mars/mars_bio.c
Thomas Schoebel-Theuer 3091f75f67 import mars-125.tgz
2013-01-08 15:54:44 +01:00

687 lines
16 KiB
C

// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
// Bio brick (interface to blkdev IO via kernel bios)
//#define BRICK_DEBUGGING
//#define MARS_DEBUGGING
//#define IO_DEBUGGING
//#define FAKE_IO
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/bio.h>
#include <linux/kthread.h>
#include "mars.h"
///////////////////////// own type definitions ////////////////////////
#include "mars_bio.h"
static void bio_ref_put(struct bio_output *output, struct mref_object *mref);
///////////////////////// own helper functions ////////////////////////
/* This is called from the kernel bio layer.
*/
static
void bio_callback(struct bio *bio, int code)
{
struct bio_mref_aspect *mref_a = bio->bi_private;
struct bio_brick *brick;
unsigned long flags;
CHECK_PTR(mref_a, err);
CHECK_PTR(mref_a->output, err);
brick = mref_a->output->brick;
CHECK_PTR(brick, err);
mref_a->status_code = code;
spin_lock_irqsave(&brick->lock, flags);
if (list_empty(&mref_a->io_head)) {
list_add_tail(&mref_a->io_head, &brick->completed_list);
atomic_inc(&brick->completed_count);
}
spin_unlock_irqrestore(&brick->lock, flags);
wake_up_interruptible(&brick->event);
return;
err:
MARS_FAT("cannot handle bio callback\n");
}
/* Map from kernel address/length to struct page (if not already known),
* check alignment constraints, create bio from it.
* Return the length (may be smaller than requested).
*/
static
int make_bio(struct bio_brick *brick, void *data, int len, loff_t pos, struct bio_mref_aspect *private, struct bio **_bio)
{
unsigned long long sector;
int sector_offset;
int data_offset;
int page_offset;
int page_len;
int bvec_count;
int rest_len = len;
int result_len = 0;
int status;
int i;
struct bio *bio = NULL;
struct block_device *bdev;
status = -EINVAL;
CHECK_PTR(brick, out);
bdev = brick->bdev;
CHECK_PTR(bdev, out);
if (unlikely(rest_len <= 0)) {
MARS_ERR("bad bio len %d\n", rest_len);
goto out;
}
sector = pos >> 9; // TODO: make dynamic
sector_offset = pos & ((1 << 9) - 1); // TODO: make dynamic
data_offset = ((unsigned long)data) & ((1 << 9) - 1); // TODO: make dynamic
if (unlikely(sector_offset > 0)) {
MARS_ERR("odd sector offset %d\n", sector_offset);
goto out;
}
if (unlikely(sector_offset != data_offset)) {
MARS_ERR("bad alignment: sector_offset %d != data_offet %d\n", sector_offset, data_offset);
goto out;
}
if (unlikely(rest_len & ((1 << 9) - 1))) {
MARS_ERR("odd length %d\n", rest_len);
goto out;
}
page_offset = ((unsigned long)data) & (PAGE_SIZE-1);
page_len = rest_len + page_offset;
bvec_count = (page_len - 1) / PAGE_SIZE + 1;
if (bvec_count > brick->bvec_max) {
bvec_count = brick->bvec_max;
}
MARS_IO("sector_offset = %d data = %p pos = %lld rest_len = %d page_offset = %d page_len = %d bvec_count = %d\n", sector_offset, data, pos, rest_len, page_offset, page_len, bvec_count);
bio = bio_alloc(GFP_MARS, bvec_count);
status = -ENOMEM;
if (unlikely(!bio)) {
goto out;
}
for (i = 0; i < bvec_count && rest_len > 0; i++) {
struct page *page;
int this_rest = PAGE_SIZE - page_offset;
