[deliverable/linux.git] / drivers / md / bcache / io.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>

static void bch_bi_idx_hack_endio(struct bio *bio, int error)
{
	struct bio *p = bio->bi_private;

	bio_endio(p, error);
	bio_put(bio);
}

static void bch_generic_make_request_hack(struct bio *bio)
{
	if (bio->bi_idx) {
		struct bio *clone = bio_alloc(GFP_NOIO, bio_segments(bio));

		memcpy(clone->bi_io_vec,
		       bio_iovec(bio),
		       bio_segments(bio) * sizeof(struct bio_vec));

		clone->bi_sector	= bio->bi_sector;
		clone->bi_bdev		= bio->bi_bdev;
		clone->bi_rw		= bio->bi_rw;
		clone->bi_vcnt		= bio_segments(bio);
		clone->bi_size		= bio->bi_size;

		clone->bi_private	= bio;
		clone->bi_end_io	= bch_bi_idx_hack_endio;

		bio = clone;
	}

	/*
	 * Hack, since drivers that clone bios clone up to bi_max_vecs, but our
	 * bios might have had more than that (before we split them per device
	 * limitations).
	 *
	 * To be taken out once immutable bvec stuff is in.
	 */
	bio->bi_max_vecs = bio->bi_vcnt;

	generic_make_request(bio);
}

/**
 * bch_bio_split - split a bio
 * @bio:	bio to split
 * @sectors:	number of sectors to split from the front of @bio
 * @gfp:	gfp mask
 * @bs:		bio set to allocate from
 *
 * Allocates and returns a new bio which represents @sectors from the start of
 * @bio, and updates @bio to represent the remaining sectors.
 *
 * If bio_sectors(@bio) was less than or equal to @sectors, returns @bio
 * unchanged.
 *
 * The newly allocated bio will point to @bio's bi_io_vec, if the split was on a
 * bvec boundry; it is the caller's responsibility to ensure that @bio is not
 * freed before the split.
 */
struct bio *bch_bio_split(struct bio *bio, int sectors,
			  gfp_t gfp, struct bio_set *bs)
{
	unsigned idx = bio->bi_idx, vcnt = 0, nbytes = sectors << 9;
	struct bio_vec *bv;
	struct bio *ret = NULL;

	BUG_ON(sectors <= 0);

	if (sectors >= bio_sectors(bio))
		return bio;

	if (bio->bi_rw & REQ_DISCARD) {
		ret = bio_alloc_bioset(gfp, 1, bs);
		if (!ret)
			return NULL;
		idx = 0;
		goto out;
	}

	bio_for_each_segment(bv, bio, idx) {
		vcnt = idx - bio->bi_idx;

		if (!nbytes) {
			ret = bio_alloc_bioset(gfp, vcnt, bs);
			if (!ret)
				return NULL;

			memcpy(ret->bi_io_vec, bio_iovec(bio),
			       sizeof(struct bio_vec) * vcnt);

			break;
		} else if (nbytes < bv->bv_len) {
			ret = bio_alloc_bioset(gfp, ++vcnt, bs);
			if (!ret)
				return NULL;

			memcpy(ret->bi_io_vec, bio_iovec(bio),
			       sizeof(struct bio_vec) * vcnt);

			ret->bi_io_vec[vcnt - 1].bv_len = nbytes;
			bv->bv_offset	+= nbytes;
			bv->bv_len	-= nbytes;
			break;
		}

		nbytes -= bv->bv_len;
	}
out:
	ret->bi_bdev	= bio->bi_bdev;
	ret->bi_sector	= bio->bi_sector;
	ret->bi_size	= sectors << 9;
	ret->bi_rw	= bio->bi_rw;
	ret->bi_vcnt	= vcnt;
	ret->bi_max_vecs = vcnt;

	bio->bi_sector	+= sectors;
	bio->bi_size	-= sectors << 9;
	bio->bi_idx	 = idx;

	if (bio_integrity(bio)) {
		if (bio_integrity_clone(ret, bio, gfp)) {
			bio_put(ret);
			return NULL;
		}

		bio_integrity_trim(ret, 0, bio_sectors(ret));
		bio_integrity_trim(bio, bio_sectors(ret), bio_sectors(bio));
	}

