linux/drivers/md/bcache/io.c
Kent Overstreet 749b61dab3 bcache: remove driver private bio splitting code
The bcache driver has always accepted arbitrarily large bios and split
them internally.  Now that every driver must accept arbitrarily large
bios this code isn't nessecary anymore.

Cc: linux-bcache@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-13 12:31:40 -06:00

146 lines
3.4 KiB
C

/*
* Some low level IO code, and hacks for various block layer limitations
*
* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
* Copyright 2012 Google, Inc.
*/
#include "bcache.h"
#include "bset.h"
#include "debug.h"
#include <linux/blkdev.h>
/* Bios with headers */
void bch_bbio_free(struct bio *bio, struct cache_set *c)
{
struct bbio *b = container_of(bio, struct bbio, bio);
mempool_free(b, c->bio_meta);
}
struct bio *bch_bbio_alloc(struct cache_set *c)
{
struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO);
struct bio *bio = &b->bio;
bio_init(bio);
bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
bio->bi_max_vecs = bucket_pages(c);
bio->bi_io_vec = bio->bi_inline_vecs;
return bio;
}
void __bch_submit_bbio(struct bio *bio, struct cache_set *c)
{
struct bbio *b = container_of(bio, struct bbio, bio);
bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0);
bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev;
b->submit_time_us = local_clock_us();
closure_bio_submit(bio, bio->bi_private);
}
void bch_submit_bbio(struct bio *bio, struct cache_set *c,
struct bkey *k, unsigned ptr)
{
struct bbio *b = container_of(bio, struct bbio, bio);
bch_bkey_copy_single_ptr(&b->key, k, ptr);
__bch_submit_bbio(bio, c);
}
/* IO errors */
void bch_count_io_errors(struct cache *ca, int error, const char *m)
{
/*
* The halflife of an error is:
* log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
*/
if (ca->set->error_decay) {
unsigned count = atomic_inc_return(&ca->io_count);
while (count > ca->set->error_decay) {
unsigned errors;
unsigned old = count;
unsigned new = count - ca->set->error_decay;
/*
* First we subtract refresh from count; each time we
* succesfully do so, we rescale the errors once:
*/
count = atomic_cmpxchg(&ca->io_count, old, new);
if (count == old) {
count = new;
errors = atomic_read(&ca->io_errors);
do {
old = errors;
new = ((uint64_t) errors * 127) / 128;
errors = atomic_cmpxchg(&ca->io_errors,
old, new);
} while (old != errors);
}
}
}
if (error) {
char buf[BDEVNAME_SIZE];
unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT,
&ca->io_errors);
errors >>= IO_ERROR_SHIFT;
if (errors < ca->set->error_limit)
pr_err("%s: IO error on %s, recovering",
bdevname(ca->bdev, buf), m);
else
bch_cache_set_error(ca->set,
"%s: too many IO errors %s",
bdevname(ca->bdev, buf), m);
}
}
void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio,
int error, const char *m)
{
struct bbio *b = container_of(bio, struct bbio, bio);
struct cache *ca = PTR_CACHE(c, &b->key, 0);
unsigned threshold = bio->bi_rw & REQ_WRITE
? c->congested_write_threshold_us
: c->congested_read_threshold_us;
if (threshold) {
unsigned t = local_clock_us();
int us = t - b->submit_time_us;
int congested = atomic_read(&c->congested);
if (us > (int) threshold) {
int ms = us / 1024;
c->congested_last_us = t;
ms = min(ms, CONGESTED_MAX + congested);
atomic_sub(ms, &c->congested);
} else if (congested < 0)
atomic_inc(&c->congested);
}
bch_count_io_errors(ca, error, m);
}
void bch_bbio_endio(struct cache_set *c, struct bio *bio,
int error, const char *m)
{
struct closure *cl = bio->bi_private;
bch_bbio_count_io_errors(c, bio, error, m);
bio_put(bio);
closure_put(cl);
}