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/*
* Copyright (c) 2008 Jakub Jermar
* Copyright (c) 2008 Martin Decky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup libblock
* @{
*/
/**
* @file
* @brief
*/
#include "libblock.h"
#include "../../srv/vfs/vfs.h"
#include "../../srv/rd/rd.h"
#include <ipc/devmap.h>
#include <ipc/services.h>
#include <errno.h>
#include <sys/mman.h>
#include <async.h>
#include <ipc/ipc.h>
#include <as.h>
#include <assert.h>
#include <futex.h>
#include <libadt/list.h>
#include <libadt/hash_table.h>
/** Lock protecting the device connection list */
static futex_t dcl_lock = FUTEX_INITIALIZER;
/** Device connection list head. */
static LIST_INITIALIZE(dcl_head);
#define CACHE_BUCKETS_LOG2 10
#define CACHE_BUCKETS (1 << CACHE_BUCKETS_LOG2)
typedef struct {
futex_t lock;
size_t block_size; /**< Block size. */
unsigned block_count; /**< Total number of blocks. */
hash_table_t block_hash;
link_t free_head;
} cache_t;
typedef struct {
link_t link;
int dev_handle;
int dev_phone;
void *com_area;
size_t com_size;
void *bb_buf;
off_t bb_off;
size_t bb_size;
cache_t *cache;
} devcon_t;
static devcon_t *devcon_search(dev_handle_t dev_handle)
{
link_t *cur;
futex_down(&dcl_lock);
for (cur = dcl_head.next; cur != &dcl_head; cur = cur->next) {
devcon_t *devcon = list_get_instance(cur, devcon_t, link);
if (devcon->dev_handle == dev_handle) {
futex_up(&dcl_lock);
return devcon;
}
}
futex_up(&dcl_lock);
return NULL;
}
static int devcon_add(dev_handle_t dev_handle, int dev_phone, void *com_area,
size_t com_size)
{
link_t *cur;
devcon_t *devcon;
devcon = malloc(sizeof(devcon_t));
if (!devcon)
return ENOMEM;
link_initialize(&devcon->link);
devcon->dev_handle = dev_handle;
devcon->dev_phone = dev_phone;
devcon->com_area = com_area;
devcon->com_size = com_size;
devcon->bb_buf = NULL;
devcon->bb_off = 0;
devcon->bb_size = 0;
devcon->cache = NULL;
futex_down(&dcl_lock);
for (cur = dcl_head.next; cur != &dcl_head; cur = cur->next) {
devcon_t *d = list_get_instance(cur, devcon_t, link);
if (d->dev_handle == dev_handle) {
futex_up(&dcl_lock);
free(devcon);
return EEXIST;
}
}
list_append(&devcon->link, &dcl_head);
futex_up(&dcl_lock);
return EOK;
}
static void devcon_remove(devcon_t *devcon)
{
futex_down(&dcl_lock);
list_remove(&devcon->link);
futex_up(&dcl_lock);
}
int block_init(dev_handle_t dev_handle, size_t com_size)
{
int rc;
int dev_phone;
void *com_area;
com_area = mmap(NULL, com_size, PROTO_READ | PROTO_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
if (!com_area) {
return ENOMEM;
}
dev_phone = ipc_connect_me_to(PHONE_NS, SERVICE_DEVMAP,
DEVMAP_CONNECT_TO_DEVICE, dev_handle);
if (dev_phone < 0) {
munmap(com_area, com_size);
return dev_phone;
}
rc = ipc_share_out_start(dev_phone, com_area,
AS_AREA_READ | AS_AREA_WRITE);
if (rc != EOK) {
munmap(com_area, com_size);
ipc_hangup(dev_phone);
return rc;
}
rc = devcon_add(dev_handle, dev_phone, com_area, com_size);
if (rc != EOK) {
munmap(com_area, com_size);
ipc_hangup(dev_phone);
return rc;
}
return EOK;
}
void block_fini(dev_handle_t dev_handle)
{
devcon_t *devcon = devcon_search(dev_handle);
assert(devcon);
devcon_remove(devcon);
if (devcon->bb_buf)
free(devcon->bb_buf);
if (devcon->cache) {
hash_table_destroy(&devcon->cache->block_hash);
free(devcon->cache);
}
munmap(devcon->com_area, devcon->com_size);
ipc_hangup(devcon->dev_phone);
free(devcon);
}
int block_bb_read(dev_handle_t dev_handle, off_t off, size_t size)
{
void *bb_buf;
int rc;
devcon_t *devcon = devcon_search(dev_handle);
if (!devcon)
return ENOENT;
if (devcon->bb_buf)
return EEXIST;
bb_buf = malloc(size);
if (!bb_buf)
return ENOMEM;
off_t bufpos = 0;
size_t buflen = 0;
rc = block_read(dev_handle, &bufpos, &buflen, &off,
bb_buf, size, size);
if (rc != EOK) {
free(bb_buf);
return rc;
}
devcon->bb_buf = bb_buf;
devcon->bb_off = off;
devcon->bb_size = size;
return EOK;
}
void *block_bb_get(dev_handle_t dev_handle)
{
devcon_t *devcon = devcon_search(dev_handle);
assert(devcon);
return devcon->bb_buf;
}
static hash_index_t cache_hash(unsigned long *key)
{
return *key & (CACHE_BUCKETS - 1);
}
static int cache_compare(unsigned long *key, hash_count_t keys, link_t *item)
{
block_t *b = hash_table_get_instance(item, block_t, hash_link);
return b->boff == *key;
}
static void cache_remove_callback(link_t *item)
{
}
static hash_table_operations_t cache_ops = {
.hash = cache_hash,
.compare = cache_compare,
.remove_callback = cache_remove_callback
};
int block_cache_init(dev_handle_t dev_handle, size_t size, unsigned blocks)
{
devcon_t *devcon = devcon_search(dev_handle);
cache_t *cache;
if (!devcon)
return ENOENT;
if (devcon->cache)
return EEXIST;
cache = malloc(sizeof(cache_t));
if (!cache)
return ENOMEM;
futex_initialize(&cache->lock, 1);
list_initialize(&cache->free_head);
cache->block_size = size;
cache->block_count = blocks;
if (!hash_table_create(&cache->block_hash, CACHE_BUCKETS, 1,
&cache_ops)) {
free(cache);
return ENOMEM;
}
devcon->cache = cache;
return EOK;
}
static bool cache_can_grow(cache_t *cache)
{
return true;
}
static void block_initialize(block_t *b)
{
futex_initialize(&b->lock, 1);
b->refcnt = 1;
b->dirty = false;
rwlock_initialize(&b->contents_lock);
link_initialize(&b->free_link);
link_initialize(&b->hash_link);
}
/** Instantiate a block in memory and get a reference to it.
