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3521 jermar 1
/*
2
 * Copyright (c) 2008 Jakub Jermar
3
 * Copyright (c) 2008 Martin Decky
4
 * All rights reserved.
5
 *
6
 * Redistribution and use in source and binary forms, with or without
7
 * modification, are permitted provided that the following conditions
8
 * are met:
9
 *
10
 * - Redistributions of source code must retain the above copyright
11
 *   notice, this list of conditions and the following disclaimer.
12
 * - Redistributions in binary form must reproduce the above copyright
13
 *   notice, this list of conditions and the following disclaimer in the
14
 *   documentation and/or other materials provided with the distribution.
15
 * - The name of the author may not be used to endorse or promote products
16
 *   derived from this software without specific prior written permission.
17
 *
18
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
 */
29
 
30
/** @addtogroup libblock
31
 * @{
32
 */
33
/**
34
 * @file
35
 * @brief
36
 */
37
 
38
#include "libblock.h" 
39
#include "../../srv/vfs/vfs.h"
40
#include "../../srv/rd/rd.h"
3530 jermar 41
#include <ipc/devmap.h>
42
#include <ipc/services.h>
3521 jermar 43
#include <errno.h>
3530 jermar 44
#include <sys/mman.h>
3521 jermar 45
#include <async.h>
46
#include <ipc/ipc.h>
47
#include <as.h>
48
#include <assert.h>
3531 jermar 49
#include <futex.h>
50
#include <libadt/list.h>
3561 svoboda 51
#include <libadt/hash_table.h>
3521 jermar 52
 
3531 jermar 53
/** Lock protecting the device connection list */
54
static futex_t dcl_lock = FUTEX_INITIALIZER;
55
/** Device connection list head. */
56
static LIST_INITIALIZE(dcl_head);
3530 jermar 57
 
3561 svoboda 58
#define CACHE_BUCKETS_LOG2      10
59
#define CACHE_BUCKETS           (1 << CACHE_BUCKETS_LOG2)
60
 
3531 jermar 61
typedef struct {
3561 svoboda 62
    futex_t lock;
63
    size_t block_size;      /**< Block size. */
64
    unsigned block_count;       /**< Total number of blocks. */
65
    hash_table_t block_hash;
66
    link_t free_head;
67
} cache_t;
68
 
69
typedef struct {
3531 jermar 70
    link_t link;
71
    int dev_handle;
72
    int dev_phone;
73
    void *com_area;
74
    size_t com_size;
75
    void *bb_buf;
76
    off_t bb_off;
77
    size_t bb_size;
3561 svoboda 78
    cache_t *cache;
3531 jermar 79
} devcon_t;
80
 
81
static devcon_t *devcon_search(dev_handle_t dev_handle)
82
{
83
    link_t *cur;
84
 
85
    futex_down(&dcl_lock);
86
    for (cur = dcl_head.next; cur != &dcl_head; cur = cur->next) {
87
        devcon_t *devcon = list_get_instance(cur, devcon_t, link);
88
        if (devcon->dev_handle == dev_handle) {
89
            futex_up(&dcl_lock);
90
            return devcon;
91
        }
92
    }
93
    futex_up(&dcl_lock);
94
    return NULL;
95
}
96
 
97
static int devcon_add(dev_handle_t dev_handle, int dev_phone, void *com_area,
3561 svoboda 98
   size_t com_size)
3531 jermar 99
{
100
    link_t *cur;
101
    devcon_t *devcon;
102
 
103
    devcon = malloc(sizeof(devcon_t));
104
    if (!devcon)
105
        return ENOMEM;
106
 
107
    link_initialize(&devcon->link);
108
    devcon->dev_handle = dev_handle;
109
    devcon->dev_phone = dev_phone;
110
    devcon->com_area = com_area;
111
    devcon->com_size = com_size;
3561 svoboda 112
    devcon->bb_buf = NULL;
113
    devcon->bb_off = 0;
114
    devcon->bb_size = 0;
115
    devcon->cache = NULL;
3531 jermar 116
 
117
    futex_down(&dcl_lock);
118
    for (cur = dcl_head.next; cur != &dcl_head; cur = cur->next) {
119
        devcon_t *d = list_get_instance(cur, devcon_t, link);
120
        if (d->dev_handle == dev_handle) {
121
            futex_up(&dcl_lock);
122
            free(devcon);
123
            return EEXIST;
124
        }
125
    }
126
    list_append(&devcon->link, &dcl_head);
127
    futex_up(&dcl_lock);
128
    return EOK;
129
}
130
 
