mars/mars_if.c
Thomas Schoebel-Theuer bf5935a356 import mars-117.tgz
2013-01-08 15:54:38 +01:00

864 lines
21 KiB
C

// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
/* Interface to a Linux device.
* 1 Input, 0 Outputs.
*/
//#define BRICK_DEBUGGING
//#define MARS_DEBUGGING
//#define IO_DEBUGGING
#define REQUEST_MERGING
//#define ALWAYS_UNPLUG false
#define ALWAYS_UNPLUG true
#define PREFETCH_LEN PAGE_SIZE
//#define FRONT_MERGE // FIXME: this does not work.
// low-level device parameters
//#define USE_MAX_SECTORS (MARS_MAX_SEGMENT_SIZE >> 9)
//#define USE_MAX_PHYS_SEGMENTS (MARS_MAX_SEGMENT_SIZE >> 9)
//#define USE_MAX_SEGMENT_SIZE MARS_MAX_SEGMENT_SIZE
//#define USE_LOGICAL_BLOCK_SIZE 512
//#define USE_SEGMENT_BOUNDARY (PAGE_SIZE-1)
//#define USE_QUEUE_ORDERED QUEUE_ORDERED_DRAIN
//#define USE_CONGESTED_FN
#define USE_MERGE_BVEC
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/major.h>
#include <linux/genhd.h>
#include <linux/blkdev.h>
#include "mars.h"
///////////////////////// own type definitions ////////////////////////
#include "mars_if.h"
///////////////////////// own static definitions ////////////////////////
// TODO: check bounds, ensure that free minor numbers are recycled
static int device_minor = 0;
//////////////// object / aspect constructors / destructors ///////////////
///////////////////////// linux operations ////////////////////////
/* callback
*/
static
void if_endio(struct generic_callback *cb)
{
struct if_mref_aspect *mref_a = cb->cb_private;
struct if_input *input;
struct bio *bio;
int k;
int rw = 0;
int error;
if (unlikely(!mref_a)) {
MARS_FAT("callback with no mref_a called. something is very wrong here!\n");
return;
}
mars_trace(mref_a->object, "if_endio");
mars_log_trace(mref_a->object);
for (k = 0; k < mref_a->bio_count; k++) {
bio = mref_a->orig_bio[k];
mref_a->orig_bio[k] = NULL;
if (unlikely(!bio)) {
MARS_FAT("callback with no bio called (k = %d). something is very wrong here!\n", k);
continue;
}
rw = bio->bi_rw & 1;
CHECK_ATOMIC(&bio->bi_comp_cnt, 1);
if (!atomic_dec_and_test(&bio->bi_comp_cnt)) {
continue;
}
#if 1
if (mref_a->is_kmapped) {
struct bio_vec *bvec;
int i;
bio_for_each_segment(bvec, bio, i) {
MARS_IO("kunmap %p\n", bvec->bv_page);
kunmap(bvec->bv_page);
}
}
#endif
error = mref_a->cb.cb_error;
if (unlikely(error < 0)) {
MARS_ERR("NYI: error=%d RETRY LOGIC %u\n", error, bio->bi_size);
} else { // bio conventions are slightly different...
error = 0;
bio->bi_size = 0;
}
bio_endio(bio, error);
bio_put(bio);
}
input = mref_a->input;
if (input) {
atomic_dec(&input->flying_count);
if (rw) {
atomic_dec(&input->write_flying_count);
} else {
atomic_dec(&input->read_flying_count);
}
}
}
/* Kick off plugged mrefs
*/
static
void _if_unplug(struct if_input *input)
{
//struct if_brick *brick = input->brick;
LIST_HEAD(tmp_list);
unsigned long flags;
might_sleep();
down(&input->kick_sem);
traced_lock(&input->req_lock, flags);
#ifdef USE_TIMER
del_timer(&input->timer);
#endif
if (!list_empty(&input->plug_anchor)) {
// move over the whole list
list_replace_init(&input->plug_anchor, &tmp_list);
atomic_set(&input->plugged_count, 0);
}
traced_unlock(&input->req_lock, flags);
up(&input->kick_sem);
while (!list_empty(&tmp_list)) {
struct if_mref_aspect *mref_a;
struct mref_object *mref;
int hash_index;
unsigned long flags;
mref_a = container_of(tmp_list.next, struct if_mref_aspect, plug_head);
list_del_init(&mref_a->plug_head);
hash_index = mref_a->hash_index;
traced_lock(&input->hash_lock[hash_index], flags);
list_del_init(&mref_a->hash_head);
traced_unlock(&input->hash_lock[hash_index], flags);
mref = mref_a->object;
if (unlikely(mref_a->current_len > mref_a->max_len)) {
MARS_ERR("request len %d > %d\n", mref_a->current_len, mref_a->max_len);
}
mref->ref_len = mref_a->current_len;
mars_trace(mref, "if_unplug");
atomic_inc(&input->flying_count);
if (mref->ref_rw) {
atomic_inc(&input->write_flying_count);
} else {
atomic_inc(&input->read_flying_count);
}
GENERIC_INPUT_CALL(input, mref_io, mref);
GENERIC_INPUT_CALL(input, mref_put, mref);
}
}
#ifdef USE_TIMER
static
void if_timer(unsigned long data)
{
_if_unplug((void*)data);
}
#endif
/* accept a linux bio, convert to mref and call buf_io() on it.