*
* @param dev_handle Device handle of the block device.
* @param boff Block offset.
*
* @return Block structure.
*/
block_t *block_get(dev_handle_t dev_handle, bn_t boff)
{
devcon_t *devcon;
cache_t *cache;
block_t *b;
link_t *l;
unsigned long key = boff;
devcon = devcon_search(dev_handle);
assert(devcon);
assert(devcon->cache);
cache = devcon->cache;
futex_down(&cache->lock);
l = hash_table_find(&cache->block_hash, &key);
if (l) {
/*
* We found the block in the cache.
*/
b = hash_table_get_instance(l, block_t, hash_link);
futex_down(&b->lock);
if (b->refcnt++ == 0)
list_remove(&b->free_link);
futex_up(&b->lock);
futex_up(&cache->lock);
} else {
/*
* The block was not found in the cache.
*/
int rc;
off_t bufpos = 0;
size_t buflen = 0;
off_t pos = boff * cache->block_size;
bool sync = false;
if (cache_can_grow(cache)) {
/*
* We can grow the cache by allocating new blocks.
* Should the allocation fail, we fail over and try to
* recycle a block from the cache.
*/
b = malloc(sizeof(block_t));
if (!b)
goto recycle;
b->data = malloc(cache->block_size);
if (!b->data) {
free(b);
goto recycle;
}
} else {
/*
* Try to recycle a block from the free list.
*/
unsigned long temp_key;
recycle:
assert(!list_empty(&cache->free_head));
l = cache->free_head.next;
list_remove(l);
b = hash_table_get_instance(l, block_t, hash_link);
sync = b->dirty;
temp_key = b->boff;
hash_table_remove(&cache->block_hash, &temp_key, 1);
}
block_initialize(b);
b->dev_handle = dev_handle;
b->size = cache->block_size;
b->boff = boff;
hash_table_insert(&cache->block_hash, &key, &b->hash_link);
/*
* Lock the block before releasing the cache lock. Thus we don't
* kill concurent operations on the cache while doing I/O on the
* block.
*/
futex_down(&b->lock);
futex_up(&cache->lock);
if (sync) {
/*
* The block is dirty and needs to be written back to
* the device before we can read in the new contents.
*/
abort(); /* TODO: block_write() */
}
/*
* The block contains old or no data. We need to read the new
* contents from the device.
*/
rc = block_read(dev_handle, &bufpos, &buflen, &pos, b->data,
cache->block_size, cache->block_size);
assert(rc == EOK);
futex_up(&b->lock);
}
return b;
}
/** Release a reference to a block.
*
* If the last reference is dropped, the block is put on the free list.
*
* @param block Block of which a reference is to be released.
*/
void block_put(block_t *block)
{
devcon_t *devcon = devcon_search(block->dev_handle);
cache_t *cache;
assert(devcon);
assert(devcon->cache);
cache = devcon->cache;
futex_down(&cache->lock);
futex_down(&block->lock);
if (!--block->refcnt) {
/*
* Last reference to the block was dropped, put the block on the
* free list.
*/
list_append(&block->free_link, &cache->free_head);
}
futex_up(&block->lock);
futex_up(&cache->lock);
}
/** Read data from a block device.
*
* @param dev_handle Device handle of the block device.
* @param bufpos Pointer to the first unread valid offset within the
* communication buffer.
* @param buflen Pointer to the number of unread bytes that are ready in
* the communication buffer.
* @param pos Device position to be read.
* @param dst Destination buffer.
* @param size Size of the destination buffer.
* @param block_size Block size to be used for the transfer.
*
* @return EOK on success or a negative return code on failure.
*/
int
block_read(int dev_handle, off_t *bufpos, size_t *buflen, off_t *pos, void *dst,
size_t size, size_t block_size)
{
off_t offset = 0;
size_t left = size;
devcon_t *devcon = devcon_search(dev_handle);
assert(devcon);
while (left > 0) {
size_t rd;
if (*bufpos + left < *buflen)
rd = left;
else
rd = *buflen - *bufpos;
if (rd > 0) {
/*
* Copy the contents of the communication buffer to the
* destination buffer.
*/
memcpy(dst + offset, devcon->com_area + *bufpos, rd);
offset += rd;
*bufpos += rd;
*pos += rd;
left -= rd;
}
if (*bufpos == *buflen) {
/* Refill the communication buffer with a new block. */
ipcarg_t retval;
int rc = async_req_2_1(devcon->dev_phone, RD_READ_BLOCK,
*pos / block_size, block_size, &retval);
if ((rc != EOK) || (retval != EOK))
return (rc != EOK ? rc : retval);
*bufpos = 0;
*buflen = block_size;
}
}
return EOK;
}
/** @}
*/