131
static void devcon_remove(devcon_t *devcon)
132
{
133
    futex_down(&dcl_lock);
134
    list_remove(&devcon->link);
135
    futex_up(&dcl_lock);
136
}
137
 
3561 svoboda 138
int block_init(dev_handle_t dev_handle, size_t com_size)
3530 jermar 139
{
140
    int rc;
3531 jermar 141
    int dev_phone;
142
    void *com_area;
143
 
144
    com_area = mmap(NULL, com_size, PROTO_READ | PROTO_WRITE,
3530 jermar 145
        MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
3531 jermar 146
    if (!com_area) {
3530 jermar 147
        return ENOMEM;
148
    }
149
    dev_phone = ipc_connect_me_to(PHONE_NS, SERVICE_DEVMAP,
150
        DEVMAP_CONNECT_TO_DEVICE, dev_handle);
151
 
152
    if (dev_phone < 0) {
3531 jermar 153
        munmap(com_area, com_size);
3530 jermar 154
        return dev_phone;
155
    }
156
 
3531 jermar 157
    rc = ipc_share_out_start(dev_phone, com_area,
3530 jermar 158
        AS_AREA_READ | AS_AREA_WRITE);
159
    if (rc != EOK) {
3531 jermar 160
            munmap(com_area, com_size);
3530 jermar 161
        ipc_hangup(dev_phone);
162
        return rc;
163
    }
3531 jermar 164
 
3561 svoboda 165
    rc = devcon_add(dev_handle, dev_phone, com_area, com_size);
3531 jermar 166
    if (rc != EOK) {
167
        munmap(com_area, com_size);
168
        ipc_hangup(dev_phone);
169
        return rc;
170
    }
171
 
3530 jermar 172
    return EOK;
173
}
174
 
175
void block_fini(dev_handle_t dev_handle)
176
{
3531 jermar 177
    devcon_t *devcon = devcon_search(dev_handle);
178
    assert(devcon);
179
 
180
    devcon_remove(devcon);
181
 
3561 svoboda 182
    if (devcon->bb_buf)
183
        free(devcon->bb_buf);
184
 
185
    if (devcon->cache) {
186
        hash_table_destroy(&devcon->cache->block_hash);
187
        free(devcon->cache);
188
    }
189
 
3531 jermar 190
    munmap(devcon->com_area, devcon->com_size);
191
    ipc_hangup(devcon->dev_phone);
192
 
193
    free(devcon);  
3530 jermar 194
}
195
 
3561 svoboda 196
int block_bb_read(dev_handle_t dev_handle, off_t off, size_t size)
197
{
198
    void *bb_buf;
199
    int rc;
200
 
201
    devcon_t *devcon = devcon_search(dev_handle);
202
    if (!devcon)
203
        return ENOENT;
204
    if (devcon->bb_buf)
205
        return EEXIST;
206
    bb_buf = malloc(size);
207
    if (!bb_buf)
208
        return ENOMEM;
209
 
210
    off_t bufpos = 0;
211
    size_t buflen = 0;
212
    rc = block_read(dev_handle, &bufpos, &buflen, &off,
213
        bb_buf, size, size);
214
    if (rc != EOK) {
215
            free(bb_buf);
216
        return rc;
217
    }
218
    devcon->bb_buf = bb_buf;
219
    devcon->bb_off = off;
220
    devcon->bb_size = size;
221
 
222
    return EOK;
223
}
224
 
3530 jermar 225
void *block_bb_get(dev_handle_t dev_handle)
226
{
3531 jermar 227
    devcon_t *devcon = devcon_search(dev_handle);
228
    assert(devcon);
229
    return devcon->bb_buf;
3530 jermar 230
}
231
 
3561 svoboda 232
static hash_index_t cache_hash(unsigned long *key)
233
{
234
    return *key & (CACHE_BUCKETS - 1);
235
}
236
 
237
static int cache_compare(unsigned long *key, hash_count_t keys, link_t *item)
238
{
239
    block_t *b = hash_table_get_instance(item, block_t, hash_link);
240
    return b->boff == *key;
241
}
242
 
