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74d46992e0
This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
142 lines
3.3 KiB
C
142 lines
3.3 KiB
C
/*
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* Some low level IO code, and hacks for various block layer limitations
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*
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* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
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* Copyright 2012 Google, Inc.
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*/
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#include "bcache.h"
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#include "bset.h"
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#include "debug.h"
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#include <linux/blkdev.h>
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/* Bios with headers */
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void bch_bbio_free(struct bio *bio, struct cache_set *c)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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mempool_free(b, c->bio_meta);
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}
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struct bio *bch_bbio_alloc(struct cache_set *c)
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{
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struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO);
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struct bio *bio = &b->bio;
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bio_init(bio, bio->bi_inline_vecs, bucket_pages(c));
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return bio;
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}
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void __bch_submit_bbio(struct bio *bio, struct cache_set *c)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0);
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bio_set_dev(bio, PTR_CACHE(c, &b->key, 0)->bdev);
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b->submit_time_us = local_clock_us();
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closure_bio_submit(bio, bio->bi_private);
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}
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void bch_submit_bbio(struct bio *bio, struct cache_set *c,
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struct bkey *k, unsigned ptr)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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bch_bkey_copy_single_ptr(&b->key, k, ptr);
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__bch_submit_bbio(bio, c);
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}
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/* IO errors */
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void bch_count_io_errors(struct cache *ca, blk_status_t error, const char *m)
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{
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/*
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* The halflife of an error is:
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* log2(1/2)/log2(127/128) * refresh ~= 88 * refresh
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*/
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if (ca->set->error_decay) {
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unsigned count = atomic_inc_return(&ca->io_count);
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while (count > ca->set->error_decay) {
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unsigned errors;
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unsigned old = count;
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unsigned new = count - ca->set->error_decay;
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/*
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* First we subtract refresh from count; each time we
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* succesfully do so, we rescale the errors once:
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*/
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count = atomic_cmpxchg(&ca->io_count, old, new);
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if (count == old) {
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count = new;
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errors = atomic_read(&ca->io_errors);
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do {
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old = errors;
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new = ((uint64_t) errors * 127) / 128;
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errors = atomic_cmpxchg(&ca->io_errors,
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old, new);
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} while (old != errors);
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}
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}
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}
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if (error) {
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char buf[BDEVNAME_SIZE];
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unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT,
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&ca->io_errors);
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errors >>= IO_ERROR_SHIFT;
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if (errors < ca->set->error_limit)
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pr_err("%s: IO error on %s, recovering",
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bdevname(ca->bdev, buf), m);
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else
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bch_cache_set_error(ca->set,
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"%s: too many IO errors %s",
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bdevname(ca->bdev, buf), m);
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}
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}
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void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio,
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blk_status_t error, const char *m)
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{
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struct bbio *b = container_of(bio, struct bbio, bio);
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struct cache *ca = PTR_CACHE(c, &b->key, 0);
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unsigned threshold = op_is_write(bio_op(bio))
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? c->congested_write_threshold_us
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: c->congested_read_threshold_us;
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if (threshold) {
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unsigned t = local_clock_us();
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int us = t - b->submit_time_us;
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int congested = atomic_read(&c->congested);
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if (us > (int) threshold) {
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int ms = us / 1024;
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c->congested_last_us = t;
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ms = min(ms, CONGESTED_MAX + congested);
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atomic_sub(ms, &c->congested);
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} else if (congested < 0)
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atomic_inc(&c->congested);
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}
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bch_count_io_errors(ca, error, m);
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}
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void bch_bbio_endio(struct cache_set *c, struct bio *bio,
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blk_status_t error, const char *m)
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{
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struct closure *cl = bio->bi_private;
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bch_bbio_count_io_errors(c, bio, error, m);
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bio_put(bio);
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closure_put(cl);
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}
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