int this_len = rest_len;
if (this_len > this_rest) {
this_len = this_rest;
}
#ifdef MARS_DEBUGGING
if (unlikely(!virt_addr_valid(data))) {
MARS_ERR("invalid virtual kernel address %p\n", data);
status = -EINVAL;
goto out;
}
#endif
page = brick_iomap(data, &page_offset, &this_len);
if (unlikely(!page)) {
MARS_ERR("cannot iomap() kernel address %p\n", data);
status = -EINVAL;
goto out;
}
MARS_IO(" i = %d page = %p bv_len = %d bv_offset = %d\n", i, page, this_len, page_offset);
bio->bi_io_vec[i].bv_page = page;
bio->bi_io_vec[i].bv_len = this_len;
bio->bi_io_vec[i].bv_offset = page_offset;
data += this_len;
rest_len -= this_len;
result_len += this_len;
page_offset = 0;
//MARS_IO("page_offset=%d this_len=%d (new len=%d, new status=%d)\n", page_offset, this_len, rest_len, status);
}
if (unlikely(rest_len != 0)) {
MARS_ERR("computation of bvec_count %d was wrong, diff=%d\n", bvec_count, rest_len);
status = -EIO;
goto out;
}
bio->bi_vcnt = i;
bio->bi_idx = 0;
bio->bi_size = result_len;
bio->bi_sector = sector;
bio->bi_bdev = bdev;
bio->bi_private = private;
bio->bi_end_io = bio_callback;
bio->bi_rw = 0; // must be filled in later
status = result_len;
out:
if (unlikely(status < 0)) {
MARS_ERR("error %d\n", status);
if (bio) {
bio_put(bio);
bio = NULL;
}
}
*_bio = bio;
return status;
}
////////////////// own brick / input / output operations //////////////////
static int bio_get_info(struct bio_output *output, struct mars_info *info)
{
struct bio_brick *brick = output->brick;
int status = 0;
info->current_size = brick->total_size;
MARS_DBG("determined device size = %lld\n", info->current_size);
info->backing_file = brick->filp;
if (!brick->filp) {
status = -ENOENT;
}
return status;
}
static int bio_ref_get(struct bio_output *output, struct mref_object *mref)
{
struct bio_mref_aspect *mref_a = bio_mref_get_aspect(output, mref);
int status = -EINVAL;
CHECK_PTR(mref_a, done);
CHECK_PTR(output->brick, done);
_CHECK_ATOMIC(&mref->ref_count, !=, 0);
if (mref_a->output)
goto ok;
mref_a->output = output;
mref_a->bio = NULL;
if (!mref->ref_data) { // buffered IO.
status = -ENOMEM;
mref->ref_data = brick_block_alloc(mref->ref_pos, (mref_a->alloc_len = mref->ref_len));
if (unlikely(!mref->ref_data)) {
goto done;
}
mref_a->do_dealloc = true;
}
status = make_bio(output->brick, mref->ref_data, mref->ref_len, mref->ref_pos, mref_a, &mref_a->bio);
if (unlikely(status < 0 || !mref_a->bio)) {
MARS_ERR("could not create bio, status = %d\n", status);
goto done;
}
MARS_IO("len %d -> %d fly = %d\n", mref->ref_len, status, atomic_read(&output->brick->fly_count));
mref->ref_len = status;
ok:
atomic_inc(&mref->ref_count);
status = 0;
done:
return status;
}
static
void bio_ref_put(struct bio_output *output, struct mref_object *mref)
{
struct bio_mref_aspect *mref_a;
CHECK_ATOMIC(&mref->ref_count, 1);
if (!atomic_dec_and_test(&mref->ref_count)) {
goto done;
}
MARS_IO("deallocating\n");
mref->ref_total_size = output->brick->total_size;
mref_a = bio_mref_get_aspect(output, mref);
CHECK_PTR(mref_a, err);
if (likely(mref_a->bio)) {
#ifdef MARS_DEBUGGING
int bi_cnt = atomic_read(&mref_a->bio->bi_cnt);
if (bi_cnt > 1) {