243
static void cache_remove_callback(link_t *item)
244
{
245
}
246
 
247
static hash_table_operations_t cache_ops = {
248
    .hash = cache_hash,
249
    .compare = cache_compare,
250
    .remove_callback = cache_remove_callback
251
};
252
 
253
int block_cache_init(dev_handle_t dev_handle, size_t size, unsigned blocks)
254
{
255
    devcon_t *devcon = devcon_search(dev_handle);
256
    cache_t *cache;
257
    if (!devcon)
258
        return ENOENT;
259
    if (devcon->cache)
260
        return EEXIST;
261
    cache = malloc(sizeof(cache_t));
262
    if (!cache)
263
        return ENOMEM;
264
 
265
    futex_initialize(&cache->lock, 1);
266
    list_initialize(&cache->free_head);
267
    cache->block_size = size;
268
    cache->block_count = blocks;
269
 
270
    if (!hash_table_create(&cache->block_hash, CACHE_BUCKETS, 1,
271
        &cache_ops)) {
272
        free(cache);
273
        return ENOMEM;
274
    }
275
 
276
    devcon->cache = cache;
277
    return EOK;
278
}
279
 
280
static bool cache_can_grow(cache_t *cache)
281
{
282
    return true;
283
}
284
 
285
static void block_initialize(block_t *b)
286
{
287
    futex_initialize(&b->lock, 1);
288
    b->refcnt = 1;
289
    b->dirty = false;
290
    rwlock_initialize(&b->contents_lock);
291
    link_initialize(&b->free_link);
292
    link_initialize(&b->hash_link);
293
}
294
 
295
/** Instantiate a block in memory and get a reference to it.
296
 *
297
 * @param dev_handle        Device handle of the block device.
298
 * @param boff          Block offset.
3598 svoboda 299
 * @param flags         If BLOCK_FLAGS_NOREAD is specified, block_get()
300
 *              will not read the contents of the block from the
301
 *              device.
3561 svoboda 302
 *
303
 * @return          Block structure.
304
 */
3598 svoboda 305
block_t *block_get(dev_handle_t dev_handle, bn_t boff, int flags)
3561 svoboda 306
{
307
    devcon_t *devcon;
308
    cache_t *cache;
309
    block_t *b;
310
    link_t *l;
311
    unsigned long key = boff;
312
 
313
    devcon = devcon_search(dev_handle);
314
 
315
    assert(devcon);
316
    assert(devcon->cache);
317
 
318
    cache = devcon->cache;
319
    futex_down(&cache->lock);
320
    l = hash_table_find(&cache->block_hash, &key);
321
    if (l) {
322
        /*
323
         * We found the block in the cache.
324
         */
325
        b = hash_table_get_instance(l, block_t, hash_link);
326
        futex_down(&b->lock);
327
        if (b->refcnt++ == 0)
328
            list_remove(&b->free_link);
329
        futex_up(&b->lock);
330
        futex_up(&cache->lock);
331
    } else {
332
        /*
333
         * The block was not found in the cache.
334
         */
335
        int rc;
336
        off_t bufpos = 0;
337
        size_t buflen = 0;
338
        off_t pos = boff * cache->block_size;
339
        bool sync = false;
340
 
341
        if (cache_can_grow(cache)) {
342
            /*
343
             * We can grow the cache by allocating new blocks.
344
             * Should the allocation fail, we fail over and try to
345
             * recycle a block from the cache.
346
             */
347
            b = malloc(sizeof(block_t));
348
            if (!b)
349
                goto recycle;
350
            b->data = malloc(cache->block_size);
351
            if (!b->data) {
352
                free(b);
353
                goto recycle;
354
            }
355
        } else {
356
            /*
357
             * Try to recycle a block from the free list.
358
             */
359
            unsigned long temp_key;
360
recycle:
361
            assert(!list_empty(&cache->free_head));
362
            l = cache->free_head.next;
363
            list_remove(l);
364
            b = hash_table_get_instance(l, block_t, hash_link);
365
            sync = b->dirty;
366
            temp_key = b->boff;
367
            hash_table_remove(&cache->block_hash, &temp_key, 1);
368
        }
369
 