	return ret;
}

static unsigned bch_bio_max_sectors(struct bio *bio)
{
	unsigned ret = bio_sectors(bio);
	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
	unsigned max_segments = min_t(unsigned, BIO_MAX_PAGES,
				      queue_max_segments(q));

	if (bio->bi_rw & REQ_DISCARD)
		return min(ret, q->limits.max_discard_sectors);

	if (bio_segments(bio) > max_segments ||
	    q->merge_bvec_fn) {
		struct bio_vec *bv;
		int i, seg = 0;

		ret = 0;

		bio_for_each_segment(bv, bio, i) {
			struct bvec_merge_data bvm = {
				.bi_bdev	= bio->bi_bdev,
				.bi_sector	= bio->bi_sector,
				.bi_size	= ret << 9,
				.bi_rw		= bio->bi_rw,
			};

			if (seg == max_segments)
				break;

			if (q->merge_bvec_fn &&
			    q->merge_bvec_fn(q, &bvm, bv) < (int) bv->bv_len)
				break;

			seg++;
			ret += bv->bv_len >> 9;
		}
	}

	ret = min(ret, queue_max_sectors(q));

	WARN_ON(!ret);
	ret = max_t(int, ret, bio_iovec(bio)->bv_len >> 9);

	return ret;
}

static void bch_bio_submit_split_done(struct closure *cl)
{
	struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);

	s->bio->bi_end_io = s->bi_end_io;
	s->bio->bi_private = s->bi_private;
	bio_endio(s->bio, 0);

	closure_debug_destroy(&s->cl);
	mempool_free(s, s->p->bio_split_hook);
}

static void bch_bio_submit_split_endio(struct bio *bio, int error)
{
	struct closure *cl = bio->bi_private;
	struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);

	if (error)
		clear_bit(BIO_UPTODATE, &s->bio->bi_flags);

	bio_put(bio);
	closure_put(cl);
}

void bch_generic_make_request(struct bio *bio, struct bio_split_pool *p)
{
	struct bio_split_hook *s;
	struct bio *n;

	if (!bio_has_data(bio) && !(bio->bi_rw & REQ_DISCARD))
		goto submit;

	if (bio_sectors(bio) <= bch_bio_max_sectors(bio))
		goto submit;

	s = mempool_alloc(p->bio_split_hook, GFP_NOIO);
	closure_init(&s->cl, NULL);

	s->bio		= bio;
	s->p		= p;
	s->bi_end_io	= bio->bi_end_io;
	s->bi_private	= bio->bi_private;
	bio_get(bio);

	do {
		n = bch_bio_split(bio, bch_bio_max_sectors(bio),
				  GFP_NOIO, s->p->bio_split);

		n->bi_end_io	= bch_bio_submit_split_endio;
		n->bi_private	= &s->cl;

		closure_get(&s->cl);
		bch_generic_make_request_hack(n);
	} while (n != bio);

	continue_at(&s->cl, bch_bio_submit_split_done, NULL);
submit:
	bch_generic_make_request_hack(bio);
}

/* 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_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, PTR_CACHE(c, &b->key, 0));
}