*/
static int if_make_request(struct request_queue *q, struct bio *bio)
{
struct if_input *input;
struct if_brick *brick = NULL;
struct mref_object *mref = NULL;
struct if_mref_aspect *mref_a;
struct generic_callback *cb;
struct bio_vec *bvec;
int i;
bool assigned = false;
const bool unplug = bio_rw_flagged(bio, BIO_RW_UNPLUG);
const bool barrier = ((bio->bi_rw & 1) != READ && bio_rw_flagged(bio, BIO_RW_BARRIER));
loff_t pos = ((loff_t)bio->bi_sector) << 9; // TODO: make dynamic
int rw = bio_data_dir(bio);
int total_len = bio->bi_size;
int error = -ENOSYS;
MARS_IO("bio %p size = %d\n", bio, bio->bi_size);
might_sleep();
input = q->queuedata;
if (unlikely(!input))
goto err;
if (unlikely(!bio_sectors(bio))) {
atomic_inc(&input->total_empty_count);
_if_unplug(input);
/* THINK: usually this happens only at write barriers.
* We have no "barrier" operation in MARS, since
* callback semantics should always denote
* "writethrough accomplished".
* In case of exceptional semantics, we need to do
* something here. For now, we do just nothing.
*/
bio_endio(bio, 0);
return 0;
}
if (rw) {
atomic_inc(&input->total_write_count);
} else {
atomic_inc(&input->total_read_count);
}
brick = input->brick;
if (unlikely(!brick))
goto err;
/* Get a reference to the bio.
* Will be released after bio_endio().
*/
atomic_inc(&bio->bi_cnt);
/* FIXME: THIS IS PROVISIONARY (use event instead)
*/
while (unlikely(!brick->power.led_on)) {
msleep(2 * HZ);
}
_CHECK_ATOMIC(&bio->bi_comp_cnt, !=, 0);
atomic_set(&bio->bi_comp_cnt, 0);
#ifdef IO_DEBUGGING
{
const unsigned short prio = bio_prio(bio);
const bool sync = bio_rw_flagged(bio, BIO_RW_SYNCIO);
const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK;
MARS_IO("BIO rw = %lx len = %d prio = %d sync = %d unplug = %d ff = %d\n", bio->bi_rw, bio->bi_size, prio, sync, unplug, ff);
}
#endif
down(&input->kick_sem);
bio_for_each_segment(bvec, bio, i) {
struct page *page = bvec->bv_page;
int bv_len = bvec->bv_len;
int offset = bvec->bv_offset;
void *data;
data = kmap(page);
MARS_IO("page = %p data = %p\n", page, data);
error = -EINVAL;
if (unlikely(!data))
break;
data += offset;
while (bv_len > 0) {
struct list_head *tmp;
int hash_index;
int this_len = 0;
unsigned long flags;
mref = NULL;
mref_a = NULL;
MARS_IO("rw = %d i = %d pos = %lld bv_page = %p bv_offset = %d data = %p bv_len = %d\n", rw, i, pos, bvec->bv_page, bvec->bv_offset, data, bv_len);
hash_index = (pos / IF_HASH_CHUNK) % IF_HASH_MAX;
#ifdef REQUEST_MERGING
traced_lock(&input->hash_lock[hash_index], flags);
for (tmp = input->hash_table[hash_index].next; tmp != &input->hash_table[hash_index]; tmp = tmp->next) {
struct if_mref_aspect *tmp_a;
struct mref_object *tmp_mref;
int i;
tmp_a = container_of(tmp, struct if_mref_aspect, hash_head);
tmp_mref = tmp_a->object;
if (tmp_a->orig_page != page || tmp_mref->ref_rw != rw || tmp_a->bio_count >= MAX_BIO || tmp_a->current_len + bv_len > tmp_a->max_len) {
continue;
}
if (tmp_mref->ref_data + tmp_a->current_len == data) {
goto merge_end;
#ifdef FRONT_MERGE // FIXME: this cannot work. ref_data must never be changed. pre-allocate from offset 0 instead.