MARS_DBG("bi_cnt = %d\n", bi_cnt);
}
#endif
bio_put(mref_a->bio);
mref_a->bio = NULL;
}
if (mref_a->do_dealloc) {
MARS_IO("free page\n");
brick_block_free(mref->ref_data, mref_a->alloc_len);
mref->ref_data = NULL;
}
bio_free_mref(mref);
done:
return;
err:
MARS_FAT("cannot work\n");
}
static
void _bio_ref_io(struct bio_output *output, struct mref_object *mref)
{
struct bio_brick *brick = output->brick;
struct bio_mref_aspect *mref_a = bio_mref_get_aspect(output, mref);
struct bio *bio;
struct generic_callback *cb;
int rw;
int status = -EINVAL;
CHECK_PTR(mref_a, err);
bio = mref_a->bio;
CHECK_PTR(bio, err);
CHECK_ATOMIC(&mref->ref_count, 1);
atomic_inc(&mref->ref_count);
atomic_inc(&brick->fly_count);
bio_get(bio);
rw = mref->ref_rw & 1;
if (brick->do_noidle) {
rw |= (1 << BIO_RW_NOIDLE);
}
if (!mref->ref_skip_sync) {
if (brick->do_sync) {
rw |= (1 << BIO_RW_SYNCIO);
}
if (brick->do_unplug) {
rw |= (1 << BIO_RW_UNPLUG);
}
}
MARS_IO("starting IO rw = %d fly = %d\n", rw, atomic_read(&brick->fly_count));
mars_trace(mref, "bio_submit");
#ifdef FAKE_IO
bio->bi_end_io(bio, 0);
#else
bio->bi_rw = rw;
submit_bio(rw, bio);
#endif
status = 0;
if (unlikely(bio_flagged(bio, BIO_EOPNOTSUPP)))
status = -EOPNOTSUPP;
MARS_IO("submitted\n");
if (likely(status >= 0))
goto done;
bio_put(bio);
atomic_dec(&brick->fly_count);
err:
MARS_ERR("IO error %d\n", status);
cb = mref->ref_cb;
if (cb) {
cb->cb_error = status;
cb->cb_fn(cb);
}
done: ;
}
static
void bio_ref_io(struct bio_output *output, struct mref_object *mref)
{
if (mref->ref_prio == MARS_PRIO_LOW) { // queue for background IO
struct bio_mref_aspect *mref_a = bio_mref_get_aspect(output, mref);
struct bio_brick *brick = output->brick;
unsigned long flags;
spin_lock_irqsave(&brick->lock, flags);
list_add_tail(&mref_a->io_head, &brick->background_list);
spin_unlock_irqrestore(&brick->lock, flags);
atomic_inc(&brick->background_count);
atomic_inc(&brick->total_background_count);
wake_up_interruptible(&brick->event);
return;
}
// foreground IO: start immediately
_bio_ref_io(output, mref);
}
static int bio_thread(void *data)
{
struct bio_brick *brick = data;
MARS_INF("bio kthread has started on '%s'.\n", brick->brick_name);
for (;;) {
LIST_HEAD(tmp_list);
unsigned long flags;
wait_event_interruptible_timeout(
brick->event,
atomic_read(&brick->completed_count) > 0 ||
(atomic_read(&brick->background_count) > 0 && !atomic_read(&brick->fly_count)),
12 * HZ);
spin_lock_irqsave(&brick->lock, flags);
list_replace_init(&brick->completed_list, &tmp_list);
spin_unlock_irqrestore(&brick->lock, flags);
for (;;) {
struct list_head *tmp;
struct bio_mref_aspect *mref_a;
struct mref_object *mref;
struct generic_callback *cb;
int code;
if (list_empty(&tmp_list)) {
if (kthread_should_stop())
goto done;
break;
}
tmp = tmp_list.next;
list_del_init(tmp);
atomic_dec(&brick->completed_count);
mref_a = container_of(tmp, struct bio_mref_aspect, io_head);
code = mref_a->status_code;
MARS_IO("completed , status = %d\n", code);
mref = mref_a->object;
mars_trace(mref, "bio_endio");
cb = mref->ref_cb;
cb->cb_error = code;
if (code < 0) {
MARS_ERR("IO error %d\n", code);