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);
}
Commit	Line	Data
cafe5635 KO	1	/*
	2	* Some low level IO code, and hacks for various block layer limitations
	3	*
	4	* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
	5	* Copyright 2012 Google, Inc.
	6	*/
	7
	8	#include "bcache.h"
	9	#include "bset.h"
	10	#include "debug.h"
	11
c37511b8 KO	12	#include <linux/blkdev.h>
c37511b8 KO	13
cafe5635 KO	14	static void bch_bi_idx_hack_endio(struct bio *bio, int error)
	15	{
	16	struct bio *p = bio->bi_private;
	17
	18	bio_endio(p, error);
	19	bio_put(bio);
	20	}
	21
	22	static void bch_generic_make_request_hack(struct bio *bio)
	23	{
	24	if (bio->bi_idx) {
	25	struct bio *clone = bio_alloc(GFP_NOIO, bio_segments(bio));
	26
	27	memcpy(clone->bi_io_vec,
	28	bio_iovec(bio),
	29	bio_segments(bio) * sizeof(struct bio_vec));
	30
	31	clone->bi_sector = bio->bi_sector;
	32	clone->bi_bdev = bio->bi_bdev;
	33	clone->bi_rw = bio->bi_rw;
	34	clone->bi_vcnt = bio_segments(bio);
	35	clone->bi_size = bio->bi_size;
	36
	37	clone->bi_private = bio;
	38	clone->bi_end_io = bch_bi_idx_hack_endio;
	39
	40	bio = clone;
	41	}
	42
bca97ada KO	43	/*
	44	* Hack, since drivers that clone bios clone up to bi_max_vecs, but our
	45	* bios might have had more than that (before we split them per device
	46	* limitations).
	47	*
	48	* To be taken out once immutable bvec stuff is in.
	49	*/
	50	bio->bi_max_vecs = bio->bi_vcnt;
	51
cafe5635 KO	52	generic_make_request(bio);
	53	}
	54
	55	/**
	56	* bch_bio_split - split a bio
	57	* @bio: bio to split
	58	* @sectors: number of sectors to split from the front of @bio
	59	* @gfp: gfp mask
	60	* @bs: bio set to allocate from
	61	*
	62	* Allocates and returns a new bio which represents @sectors from the start of
	63	* @bio, and updates @bio to represent the remaining sectors.
	64	*
	65	* If bio_sectors(@bio) was less than or equal to @sectors, returns @bio
	66	* unchanged.
	67	*
	68	* The newly allocated bio will point to @bio's bi_io_vec, if the split was on a
	69	* bvec boundry; it is the caller's responsibility to ensure that @bio is not
	70	* freed before the split.
cafe5635 KO	71	*/
	72	struct bio bch_bio_split(struct bio bio, int sectors,
	73	gfp_t gfp, struct bio_set *bs)
	74	{
	75	unsigned idx = bio->bi_idx, vcnt = 0, nbytes = sectors << 9;
	76	struct bio_vec *bv;
	77	struct bio *ret = NULL;
	78
	79	BUG_ON(sectors <= 0);
	80
cafe5635 KO	81	if (sectors >= bio_sectors(bio))
	82	return bio;
	83
	84	if (bio->bi_rw & REQ_DISCARD) {
	85	ret = bio_alloc_bioset(gfp, 1, bs);
5c694129 KAM	86	if (!ret)
5c694129 KAM	87	return NULL;
cafe5635 KO	88	idx = 0;
	89	goto out;
	90	}
	91
	92	bio_for_each_segment(bv, bio, idx) {
	93	vcnt = idx - bio->bi_idx;
	94
	95	if (!nbytes) {
	96	ret = bio_alloc_bioset(gfp, vcnt, bs);
	97	if (!ret)
	98	return NULL;
	99
	100	memcpy(ret->bi_io_vec, bio_iovec(bio),
	101	sizeof(struct bio_vec) * vcnt);
	102
	103	break;
	104	} else if (nbytes < bv->bv_len) {
	105	ret = bio_alloc_bioset(gfp, ++vcnt, bs);
	106	if (!ret)
	107	return NULL;
	108
	109	memcpy(ret->bi_io_vec, bio_iovec(bio),
	110	sizeof(struct bio_vec) * vcnt);
	111
	112	ret->bi_io_vec[vcnt - 1].bv_len = nbytes;
	113	bv->bv_offset += nbytes;
	114	bv->bv_len -= nbytes;
	115	break;
	116	}
	117
	118	nbytes -= bv->bv_len;
	119	}
	120	out:
	121	ret->bi_bdev = bio->bi_bdev;
	122	ret->bi_sector = bio->bi_sector;
	123	ret->bi_size = sectors << 9;
	124	ret->bi_rw = bio->bi_rw;
