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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.
299
 *
300
 * @return          Block structure.
301
 */
302
block_t *block_get(dev_handle_t dev_handle, off_t boff)
303
{
304
    devcon_t *devcon;
305
    cache_t *cache;
306
    block_t *b;
307
    link_t *l;
308
    unsigned long key = boff;
309
 
310
    devcon = devcon_search(dev_handle);
311
 
312
    assert(devcon);
313
    assert(devcon->cache);
314
 
315
    cache = devcon->cache;
316
    futex_down(&cache->lock);
317
    l = hash_table_find(&cache->block_hash, &key);
318
    if (l) {
319
        /*
320
         * We found the block in the cache.
321
         */
322
        b = hash_table_get_instance(l, block_t, hash_link);
323
        futex_down(&b->lock);
324
        if (b->refcnt++ == 0)
325
            list_remove(&b->free_link);
326
        futex_up(&b->lock);
327
        futex_up(&cache->lock);
328
    } else {
329
        /*
330
         * The block was not found in the cache.
331
         */
332
        int rc;
333
        off_t bufpos = 0;
334
        size_t buflen = 0;
335
        off_t pos = boff * cache->block_size;
336
        bool sync = false;
337
 
338
        if (cache_can_grow(cache)) {
339
            /*
340
             * We can grow the cache by allocating new blocks.
341
             * Should the allocation fail, we fail over and try to
342
             * recycle a block from the cache.
343
             */
344
            b = malloc(sizeof(block_t));
345
            if (!b)
346
                goto recycle;
347
            b->data = malloc(cache->block_size);
348
            if (!b->data) {
349
                free(b);
350
                goto recycle;
351
            }
352
        } else {
353
            /*
354
             * Try to recycle a block from the free list.
355
             */
356
            unsigned long temp_key;
357
recycle:
358
            assert(!list_empty(&cache->free_head));
359
            l = cache->free_head.next;
360
            list_remove(l);
361
            b = hash_table_get_instance(l, block_t, hash_link);
362
            sync = b->dirty;
363
            temp_key = b->boff;
364
            hash_table_remove(&cache->block_hash, &temp_key, 1);
365
        }
366
 
367
        block_initialize(b);
368
        b->dev_handle = dev_handle;
369
        b->size = cache->block_size;
370
        b->boff = boff;
371
        hash_table_insert(&cache->block_hash, &key, &b->hash_link);
372
 
373
        /*
374
         * Lock the block before releasing the cache lock. Thus we don't
375
         * kill concurent operations on the cache while doing I/O on the
376
         * block.
377
         */
378
        futex_down(&b->lock);
379
        futex_up(&cache->lock);
380
 
381
        if (sync) {
382
            /*
383
             * The block is dirty and needs to be written back to
384
             * the device before we can read in the new contents.
385
             */
386
            abort();    /* TODO: block_write() */
387
        }
388
        /*
389
         * The block contains old or no data. We need to read the new
390
         * contents from the device.
391
         */
392
        rc = block_read(dev_handle, &bufpos, &buflen, &pos, b->data,
393
            cache->block_size, cache->block_size);
394
        assert(rc == EOK);
395
 
396
        futex_up(&b->lock);
397
    }
398
    return b;
399
}
400
 
401
/** Release a reference to a block.
402
 *
403
 * If the last reference is dropped, the block is put on the free list.
404
 *
405
 * @param block     Block of which a reference is to be released.
406
 */
407
void block_put(block_t *block)
408
{
409
    devcon_t *devcon = devcon_search(block->dev_handle);
410
    cache_t *cache;
411
 
412
    assert(devcon);
413
    assert(devcon->cache);
414
 
415
    cache = devcon->cache;
416
    futex_down(&cache->lock);
417
    futex_down(&block->lock);
418
    if (!--block->refcnt) {
419
        /*
420
         * Last reference to the block was dropped, put the block on the
421
         * free list.
422
         */
423
        list_append(&block->free_link, &cache->free_head);
424
    }
425
    futex_up(&block->lock);
426
    futex_up(&cache->lock);
427
}
428
 
3521 jermar 429
/** Read data from a block device.
430
 *
3530 jermar 431
 * @param dev_handle    Device handle of the block device.
3521 jermar 432
 * @param bufpos    Pointer to the first unread valid offset within the
433
 *          communication buffer.
434
 * @param buflen    Pointer to the number of unread bytes that are ready in
435
 *          the communication buffer.
436
 * @param pos       Device position to be read.
437
 * @param dst       Destination buffer.
438
 * @param size      Size of the destination buffer.
439
 * @param block_size    Block size to be used for the transfer.
440
 *
3561 svoboda 441
 * @return      EOK on success or a negative return code on failure.
3521 jermar 442
 */
3561 svoboda 443
int
3530 jermar 444
block_read(int dev_handle, off_t *bufpos, size_t *buflen, off_t *pos, void *dst,
445
    size_t size, size_t block_size)
3521 jermar 446
{
447
    off_t offset = 0;
448
    size_t left = size;
3531 jermar 449
    devcon_t *devcon = devcon_search(dev_handle);
450
    assert(devcon);
3521 jermar 451
 
452
    while (left > 0) {
453
        size_t rd;
454
 
455
        if (*bufpos + left < *buflen)
456
            rd = left;
457
        else
458
            rd = *buflen - *bufpos;
459
 
460
        if (rd > 0) {
461
            /*
462
             * Copy the contents of the communication buffer to the
463
             * destination buffer.
464
             */
3531 jermar 465
            memcpy(dst + offset, devcon->com_area + *bufpos, rd);
3521 jermar 466
            offset += rd;
467
            *bufpos += rd;
468
            *pos += rd;
469
            left -= rd;
470
        }
471
 
472
        if (*bufpos == *buflen) {
473
            /* Refill the communication buffer with a new block. */
474
            ipcarg_t retval;
3531 jermar 475
            int rc = async_req_2_1(devcon->dev_phone, RD_READ_BLOCK,
3521 jermar 476
                *pos / block_size, block_size, &retval);
477
            if ((rc != EOK) || (retval != EOK))
3561 svoboda 478
                return (rc != EOK ? rc : retval);
3521 jermar 479
 
480
            *bufpos = 0;
481
            *buflen = block_size;
482
        }
483
    }
484
 
3561 svoboda 485
    return EOK;
3521 jermar 486
}
487
 
488
/** @}
489
 */