} else if (data + bv_len == tmp_mref->ref_data) {
goto merge_front;
#endif
}
continue;
#ifdef FRONT_MERGE // FIXME: this cannot work. ref_data must never be changed. pre-allocate from offset 0 instead.
merge_front:
tmp_mref->ref_data = data;
#endif
merge_end:
tmp_a->current_len += bv_len;
mref = tmp_mref;
mref_a = tmp_a;
this_len = bv_len;
if (barrier) {
mref->ref_skip_sync = false;
}
for (i = 0; i < mref_a->bio_count; i++) {
if (mref_a->orig_bio[i] == bio) {
goto unlock;
}
}
CHECK_ATOMIC(&bio->bi_comp_cnt, 0);
atomic_inc(&bio->bi_comp_cnt);
mref_a->orig_bio[mref_a->bio_count++] = bio;
assigned = true;
goto unlock;
} // foreach hash collision list member
unlock:
traced_unlock(&input->hash_lock[hash_index], flags);
#endif
if (!mref) {
int prefetch_len;
error = -ENOMEM;
mref = if_alloc_mref(&brick->hidden_output, &input->mref_object_layout);
if (unlikely(!mref)) {
up(&input->kick_sem);
goto err;
}
mref_a = if_mref_get_aspect(&brick->hidden_output, mref);
if (unlikely(!mref_a)) {
up(&input->kick_sem);
goto err;
}
#ifdef PREFETCH_LEN
prefetch_len = PREFETCH_LEN - offset;
#if 1
// TODO: this restriction is too strong to be useful for performance boosts. Do better.
if (prefetch_len > total_len) {
prefetch_len = total_len;
}
#endif
if (pos + prefetch_len > input->info.current_size) {
prefetch_len = input->info.current_size - pos;
}
if (prefetch_len < bv_len) {
prefetch_len = bv_len;
}
#else
prefetch_len = bv_len;
#endif
cb = &mref_a->cb;
cb->cb_fn = if_endio;
cb->cb_private = mref_a;
cb->cb_error = 0;
cb->cb_prev = NULL;
mref->ref_cb = cb;
mref_a->input = input;
mref->ref_rw = mref->ref_may_write = rw;
mref->ref_pos = pos;
mref->ref_len = prefetch_len;
mref->ref_data = data; // direct IO
mref_a->orig_page = page;
mref_a->is_kmapped = true;
error = GENERIC_INPUT_CALL(input, mref_get, mref);
if (unlikely(error < 0)) {
up(&input->kick_sem);
goto err;
}
mars_trace(mref, "if_start");
this_len = mref->ref_len; // now may be shorter than originally requested.