	125	ret->bi_vcnt = vcnt;
	126	ret->bi_max_vecs = vcnt;
	127
	128	bio->bi_sector += sectors;
	129	bio->bi_size -= sectors << 9;
	130	bio->bi_idx = idx;
	131
	132	if (bio_integrity(bio)) {
	133	if (bio_integrity_clone(ret, bio, gfp)) {
	134	bio_put(ret);
	135	return NULL;
	136	}
	137
	138	bio_integrity_trim(ret, 0, bio_sectors(ret));
	139	bio_integrity_trim(bio, bio_sectors(ret), bio_sectors(bio));
	140	}
	141
	142	return ret;
	143	}
	144
	145	static unsigned bch_bio_max_sectors(struct bio *bio)
	146	{
	147	unsigned ret = bio_sectors(bio);
	148	struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1545f137 KO	149	unsigned max_segments = min_t(unsigned, BIO_MAX_PAGES,
1545f137 KO	150	queue_max_segments(q));
cafe5635	151
cafe5635 KO	152	if (bio->bi_rw & REQ_DISCARD)
	153	return min(ret, q->limits.max_discard_sectors);
	154
1545f137	155	if (bio_segments(bio) > max_segments \|\|
cafe5635	156	q->merge_bvec_fn) {
8e51e414 KO	157	struct bio_vec *bv;
	158	int i, seg = 0;
	159
cafe5635 KO	160	ret = 0;
cafe5635 KO	161
8e51e414	162	bio_for_each_segment(bv, bio, i) {
a09ded8e KO	163	struct bvec_merge_data bvm = {
	164	.bi_bdev = bio->bi_bdev,
	165	.bi_sector = bio->bi_sector,
	166	.bi_size = ret << 9,
	167	.bi_rw = bio->bi_rw,
	168	};
	169
8e51e414 KO	170	if (seg == max_segments)
	171	break;
	172
cafe5635 KO	173	if (q->merge_bvec_fn &&
	174	q->merge_bvec_fn(q, &bvm, bv) < (int) bv->bv_len)
	175	break;
	176
8e51e414	177	seg++;
a09ded8e	178	ret += bv->bv_len >> 9;
cafe5635	179	}
cafe5635 KO	180	}
	181
	182	ret = min(ret, queue_max_sectors(q));
	183
	184	WARN_ON(!ret);
	185	ret = max_t(int, ret, bio_iovec(bio)->bv_len >> 9);
	186
	187	return ret;
	188	}
	189
	190	static void bch_bio_submit_split_done(struct closure *cl)
	191	{
	192	struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
	193
	194	s->bio->bi_end_io = s->bi_end_io;
	195	s->bio->bi_private = s->bi_private;
	196	bio_endio(s->bio, 0);
	197
	198	closure_debug_destroy(&s->cl);
	199	mempool_free(s, s->p->bio_split_hook);
	200	}
	201
	202	static void bch_bio_submit_split_endio(struct bio *bio, int error)
	203	{
	204	struct closure *cl = bio->bi_private;
	205	struct bio_split_hook *s = container_of(cl, struct bio_split_hook, cl);
	206
	207	if (error)
	208	clear_bit(BIO_UPTODATE, &s->bio->bi_flags);
	209
	210	bio_put(bio);
	211	closure_put(cl);
	212	}
	213
cafe5635 KO	214	void bch_generic_make_request(struct bio bio, struct bio_split_pool p)
	215	{
	216	struct bio_split_hook *s;
8e51e414	217	struct bio *n;
cafe5635 KO	218
	219	if (!bio_has_data(bio) && !(bio->bi_rw & REQ_DISCARD))
	220	goto submit;
	221
	222	if (bio_sectors(bio) <= bch_bio_max_sectors(bio))
	223	goto submit;
	224
	225	s = mempool_alloc(p->bio_split_hook, GFP_NOIO);
8e51e414	226	closure_init(&s->cl, NULL);
cafe5635 KO	227
	228	s->bio = bio;
	229	s->p = p;
	230	s->bi_end_io = bio->bi_end_io;
	231	s->bi_private = bio->bi_private;
	232	bio_get(bio);
	233
8e51e414 KO	234	do {
	235	n = bch_bio_split(bio, bch_bio_max_sectors(bio),
	236	GFP_NOIO, s->p->bio_split);
	237
	238	n->bi_end_io = bch_bio_submit_split_endio;
	239	n->bi_private = &s->cl;
	240
	241	closure_get(&s->cl);
	242	bch_generic_make_request_hack(n);
	243	} while (n != bio);
	244
	245	continue_at(&s->cl, bch_bio_submit_split_done, NULL);
cafe5635 KO	246	submit:
	247	bch_generic_make_request_hack(bio);
	248	}
	249
	250	/* Bios with headers */
	251
	252	void bch_bbio_free(struct bio bio, struct cache_set c)
	253	{
