/* * Functions related to barrier IO handling */ #include #include #include #include #include #include "blk.h" /** * blk_queue_ordered - does this queue support ordered writes * @q: the request queue * @ordered: one of QUEUE_ORDERED_* * @prepare_flush_fn: rq setup helper for cache flush ordered writes * * Description: * For journalled file systems, doing ordered writes on a commit * block instead of explicitly doing wait_on_buffer (which is bad * for performance) can be a big win. Block drivers supporting this * feature should call this function and indicate so. * **/ int blk_queue_ordered(struct request_queue *q, unsigned ordered, prepare_flush_fn *prepare_flush_fn) { if (!prepare_flush_fn && (ordered & (QUEUE_ORDERED_DO_PREFLUSH | QUEUE_ORDERED_DO_POSTFLUSH))) { printk(KERN_ERR "%s: prepare_flush_fn required\n", __func__); return -EINVAL; } if (ordered != QUEUE_ORDERED_NONE && ordered != QUEUE_ORDERED_DRAIN && ordered != QUEUE_ORDERED_DRAIN_FLUSH && ordered != QUEUE_ORDERED_DRAIN_FUA && ordered != QUEUE_ORDERED_TAG && ordered != QUEUE_ORDERED_TAG_FLUSH && ordered != QUEUE_ORDERED_TAG_FUA) { printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered); return -EINVAL; } q->ordered = ordered; q->next_ordered = ordered; q->prepare_flush_fn = prepare_flush_fn; return 0; } EXPORT_SYMBOL(blk_queue_ordered); /* * Cache flushing for ordered writes handling */ unsigned blk_ordered_cur_seq(struct request_queue *q) { if (!q->ordseq) return 0; return 1 << ffz(q->ordseq); } unsigned blk_ordered_req_seq(struct request *rq) { struct request_queue *q = rq->q; BUG_ON(q->ordseq == 0); if (rq == &q->pre_flush_rq) return QUEUE_ORDSEQ_PREFLUSH; if (rq == &q->bar_rq) return QUEUE_ORDSEQ_BAR; if (rq == &q->post_flush_rq) return QUEUE_ORDSEQ_POSTFLUSH; /* * !fs requests don't need to follow barrier ordering. Always * put them at the front. This fixes the following deadlock. * * http://thread.gmane.org/gmane.linux.kernel/537473 */ if (!blk_fs_request(rq)) return QUEUE_ORDSEQ_DRAIN; if ((rq->cmd_flags & REQ_ORDERED_COLOR) == (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR)) return QUEUE_ORDSEQ_DRAIN; else return QUEUE_ORDSEQ_DONE; } bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error) { struct request *rq; if (error && !q->orderr) q->orderr = error; BUG_ON(q->ordseq & seq); q->ordseq |= seq; if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE) return false; /* * Okay, sequence complete. */ q->ordseq = 0; rq = q->orig_bar_rq; __blk_end_request_all(rq, q->orderr); return true; } static void pre_flush_end_io(struct request *rq, int error) { elv_completed_request(rq->q, rq); blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error); } static void bar_end_io(struct request *rq, int error) { elv_completed_request(rq->q, rq); blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error); } static void post_flush_end_io(struct request *rq, int error) { elv_completed_request(rq->q, rq); blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error); } static void queue_flush(struct request_queue *q, unsigned which) { struct request *rq; rq_end_io_fn *end_io; if (which == QUEUE_ORDERED_DO_PREFLUSH) { rq = &q->pre_flush_rq; end_io = pre_flush_end_io; } else { rq = &q->post_flush_rq; end_io = post_flush_end_io; } blk_rq_init(q, rq); rq->cmd_flags = REQ_HARDBARRIER; rq->rq_disk = q->bar_rq.rq_disk; rq->end_io = end_io; q->prepare_flush_fn(q, rq); elv_insert(q, rq, ELEVATOR_INSERT_FRONT); } static inline bool start_ordered(struct request_queue *q, struct request **rqp) { struct request *rq = *rqp; unsigned skip = 0; q->orderr = 0; q->ordered = q->next_ordered; q->ordseq |= QUEUE_ORDSEQ_STARTED; /* * For an empty barrier, there's no actual BAR request, which * in turn makes POSTFLUSH unnecessary. Mask them off. */ if (!blk_rq_sectors(rq)) { q->ordered &= ~(QUEUE_ORDERED_DO_BAR | QUEUE_ORDERED_DO_POSTFLUSH); /* * Empty barrier on a write-through device w/ ordered * tag has no command to issue and without any command * to issue, ordering by tag can't be used. Drain * instead. */ if ((q->ordered & QUEUE_ORDERED_BY_TAG) && !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) { q->ordered &= ~QUEUE_ORDERED_BY_TAG; q->ordered |= QUEUE_ORDERED_BY_DRAIN; } } /* stash away the original request */ blk_dequeue_request(rq); q->orig_bar_rq = rq; rq = NULL; /* * Queue ordered sequence. As we stack them at the head, we * need to queue in reverse order. Note that we rely on that * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs * request gets inbetween ordered sequence. */ if (q->ordered & QUEUE_ORDERED_DO_POSTFLUSH) { queue_flush(q, QUEUE_ORDERED_DO_POSTFLUSH); rq = &q->post_flush_rq; } else skip |= QUEUE_ORDSEQ_POSTFLUSH; if (q->ordered & QUEUE_ORDERED_DO_BAR) { rq = &q->bar_rq; /* initialize proxy request and queue it */ blk_rq_init(q, rq); if (bio_data_dir(q->orig_bar_rq->bio) == WRITE) rq->cmd_flags |= REQ_RW; if (q->ordered & QUEUE_ORDERED_DO_FUA) rq->cmd_flags |= REQ_FUA; init_request_from_bio(rq, q->orig_bar_rq->bio); rq->end_io = bar_end_io; elv_insert(q, rq, ELEVATOR_INSERT_FRONT); } else skip |= QUEUE_ORDSEQ_BAR; if (q->ordered & QUEUE_ORDERED_DO_PREFLUSH) { queue_flush(q, QUEUE_ORDERED_DO_PREFLUSH); rq = &q->pre_flush_rq; } else skip |= QUEUE_ORDSEQ_PREFLUSH; if ((q->ordered & QUEUE_ORDERED_BY_DRAIN) && queue_in_flight(q)) rq = NULL; else skip |= QUEUE_ORDSEQ_DRAIN; *rqp = rq; /* * Complete skipped sequences. If whole sequence is complete, * return false to tell elevator that this request is gone. */ return !blk_ordered_complete_seq(q, skip, 0); } bool blk_do_ordered(struct request_queue *q, struct request **rqp) { struct request *rq = *rqp; const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq); if (!q->ordseq) { if (!is_barrier) return true; if (q->next_ordered != QUEUE_ORDERED_NONE) return start_ordered(q, rqp); else { /* * Queue ordering not supported. Terminate * with prejudice. */ blk_dequeue_request(rq); __blk_end_request_all(rq, -EOPNOTSUPP); *rqp = NULL; return false; } } /* * Ordered sequence in progress */ /* Special requests are not subject to ordering rules. */ if (!blk_fs_request(rq) && rq != &q->pre_flush_rq && rq != &q->post_flush_rq) return true; if (q->ordered & QUEUE_ORDERED_BY_TAG) { /* Ordered by tag. Blocking the next barrier is enough. */ if (is_barrier && rq != &q->bar_rq) *rqp = NULL; } else { /* Ordered by draining. Wait for turn. */ WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q)); if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q)) *rqp = NULL; } return true; } static void bio_end_empty_barrier(struct bio *bio, int err) { if (err) { if (err == -EOPNOTSUPP) set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); clear_bit(BIO_UPTODATE, &bio->bi_flags); } complete(bio->bi_private); } /** * blkdev_issue_flush - queue a flush * @bdev: blockdev to issue flush for * @error_sector: error sector * * Description: * Issue a flush for the block device in question. Caller can supply * room for storing the error offset in case of a flush error, if they * wish to. */ int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector) { DECLARE_COMPLETION_ONSTACK(wait); struct request_queue *q; struct bio *bio; int ret; if (bdev->bd_disk == NULL) return -ENXIO; q = bdev_get_queue(bdev); if (!q) return -ENXIO; bio = bio_alloc(GFP_KERNEL, 0); bio->bi_end_io = bio_end_empty_barrier; bio->bi_private = &wait; bio->bi_bdev = bdev; submit_bio(WRITE_BARRIER, bio); wait_for_completion(&wait); /* * The driver must store the error location in ->bi_sector, if * it supports it. For non-stacked drivers, this should be copied * from blk_rq_pos(rq). */ if (error_sector) *error_sector = bio->bi_sector; ret = 0; if (bio_flagged(bio, BIO_EOPNOTSUPP)) ret = -EOPNOTSUPP; else if (!bio_flagged(bio, BIO_UPTODATE)) ret = -EIO; bio_put(bio); return ret; } EXPORT_SYMBOL(blkdev_issue_flush); static void blkdev_discard_end_io(struct bio *bio, int err) { if (err) { if (err == -EOPNOTSUPP) set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); clear_bit(BIO_UPTODATE, &bio->bi_flags); } if (bio->bi_private) complete(bio->bi_private); __free_page(bio_page(bio)); bio_put(bio); } /** * blkdev_issue_discard - queue a discard * @bdev: blockdev to issue discard for * @sector: start sector * @nr_sects: number of sectors to discard * @gfp_mask: memory allocation flags (for bio_alloc) * @flags: DISCARD_FL_* flags to control behaviour * * Description: * Issue a discard request for the sectors in question. */ int blkdev_issue_discard(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, int flags) { DECLARE_COMPLETION_ONSTACK(wait); struct request_queue *q = bdev_get_queue(bdev); int type = flags & DISCARD_FL_BARRIER ? DISCARD_BARRIER : DISCARD_NOBARRIER; struct bio *bio; struct page *page; int ret = 0; if (!q) return -ENXIO; if (!blk_queue_discard(q)) return -EOPNOTSUPP; while (nr_sects && !ret) { unsigned int sector_size = q->limits.logical_block_size; unsigned int max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); bio = bio_alloc(gfp_mask, 1); if (!bio) goto out; bio->bi_sector = sector; bio->bi_end_io = blkdev_discard_end_io; bio->bi_bdev = bdev; if (flags & DISCARD_FL_WAIT) bio->bi_private = &wait; /* * Add a zeroed one-sector payload as that's what * our current implementations need. If we'll ever need * more the interface will need revisiting. */ page = alloc_page(gfp_mask | __GFP_ZERO); if (!page) goto out_free_bio; if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size) goto out_free_page; /* * And override the bio size - the way discard works we * touch many more blocks on disk than the actual payload * length. */ if (nr_sects > max_discard_sectors) { bio->bi_size = max_discard_sectors << 9; nr_sects -= max_discard_sectors; sector += max_discard_sectors; } else { bio->bi_size = nr_sects << 9; nr_sects = 0; } bio_get(bio); submit_bio(type, bio); if (flags & DISCARD_FL_WAIT) wait_for_completion(&wait); if (bio_flagged(bio, BIO_EOPNOTSUPP)) ret = -EOPNOTSUPP; else if (!bio_flagged(bio, BIO_UPTODATE)) ret = -EIO; bio_put(bio); } return ret; out_free_page: __free_page(page); out_free_bio: bio_put(bio); out: return -ENOMEM; } EXPORT_SYMBOL(blkdev_issue_discard); value='feature/benchmarks'>feature/benchmarks main, development code repositoryroot
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2020-07-09unotools: create instances with uno constructorsNoel Grandin1-3/+5
2015-09-19add implementation for theServiceDocumenter singletonBjoern Michaelsen1-0/+3
2013-12-17Adapt all (non-extension, SharedLibrary) .components to environment="..."Stephan Bergmann1-2/+2