mref_a->max_len = this_len;
if (this_len > bv_len) {
this_len = bv_len;
}
mref_a->current_len = this_len;
if (rw) {
atomic_inc(&input->total_mref_write_count);
} else {
atomic_inc(&input->total_mref_read_count);
}
CHECK_ATOMIC(&bio->bi_comp_cnt, 0);
atomic_inc(&bio->bi_comp_cnt);
mref_a->orig_bio[0] = bio;
mref_a->bio_count = 1;
assigned = true;
if (brick->skip_sync && !barrier) {
mref->ref_skip_sync = true;
}
atomic_inc(&input->plugged_count);
mref_a->hash_index = hash_index;
traced_lock(&input->hash_lock[hash_index], flags);
list_add_tail(&mref_a->hash_head, &input->hash_table[hash_index]);
traced_unlock(&input->hash_lock[hash_index], flags);
traced_lock(&input->req_lock, flags);
list_add_tail(&mref_a->plug_head, &input->plug_anchor);
traced_unlock(&input->req_lock, flags);
} // !mref
pos += this_len;
data += this_len;
bv_len -= this_len;
total_len -= this_len;
} // while bv_len > 0
} // foreach bvec
up(&input->kick_sem);
if (likely(!total_len)) {
error = 0;
} else {
MARS_ERR("bad rest len = %d\n", total_len);
}
err:
if (error < 0) {
MARS_ERR("cannot submit request from bio, status=%d\n", error);
if (assigned) {
//... cleanup the mess NYI
} else {
bio_endio(bio, error);
}
}
if (ALWAYS_UNPLUG || unplug ||
(brick && brick->max_plugged > 0 && atomic_read(&input->plugged_count) > brick->max_plugged)) {
_if_unplug(input);
}
#ifdef USE_TIMER
else {
unsigned long flags;
traced_lock(&input->req_lock, flags);
if (timer_pending(&input->timer)) {
del_timer(&input->timer);
}
input->timer.function = if_timer;
input->timer.data = (unsigned long)input;
input->timer.expires = jiffies + HZ/10;
add_timer(&input->timer);
traced_unlock(&input->req_lock, flags);
}
#endif
return error;
}
static int if_open(struct block_device *bdev, fmode_t mode)
{
struct if_input *input = bdev->bd_disk->private_data;
atomic_inc(&input->open_count);
MARS_INF("----------------------- OPEN %d ------------------------------\n", atomic_read(&input->open_count));
return 0;
}
static int if_release(struct gendisk *gd, fmode_t mode)
{
struct if_input *input = gd->private_data;
int max = 0;
int nr;
MARS_INF("----------------------- CLOSE %d ------------------------------\n", atomic_read(&input->open_count));
while ((nr = atomic_read(&input->flying_count)) > 0) {
MARS_INF("%d IO requests not yet completed\n", nr);
if (max++ > 10)
break;
msleep(2000);
}
if (atomic_dec_and_test(&input->open_count)) {
struct if_brick *brick = input->brick;
brick->has_closed = true;
mars_trigger();
}
return 0;
}
//static
void if_unplug(struct request_queue *q)
{
int was_plugged = 1;
#if 1
spin_lock_irq(q->queue_lock);
was_plugged = blk_remove_plug(q);
spin_unlock_irq(q->queue_lock);
#else
queue_flag_clear_unlocked(QUEUE_FLAG_PLUGGED, q);
#endif
MARS_IO("UNPLUG %d\n", was_plugged);
if (true || was_plugged) {
struct if_input *input = q->queuedata;
_if_unplug(input);
}
}
//static
int mars_congested(void *data, int bdi_bits)
{
struct if_input *input = data;
int ret = 0;
if (bdi_bits & (1 << BDI_sync_congested) &&
atomic_read(&input->flying_count) > 0) {
ret |= (1 << BDI_sync_congested);
}
return ret;
}
static
int mars_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec)
{
unsigned int bio_size = bvm->bi_size;
if (!bio_size) {
return bvec->bv_len;
}
return 128;
}
static const struct block_device_operations if_blkdev_ops = {
.owner = THIS_MODULE,
.open = if_open,
.release = if_release,
};
static int if_switch(struct if_brick *brick)
{
struct if_input *input = brick->inputs[0];
struct request_queue *q;
struct gendisk *disk;
int minor;
unsigned long capacity;
int status;
if (brick->power.button) {
mars_power_led_off((void*)brick, false);
status = GENERIC_INPUT_CALL(input, mars_get_info, &input->info);
if (status < 0) {