	254	struct bbio *b = container_of(bio, struct bbio, bio);
	255	mempool_free(b, c->bio_meta);
	256	}
	257
	258	struct bio bch_bbio_alloc(struct cache_set c)
	259	{
	260	struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO);
	261	struct bio *bio = &b->bio;
	262
	263	bio_init(bio);
	264	bio->bi_flags \|= BIO_POOL_NONE << BIO_POOL_OFFSET;
	265	bio->bi_max_vecs = bucket_pages(c);
	266	bio->bi_io_vec = bio->bi_inline_vecs;
	267
	268	return bio;
	269	}
	270
	271	void __bch_submit_bbio(struct bio bio, struct cache_set c)
	272	{
	273	struct bbio *b = container_of(bio, struct bbio, bio);
	274
	275	bio->bi_sector = PTR_OFFSET(&b->key, 0);
	276	bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev;
	277
	278	b->submit_time_us = local_clock_us();
	279	closure_bio_submit(bio, bio->bi_private, PTR_CACHE(c, &b->key, 0));
	280	}
	281
	282	void bch_submit_bbio(struct bio bio, struct cache_set c,
	283	struct bkey *k, unsigned ptr)
	284	{
	285	struct bbio *b = container_of(bio, struct bbio, bio);
	286	bch_bkey_copy_single_ptr(&b->key, k, ptr);
	287	__bch_submit_bbio(bio, c);
	288	}
	289
	290	/* IO errors */
	291
	292	void bch_count_io_errors(struct cache ca, int error, const char m)
	293	{
	294	/*
	295	* The halflife of an error is:
	296	* log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
	297	*/
	298
	299	if (ca->set->error_decay) {
	300	unsigned count = atomic_inc_return(&ca->io_count);
	301
	302	while (count > ca->set->error_decay) {
	303	unsigned errors;
	304	unsigned old = count;
	305	unsigned new = count - ca->set->error_decay;
	306
	307	/*
	308	* First we subtract refresh from count; each time we
	309	* succesfully do so, we rescale the errors once:
310	*/
311
312	count = atomic_cmpxchg(&ca->io_count, old, new);
313
314	if (count == old) {
315	count = new;
316
317	errors = atomic_read(&ca->io_errors);
318	do {
319	old = errors;
320	new = ((uint64_t) errors * 127) / 128;
321	errors = atomic_cmpxchg(&ca->io_errors,
322	old, new);
323	} while (old != errors);
324	}
325	}
326	}
327
328	if (error) {
329	char buf[BDEVNAME_SIZE];
330	unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT,
331	&ca->io_errors);
332	errors >>= IO_ERROR_SHIFT;
333
334	if (errors < ca->set->error_limit)
335	pr_err("%s: IO error on %s, recovering",
336	bdevname(ca->bdev, buf), m);
337	else
338	bch_cache_set_error(ca->set,
339	"%s: too many IO errors %s",
340	bdevname(ca->bdev, buf), m);
341	}
342	}
343
344	void bch_bbio_count_io_errors(struct cache_set c, struct bio bio,
345	int error, const char *m)
346	{
347	struct bbio *b = container_of(bio, struct bbio, bio);
348	struct cache *ca = PTR_CACHE(c, &b->key, 0);
349
350	unsigned threshold = bio->bi_rw & REQ_WRITE
351	? c->congested_write_threshold_us
352	: c->congested_read_threshold_us;
353
354	if (threshold) {
355	unsigned t = local_clock_us();
356
357	int us = t - b->submit_time_us;
358	int congested = atomic_read(&c->congested);
359
360	if (us > (int) threshold) {
361	int ms = us / 1024;
362	c->congested_last_us = t;
363
364	ms = min(ms, CONGESTED_MAX + congested);
365	atomic_sub(ms, &c->congested);
366	} else if (congested < 0)
367	atomic_inc(&c->congested);
368	}
369
370	bch_count_io_errors(ca, error, m);
371	}
372
373	void bch_bbio_endio(struct cache_set c, struct bio bio,
374	int error, const char *m)
375	{
376	struct closure *cl = bio->bi_private;
377
378	bch_bbio_count_io_errors(c, bio, error, m);
379	bio_put(bio);
380	closure_put(cl);
381	}