[SOLVED] CS代考计算机代写 #include “devices/block.h”

#include “devices/block.h”
#include #include
#include
#include “devices/ide.h”
#include “threads/malloc.h”

/* A block device. */
struct block
{
struct list_elem list_elem; /* Element in all_blocks. */

char name[16];/* Block device name. */
enum block_type type;/* Type of block device. */
block_sector_t size; /* Size in sectors. */

const struct block_operations *ops;/* Driver operations. */
void *aux;/* Extra data owned by driver. */

unsigned long long read_cnt;/* Number of sectors read. */
unsigned long long write_cnt; /* Number of sectors written. */
};

/* List of all block devices. */
static struct list all_blocks = LIST_INITIALIZER (all_blocks);

/* The block block assigned to each Pintos role. */
static struct block *block_by_role[BLOCK_ROLE_CNT];

static struct block *list_elem_to_block (struct list_elem *);

/* Returns a human-readable name for the given block device
TYPE. */
const char *
block_type_name (enum block_type type)
{
static const char *block_type_names[BLOCK_CNT] =
{
“kernel”,
“filesys”,
“scratch”,
“swap”,
“raw”,
“foreign”,
};

ASSERT (type < BLOCK_CNT);return block_type_names[type];}/* Returns the block device fulfilling the given ROLE, or a null pointer if no block device has been assigned that role. */struct block *block_get_role (enum block_type role){ASSERT (role < BLOCK_ROLE_CNT);return block_by_role[role];}/* Assigns BLOCK the given ROLE. */voidblock_set_role (enum block_type role, struct block *block){ASSERT (role < BLOCK_ROLE_CNT);block_by_role[role] = block;}/* Returns the first block device in kernel probe order, or a null pointer if no block devices are registered. */struct block *block_first (void){return list_elem_to_block (list_begin (&all_blocks));}/* Returns the block device following BLOCK in kernel probe order, or a null pointer if BLOCK is the last block device. */struct block *block_next (struct block *block){return list_elem_to_block (list_next (&block->list_elem));
}

/* Returns the block device with the given NAME, or a null
pointer if no block device has that name. */
struct block *
block_get_by_name (const char *name)
{
struct list_elem *e;

for (e = list_begin (&all_blocks); e != list_end (&all_blocks);
e = list_next (e))
{
struct block *block = list_entry (e, struct block, list_elem);
if (!strcmp (name, block->name))
return block;
}

return NULL;
}

/* Verifies that SECTOR is a valid offset within BLOCK.
Panics if not. */
static void
check_sector (struct block *block, block_sector_t sector)
{
if (sector >= block->size)
{
/* We do not use ASSERT because we want to panic here
regardless of whether NDEBUG is defined. */
PANIC (“Access past end of device %s (sector=%”PRDSNu”, ”
“size=%”PRDSNu”)
”, block_name (block), sector, block->size);
}
}

/* Reads sector SECTOR from BLOCK into BUFFER, which must
have room for BLOCK_SECTOR_SIZE bytes.
Internally synchronizes accesses to block devices, so external
per-block device locking is unneeded. */
void
block_read (struct block *block, block_sector_t sector, void *buffer)
{
check_sector (block, sector);
block->ops->read (block->aux, sector, buffer);
block->read_cnt++;
}

/* Write sector SECTOR to BLOCK from BUFFER, which must contain
BLOCK_SECTOR_SIZE bytes.Returns after the block device has
acknowledged receiving the data.
Internally synchronizes accesses to block devices, so external
per-block device locking is unneeded. */
void
block_write (struct block *block, block_sector_t sector, const void *buffer)
{
check_sector (block, sector);
ASSERT (block->type != BLOCK_FOREIGN);
block->ops->write (block->aux, sector, buffer);
block->write_cnt++;
}

/* Returns the number of sectors in BLOCK. */
block_sector_t
block_size (struct block *block)
{
return block->size;
}

/* Returns BLOCK’s name (e.g. “hda”). */
const char *
block_name (struct block *block)
{
return block->name;
}

/* Returns BLOCK’s type. */
enum block_type
block_type (struct block *block)
{
return block->type;
}

/* Prints statistics for each block device used for a Pintos role. */
void
block_print_stats (void)
{
int i;

for (i = 0; i < BLOCK_ROLE_CNT; i++){struct block *block = block_by_role[i];if (block != NULL){printf (“%s (%s): %llu reads, %llu writes
“,block->name, block_type_name (block->type),
block->read_cnt, block->write_cnt);
}
}
}

/* Registers a new block device with the given NAME.If
EXTRA_INFO is non-null, it is printed as part of a user
message.The block device’s SIZE in sectors and its TYPE must
be provided, as well as the it operation functions OPS, which
will be passed AUX in each function call. */
struct block *
block_register (const char *name, enum block_type type,
const char *extra_info, block_sector_t size,
const struct block_operations *ops, void *aux)
{
struct block *block = malloc (sizeof *block);
if (block == NULL)
PANIC (“Failed to allocate memory for block device descriptor”);

list_push_back (&all_blocks, &block->list_elem);
strlcpy (block->name, name, sizeof block->name);
block->type = type;
block->size = size;
block->ops = ops;
block->aux = aux;
block->read_cnt = 0;
block->write_cnt = 0;

printf (“%s: %’”PRDSNu” sectors (“, block->name, block->size);
print_human_readable_size ((uint64_t) block->size * BLOCK_SECTOR_SIZE);
printf (“)”);
if (extra_info != NULL)
printf (“, %s”, extra_info);
printf (“
”);

return block;
}
�
/* Returns the block device corresponding to LIST_ELEM, or a null
pointer if LIST_ELEM is the list end of all_blocks. */
static struct block *
list_elem_to_block (struct list_elem *list_elem)
{
return (list_elem != list_end (&all_blocks)
? list_entry (list_elem, struct block, list_elem)
: NULL);
}