MARS_ERR("cannot get device info, status=%d\n", status);
return status;
}
capacity = input->info.current_size >> 9; // TODO: make this dynamic
q = blk_alloc_queue(GFP_MARS);
if (!q) {
MARS_ERR("cannot allocate device request queue\n");
return -ENOMEM;
}
q->queuedata = input;
input->q = q;
disk = alloc_disk(1);
if (!disk) {
MARS_ERR("cannot allocate gendisk\n");
return -ENOMEM;
}
minor = device_minor++; //TODO: protect against races (e.g. atomic_t)
disk->queue = q;
disk->major = MARS_MAJOR; //TODO: make this dynamic for >256 devices
disk->first_minor = minor;
disk->fops = &if_blkdev_ops;
//snprintf(disk->disk_name, sizeof(disk->disk_name), "mars%d", minor);
snprintf(disk->disk_name, sizeof(disk->disk_name), "mars/%s", brick->brick_name);
MARS_DBG("created device name %s\n", disk->disk_name);
disk->private_data = input;
set_capacity(disk, capacity);
blk_queue_make_request(q, if_make_request);
#ifdef USE_MAX_SECTORS
blk_queue_max_sectors(q, USE_MAX_SECTORS);
#endif
#ifdef USE_MAX_PHYS_SEGMENTS
blk_queue_max_phys_segments(q, USE_MAX_PHYS_SEGMENTS);
#endif
#ifdef USE_MAX_HW_SEGMENTS
blk_queue_max_hw_segments(q, USE_MAX_HW_SEGMENTS);
#endif
#ifdef USE_MAX_SEGMENT_SIZE
blk_queue_max_segment_size(q, USE_MAX_SEGMENT_SIZE);
#endif
#ifdef USE_LOGICAL_BLOCK_SIZE
blk_queue_logical_block_size(q, USE_LOGICAL_BLOCK_SIZE);
#endif
#ifdef USE_SEGMENT_BOUNDARY
blk_queue_segment_boundary(q, USE_SEGMENT_BOUNDARY);
#endif
#ifdef USE_QUEUE_ORDERED
blk_queue_ordered(q, USE_QUEUE_ORDERED, NULL);
#endif
blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
q->unplug_fn = if_unplug;
q->queue_lock = &input->req_lock; // needed!
input->bdev = bdget(MKDEV(disk->major, minor));
/* we have no partitions. we contain only ourselves. */
input->bdev->bd_contains = input->bdev;
MARS_INF("ra_pages OLD = %lu NEW = %d\n", q->backing_dev_info.ra_pages, brick->readahead);
q->backing_dev_info.ra_pages = brick->readahead;
#ifdef USE_CONGESTED_FN
q->backing_dev_info.congested_fn = mars_congested;
q->backing_dev_info.congested_data = input;
#endif
#ifdef USE_MERGE_BVEC
blk_queue_merge_bvec(q, mars_merge_bvec);
#endif
// point of no return
add_disk(disk);
input->disk = disk;
//set_device_ro(input->bdev, 0); // TODO: implement modes
mars_power_led_on((void*)brick, true);
} else {
mars_power_led_on((void*)brick, false);
disk = input->disk;
if (!disk)
goto is_down;
#if 0
q = disk->queue;
if (q) {
blk_cleanup_queue(q);
input->q = NULL;
}
#endif
if (atomic_read(&input->open_count) > 0) {
MARS_INF("device '%s' is open %d times, cannot shutdown\n", disk->disk_name, atomic_read(&input->open_count));
return -EBUSY;
}
if (input->bdev) {
bdput(input->bdev);
input->bdev = NULL;
}
del_gendisk(input->disk);
put_disk(input->disk);
input->disk = NULL;
is_down:
mars_power_led_off((void*)brick, true);
}
return 0;
}
//////////////// informational / statistics ///////////////
static
char *if_statistics(struct if_brick *brick, int verbose)
{
struct if_input *input = brick->inputs[0];
char *res = kmalloc(512, GFP_MARS);
int tmp1 = atomic_read(&input->total_read_count);
int tmp2 = atomic_read(&input->total_mref_read_count);
int tmp3 = atomic_read(&input->total_write_count);
int tmp4 = atomic_read(&input->total_mref_write_count);
if (!res)
return NULL;
sprintf(res, "total reads = %d mref_reads = %d (%d%%) writes = %d mref_writes = %d (%d%%) empty = %d | plugged = %d flying = %d (reads = %d writes = %d)\n",
tmp1,
tmp2,
tmp1 ? tmp2 * 100 / tmp1 : 0,
tmp3,
tmp4,
tmp3 ? tmp4 * 100 / tmp3 : 0,
atomic_read(&input->total_empty_count),
atomic_read(&input->plugged_count),
atomic_read(&input->flying_count),
atomic_read(&input->read_flying_count),
atomic_read(&input->write_flying_count));
return res;
}
static
void if_reset_statistics(struct if_brick *brick)
{