370
        block_initialize(b);
371
        b->dev_handle = dev_handle;
372
        b->size = cache->block_size;
373
        b->boff = boff;
374
        hash_table_insert(&cache->block_hash, &key, &b->hash_link);
375
 
376
        /*
377
         * Lock the block before releasing the cache lock. Thus we don't
378
         * kill concurent operations on the cache while doing I/O on the
379
         * block.
380
         */
381
        futex_down(&b->lock);
382
        futex_up(&cache->lock);
383
 
384
        if (sync) {
385
            /*
386
             * The block is dirty and needs to be written back to
387
             * the device before we can read in the new contents.
388
             */
389
            abort();    /* TODO: block_write() */
390
        }
3598 svoboda 391
        if (!(flags & BLOCK_FLAGS_NOREAD)) {
392
            /*
393
             * The block contains old or no data. We need to read
394
             * the new contents from the device.
395
             */
396
            rc = block_read(dev_handle, &bufpos, &buflen, &pos,
397
                b->data, cache->block_size, cache->block_size);
398
            assert(rc == EOK);
399
        }
3561 svoboda 400
 
401
        futex_up(&b->lock);
402
    }
403
    return b;
404
}
405
 
406
/** Release a reference to a block.
407
 *
408
 * If the last reference is dropped, the block is put on the free list.
409
 *
410
 * @param block     Block of which a reference is to be released.
411
 */
412
void block_put(block_t *block)
413
{
414
    devcon_t *devcon = devcon_search(block->dev_handle);
415
    cache_t *cache;
416
 
417
    assert(devcon);
418
    assert(devcon->cache);
419
 
420
    cache = devcon->cache;
421
    futex_down(&cache->lock);
422
    futex_down(&block->lock);
423
    if (!--block->refcnt) {
424
        /*
425
         * Last reference to the block was dropped, put the block on the
426
         * free list.
427
         */
428
        list_append(&block->free_link, &cache->free_head);
429
    }
430
    futex_up(&block->lock);
431
    futex_up(&cache->lock);
432
}
433
 
3521 jermar 434
/** Read data from a block device.
435
 *
3530 jermar 436
 * @param dev_handle    Device handle of the block device.
3521 jermar 437
 * @param bufpos    Pointer to the first unread valid offset within the
438
 *          communication buffer.
439
 * @param buflen    Pointer to the number of unread bytes that are ready in
440
 *          the communication buffer.
441
 * @param pos       Device position to be read.
442
 * @param dst       Destination buffer.
443
 * @param size      Size of the destination buffer.
444
 * @param block_size    Block size to be used for the transfer.
445
 *
3561 svoboda 446
 * @return      EOK on success or a negative return code on failure.
3521 jermar 447
 */
3561 svoboda 448
int
3530 jermar 449
block_read(int dev_handle, off_t *bufpos, size_t *buflen, off_t *pos, void *dst,
450
    size_t size, size_t block_size)
3521 jermar 451
{
452
    off_t offset = 0;
453
    size_t left = size;
3531 jermar 454
    devcon_t *devcon = devcon_search(dev_handle);
455
    assert(devcon);
3521 jermar 456
 
457
    while (left > 0) {
458
        size_t rd;
459
 
460
        if (*bufpos + left < *buflen)
461
            rd = left;
462
        else
463
            rd = *buflen - *bufpos;
464
 
465
        if (rd > 0) {
466
            /*
467
             * Copy the contents of the communication buffer to the
468
             * destination buffer.
469
             */
3531 jermar 470
            memcpy(dst + offset, devcon->com_area + *bufpos, rd);
3521 jermar 471
            offset += rd;
472
            *bufpos += rd;
473
            *pos += rd;
474
            left -= rd;
475
        }
476
 
477
        if (*bufpos == *buflen) {
478
            /* Refill the communication buffer with a new block. */
479
            ipcarg_t retval;
3531 jermar 480
            int rc = async_req_2_1(devcon->dev_phone, RD_READ_BLOCK,
3521 jermar 481
                *pos / block_size, block_size, &retval);
482
            if ((rc != EOK) || (retval != EOK))
3561 svoboda 483
                return (rc != EOK ? rc : retval);
3521 jermar 484
 
485
            *bufpos = 0;
486
            *buflen = block_size;
487
        }
488
    }
489
 
3561 svoboda 490
    return EOK;
3521 jermar 491
}
492
 
493
/** @}
494
 */