} else {
mref->ref_flags |= MREF_UPTODATE;
}
cb->cb_fn(cb);
atomic_dec(&brick->fly_count);
atomic_inc(&brick->total_completed_count);
MARS_IO("fly = %d\n", atomic_read(&brick->fly_count));
if (likely(mref_a->bio)) {
bio_put(mref_a->bio);
}
bio_ref_put(mref_a->output, mref);
}
if (!atomic_read(&brick->fly_count) && atomic_read(&brick->background_count) > 0) {
struct list_head *tmp;
struct bio_mref_aspect *mref_a;
struct mref_object *mref;
atomic_dec(&brick->background_count);
spin_lock_irqsave(&brick->lock, flags);
tmp = brick->background_list.next;
list_del_init(tmp);
spin_unlock_irqrestore(&brick->lock, flags);
mref_a = container_of(tmp, struct bio_mref_aspect, io_head);
mref = mref_a->object;
if (unlikely(!mref)) {
MARS_ERR("invalid mref\n");
continue;
}
_bio_ref_io(mref_a->output, mref);
}
}
done:
MARS_INF("bio kthread has stopped.\n");
return 0;
}
static int bio_switch(struct bio_brick *brick)
{
int status = 0;
if (brick->power.button) {
mars_power_led_off((void*)brick, false);
if (!brick->bdev) {
static int index = 0;
const char *path = brick->brick_name;
int flags = O_RDWR | O_LARGEFILE;
int prot = 0600;
struct inode *inode;
struct request_queue *q;
mm_segment_t oldfs;
oldfs = get_fs();
set_fs(get_ds());
brick->filp = filp_open(path, flags, prot);
set_fs(oldfs);
if (!brick->filp) {
MARS_ERR("cannot open '%s'\n", path);
status = -ENOENT;
goto done;
}
status = -EINVAL;
CHECK_PTR(brick->filp->f_mapping, done);
inode = brick->filp->f_mapping->host;
CHECK_PTR(inode, done);
if (!S_ISBLK(inode->i_mode)) {
MARS_ERR("sorry, '%s' is not a block device\n", path);
goto done;
}
q = bdev_get_queue(inode->i_bdev);
CHECK_PTR(q, done);
#if 1
MARS_INF("ra_pages OLD=%lu NEW=%d\n", q->backing_dev_info.ra_pages, brick->ra_pages);
q->backing_dev_info.ra_pages = brick->ra_pages;
#endif
brick->bvec_max = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
brick->total_size = inode->i_size;
brick->thread = kthread_create(bio_thread, brick, "mars_bio%d", index++);
if (IS_ERR(brick->thread)) {
status = PTR_ERR(brick->thread);
MARS_ERR("cannot create thread\n");
brick->thread = NULL;
}
if (brick->thread) {
brick->bdev = inode->i_bdev;
wake_up_process(brick->thread);
status = 0;
}
}
if (brick->bdev) {
mars_power_led_on((void*)brick, true);
}
} else {
mars_power_led_on((void*)brick, false);
// TODO: wait for IO completion
if (brick->filp) {
filp_close(brick->filp, NULL);
brick->filp = NULL;
}
if (brick->thread) {
MARS_INF("stopping thread...\n");
kthread_stop(brick->thread);
brick->thread = NULL;
}
brick->bdev = NULL;
brick->total_size = 0;
mars_power_led_off((void*)brick, true);
}
done:
if (status < 0 && brick->filp) {
filp_close(brick->filp, NULL);
brick->filp = NULL;
}
return status;
}
//////////////// informational / statistics ///////////////
static noinline
char *bio_statistics(struct bio_brick *brick, int verbose)
{
char *res = brick_string_alloc(0);
if (!res)
return NULL;
// FIXME: check for allocation overflows
snprintf(res, 512, "total completed = %d background = %d | flying = %d completing = %d background = %d\n", atomic_read(&brick->total_completed_count), atomic_read(&brick->total_background_count), atomic_read(&brick->fly_count), atomic_read(&brick->completed_count), atomic_read(&brick->background_count));