struct if_input *input = brick->inputs[0];
atomic_set(&input->total_read_count, 0);
atomic_set(&input->total_write_count, 0);
atomic_set(&input->total_empty_count, 0);
atomic_set(&input->total_mref_read_count, 0);
atomic_set(&input->total_mref_write_count, 0);
}
////////////////// own brick / input / output operations //////////////////
// none
//////////////// object / aspect constructors / destructors ///////////////
static int if_mref_aspect_init_fn(struct generic_aspect *_ini, void *_init_data)
{
struct if_mref_aspect *ini = (void*)_ini;
INIT_LIST_HEAD(&ini->plug_head);
INIT_LIST_HEAD(&ini->hash_head);
return 0;
}
static void if_mref_aspect_exit_fn(struct generic_aspect *_ini, void *_init_data)
{
struct if_mref_aspect *ini = (void*)_ini;
CHECK_HEAD_EMPTY(&ini->plug_head);
CHECK_HEAD_EMPTY(&ini->hash_head);
}
MARS_MAKE_STATICS(if);
//////////////////////// constructors / destructors ////////////////////////
static int if_brick_construct(struct if_brick *brick)
{
struct if_output *hidden = &brick->hidden_output;
_if_output_init(brick, hidden, "internal");
return 0;
}
static int if_brick_destruct(struct if_brick *brick)
{
return 0;
}
static int if_input_construct(struct if_input *input)
{
int i;
for (i = 0; i < IF_HASH_MAX; i++) {
spin_lock_init(&input->hash_lock[i]);
INIT_LIST_HEAD(&input->hash_table[i]);
}
INIT_LIST_HEAD(&input->plug_anchor);
sema_init(&input->kick_sem, 1);
spin_lock_init(&input->req_lock);
atomic_set(&input->open_count, 0);
atomic_set(&input->flying_count, 0);
atomic_set(&input->plugged_count, 0);
#ifdef USE_TIMER
init_timer(&input->timer);
#endif
return 0;
}
static int if_input_destruct(struct if_input *input)
{
return 0;
}
static int if_output_construct(struct if_output *output)
{
return 0;
}
///////////////////////// static structs ////////////////////////
static struct if_brick_ops if_brick_ops = {
.brick_switch = if_switch,
.brick_statistics = if_statistics,
.reset_statistics = if_reset_statistics,
};
static struct if_output_ops if_output_ops = {
.make_object_layout = if_make_object_layout,
};
const struct if_input_type if_input_type = {
.type_name = "if_input",
.input_size = sizeof(struct if_input),
.input_construct = &if_input_construct,
.input_destruct = &if_input_destruct,
};
static const struct if_input_type *if_input_types[] = {
&if_input_type,
};
const struct if_output_type if_output_type = {
.type_name = "if_output",
.output_size = sizeof(struct if_output),
.master_ops = &if_output_ops,
.output_construct = &if_output_construct,
.aspect_types = if_aspect_types,
.layout_code = {
[BRICK_OBJ_MREF] = LAYOUT_ALL,
}
};
static const struct if_output_type *if_output_types[] = {
&if_output_type,
};
const struct if_brick_type if_brick_type = {
.type_name = "if_brick",
.brick_size = sizeof(struct if_brick),
.max_inputs = 1,
.max_outputs = 0,
.master_ops = &if_brick_ops,
.default_input_types = if_input_types,
.default_output_types = if_output_types,
.brick_construct = &if_brick_construct,
.brick_destruct = &if_brick_destruct,
};
EXPORT_SYMBOL_GPL(if_brick_type);
////////////////// module init stuff /////////////////////////
static void __exit exit_if(void)
{
int status;
MARS_INF("exit_if()\n");
status = if_unregister_brick_type();
unregister_blkdev(MARS_MAJOR, "mars");
}
static int __init init_if(void)
{
int status;
(void)if_aspect_types; // not used, shut up gcc
MARS_INF("init_if()\n");
status = register_blkdev(MARS_MAJOR, "mars");
if (status)
return status;
status = if_register_brick_type();
if (status)
goto err_device;
return status;
err_device:
MARS_ERR("init_if() status=%d\n", status);
exit_if();
return status;
}
MODULE_DESCRIPTION("MARS if");
MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
MODULE_LICENSE("GPL");
module_init(init_if);
module_exit(exit_if);