |
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| 69 | /*+ hash value +*/ |
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| 70 | int hash; |
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| 71 | |||
| 72 | |||
| 73 | /*+ device of this entry +*/ |
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| 74 | __dev_t device; |
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| 75 | /*+ logical sector of this entry +*/ |
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| 76 | __blkcnt_t lsector; |
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| 77 | /*+ sector buffer +*/ |
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| 78 | __uint8_t buffer[MAXSECTORSIZE]; |
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| 79 | |||
| 80 | |||
| 81 | |||
| 82 | /*+ how many threads are using this entry? +*/ |
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| 83 | /* -1: unused and free 0: unused >0: used by 'used' thread */ |
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| 84 | int used; |
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| 85 | /*+ system tyme of last release +*/ |
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| 86 | __time_t time; |
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| 87 | |||
| 88 | |||
| 89 | /*+ number of threads waiting for 'ready' field +*/ |
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| 90 | int numblocked; |
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| 91 | /*+ all 'numblocked' threads wait on this semaphore +*/ |
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| 92 | __fs_sem_t sync; |
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| 93 | /*+ for error syncronization [see __purge_dcache()] +*/ |
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| 94 | __fs_sem_t esync; |
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| 95 | |||
| 96 | |||
| 97 | /*+ reading/writing mutex object [see rwlock.c module] +*/ |
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| 98 | __rwlock_t rwlock; |
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| 99 | |||
| 100 | |||
| 101 | /* flags */ |
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| 102 | |||
| 103 | /*+ the buffer has been modified +*/ |
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| 104 | __uint32_t dirty:1; |
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| 105 | /*+ the buffer is ready +*/ |
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| 106 | __uint32_t ready:1; |
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| 107 | /*+ request for error syncronization [see __purge_dcache()] +*/ |
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| 108 | __uint32_t esyncreq:1; |
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| 109 | /*+ if set a write throught cache policy for this entry is not honoured +*/ |
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| 110 | __uint32_t skipwt:1; |
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| 111 | |||
| 112 | } dcache_t; |
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| 113 | |||
| 114 | int dcache_init(void); |
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| 115 | int dcache_end(int flag); |
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| 116 | |||
| 117 | dcache_t *dcache_lock(__dev_t dev, __blkcnt_t lsector); |
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| 118 | void dcache_unlock(dcache_t *); |
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| 119 | dcache_t *dcache_acquire(__dev_t dev, __blkcnt_t lsector); |
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| 120 | void dcache_release(dcache_t *); |
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| 121 | |||
| 122 | void dcache_dirty(dcache_t *d); |
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| 123 | |||
| 124 | static __inline__ void dcache_skipwt(dcache_t *d) |
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| 125 | { |
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| 126 | d->skipwt=1; |
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| 127 | } |
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| 128 | |||
| 129 | int dcache_flush(void); |
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| 130 | int dcache_purgedevice(__dev_t device, int cont); |
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| 131 | |||
| 132 | /* -- */ |
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| 133 | |||
| 134 | #define DCACHE_OK BDEV_OK |
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| 135 | #define DCACHE_FAIL BDEV_FAIL |
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| 136 | #define DCACHE_ERR BDEV_ERROR |
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| 137 | |||
| 138 | extern __inline__ int dcache_lockdevice(__dev_t device) |
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| 139 | { |
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| 140 | return bdev_trylock(device); |
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| 141 | } |
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| 142 | |||
| 143 | extern __inline__ int dcache_unlockdevice(__dev_t device) |
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| 144 | { |
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| 145 | return bdev_tryunlock(device); |
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| 146 | } |
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| 147 | |||
| 148 | |||
| 149 | #endif |
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| 150 | |||
| 151 |