return res;
}
static noinline
void bio_reset_statistics(struct bio_brick *brick)
{
atomic_set(&brick->total_completed_count, 0);
atomic_set(&brick->total_background_count, 0);
}
//////////////// object / aspect constructors / destructors ///////////////
static int bio_mref_aspect_init_fn(struct generic_aspect *_ini, void *_init_data)
{
struct bio_mref_aspect *ini = (void*)_ini;
INIT_LIST_HEAD(&ini->io_head);
return 0;
}
static void bio_mref_aspect_exit_fn(struct generic_aspect *_ini, void *_init_data)
{
struct bio_mref_aspect *ini = (void*)_ini;
(void)ini;
}
MARS_MAKE_STATICS(bio);
////////////////////// brick constructors / destructors ////////////////////
static int bio_brick_construct(struct bio_brick *brick)
{
spin_lock_init(&brick->lock);
INIT_LIST_HEAD(&brick->background_list);
INIT_LIST_HEAD(&brick->completed_list);
init_waitqueue_head(&brick->event);
return 0;
}
static int bio_brick_destruct(struct bio_brick *brick)
{
return 0;
}
static int bio_output_construct(struct bio_output *output)
{
return 0;
}
static int bio_output_destruct(struct bio_output *output)
{
return 0;
}
///////////////////////// static structs ////////////////////////
static struct bio_brick_ops bio_brick_ops = {
.brick_switch = bio_switch,
.brick_statistics = bio_statistics,
.reset_statistics = bio_reset_statistics,
};
static struct bio_output_ops bio_output_ops = {
.make_object_layout = bio_make_object_layout,
.mars_get_info = bio_get_info,
.mref_get = bio_ref_get,
.mref_put = bio_ref_put,
.mref_io = bio_ref_io,
};
const struct bio_input_type bio_input_type = {
.type_name = "bio_input",
.input_size = sizeof(struct bio_input),
};
static const struct bio_input_type *bio_input_types[] = {
&bio_input_type,
};
const struct bio_output_type bio_output_type = {
.type_name = "bio_output",
.output_size = sizeof(struct bio_output),
.master_ops = &bio_output_ops,
.output_construct = &bio_output_construct,
.output_destruct = &bio_output_destruct,
.aspect_types = bio_aspect_types,
.layout_code = {
[BRICK_OBJ_MREF] = LAYOUT_ALL,
}
};
static const struct bio_output_type *bio_output_types[] = {
&bio_output_type,
};
const struct bio_brick_type bio_brick_type = {
.type_name = "bio_brick",
.brick_size = sizeof(struct bio_brick),
.max_inputs = 0,
.max_outputs = 1,
.master_ops = &bio_brick_ops,
.default_input_types = bio_input_types,
.default_output_types = bio_output_types,
.brick_construct = &bio_brick_construct,
.brick_destruct = &bio_brick_destruct,
};
EXPORT_SYMBOL_GPL(bio_brick_type);
////////////////// module init stuff /////////////////////////
int __init init_mars_bio(void)
{
MARS_INF("init_bio()\n");
_bio_brick_type = (void*)&bio_brick_type;
return bio_register_brick_type();
}
void __exit exit_mars_bio(void)
{
MARS_INF("exit_bio()\n");
bio_unregister_brick_type();
}
#ifndef CONFIG_MARS_HAVE_BIGMODULE
MODULE_DESCRIPTION("MARS bio brick");
MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
MODULE_LICENSE("GPL");
module_init(init_mars_bio);
module_exit(exit_mars_bio);
#endif