| /* |
| * Copyright (C) 2016 Red Hat, Inc. All rights reserved. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm-core.h" |
| #include "dm-rq.h" |
| |
| #include <linux/elevator.h> /* for rq_end_sector() */ |
| #include <linux/blk-mq.h> |
| |
| #define DM_MSG_PREFIX "core-rq" |
| |
| /* |
| * One of these is allocated per request. |
| */ |
| struct dm_rq_target_io { |
| struct mapped_device *md; |
| struct dm_target *ti; |
| struct request *orig, *clone; |
| struct kthread_work work; |
| blk_status_t error; |
| union map_info info; |
| struct dm_stats_aux stats_aux; |
| unsigned long duration_jiffies; |
| unsigned n_sectors; |
| unsigned completed; |
| }; |
| |
| #define DM_MQ_NR_HW_QUEUES 1 |
| #define DM_MQ_QUEUE_DEPTH 2048 |
| static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES; |
| static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH; |
| |
| /* |
| * Request-based DM's mempools' reserved IOs set by the user. |
| */ |
| #define RESERVED_REQUEST_BASED_IOS 256 |
| static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS; |
| |
| unsigned dm_get_reserved_rq_based_ios(void) |
| { |
| return __dm_get_module_param(&reserved_rq_based_ios, |
| RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS); |
| } |
| EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios); |
| |
| static unsigned dm_get_blk_mq_nr_hw_queues(void) |
| { |
| return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32); |
| } |
| |
| static unsigned dm_get_blk_mq_queue_depth(void) |
| { |
| return __dm_get_module_param(&dm_mq_queue_depth, |
| DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH); |
| } |
| |
| int dm_request_based(struct mapped_device *md) |
| { |
| return queue_is_mq(md->queue); |
| } |
| |
| void dm_start_queue(struct request_queue *q) |
| { |
| blk_mq_unquiesce_queue(q); |
| blk_mq_kick_requeue_list(q); |
| } |
| |
| void dm_stop_queue(struct request_queue *q) |
| { |
| blk_mq_quiesce_queue(q); |
| } |
| |
| /* |
| * Partial completion handling for request-based dm |
| */ |
| static void end_clone_bio(struct bio *clone) |
| { |
| struct dm_rq_clone_bio_info *info = |
| container_of(clone, struct dm_rq_clone_bio_info, clone); |
| struct dm_rq_target_io *tio = info->tio; |
| unsigned int nr_bytes = info->orig->bi_iter.bi_size; |
| blk_status_t error = clone->bi_status; |
| bool is_last = !clone->bi_next; |
| |
| bio_put(clone); |
| |
| if (tio->error) |
| /* |
| * An error has already been detected on the request. |
| * Once error occurred, just let clone->end_io() handle |
| * the remainder. |
| */ |
| return; |
| else if (error) { |
| /* |
| * Don't notice the error to the upper layer yet. |
| * The error handling decision is made by the target driver, |
| * when the request is completed. |
| */ |
| tio->error = error; |
| goto exit; |
| } |
| |
| /* |
| * I/O for the bio successfully completed. |
| * Notice the data completion to the upper layer. |
| */ |
| tio->completed += nr_bytes; |
| |
| /* |
| * Update the original request. |
| * Do not use blk_mq_end_request() here, because it may complete |
| * the original request before the clone, and break the ordering. |
| */ |
| if (is_last) |
| exit: |
| blk_update_request(tio->orig, BLK_STS_OK, tio->completed); |
| } |
| |
| static struct dm_rq_target_io *tio_from_request(struct request *rq) |
| { |
| return blk_mq_rq_to_pdu(rq); |
| } |
| |
| static void rq_end_stats(struct mapped_device *md, struct request *orig) |
| { |
| if (unlikely(dm_stats_used(&md->stats))) { |
| struct dm_rq_target_io *tio = tio_from_request(orig); |
| tio->duration_jiffies = jiffies - tio->duration_jiffies; |
| dm_stats_account_io(&md->stats, rq_data_dir(orig), |
| blk_rq_pos(orig), tio->n_sectors, true, |
| tio->duration_jiffies, &tio->stats_aux); |
| } |
| } |
| |
| /* |
| * Don't touch any member of the md after calling this function because |
| * the md may be freed in dm_put() at the end of this function. |
| * Or do dm_get() before calling this function and dm_put() later. |
| */ |
| static void rq_completed(struct mapped_device *md) |
| { |
| /* |
| * dm_put() must be at the end of this function. See the comment above |
| */ |
| dm_put(md); |
| } |
| |
| /* |
| * Complete the clone and the original request. |
| * Must be called without clone's queue lock held, |
| * see end_clone_request() for more details. |
| */ |
| static void dm_end_request(struct request *clone, blk_status_t error) |
| { |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| struct mapped_device *md = tio->md; |
| struct request *rq = tio->orig; |
| |
| blk_rq_unprep_clone(clone); |
| tio->ti->type->release_clone_rq(clone, NULL); |
| |
| rq_end_stats(md, rq); |
| blk_mq_end_request(rq, error); |
| rq_completed(md); |
| } |
| |
| static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs) |
| { |
| blk_mq_delay_kick_requeue_list(q, msecs); |
| } |
| |
| void dm_mq_kick_requeue_list(struct mapped_device *md) |
| { |
| __dm_mq_kick_requeue_list(md->queue, 0); |
| } |
| EXPORT_SYMBOL(dm_mq_kick_requeue_list); |
| |
| static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs) |
| { |
| blk_mq_requeue_request(rq, false); |
| __dm_mq_kick_requeue_list(rq->q, msecs); |
| } |
| |
| static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue) |
| { |
| struct mapped_device *md = tio->md; |
| struct request *rq = tio->orig; |
| unsigned long delay_ms = delay_requeue ? 100 : 0; |
| |
| rq_end_stats(md, rq); |
| if (tio->clone) { |
| blk_rq_unprep_clone(tio->clone); |
| tio->ti->type->release_clone_rq(tio->clone, NULL); |
| } |
| |
| dm_mq_delay_requeue_request(rq, delay_ms); |
| rq_completed(md); |
| } |
| |
| static void dm_done(struct request *clone, blk_status_t error, bool mapped) |
| { |
| int r = DM_ENDIO_DONE; |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| dm_request_endio_fn rq_end_io = NULL; |
| |
| if (tio->ti) { |
| rq_end_io = tio->ti->type->rq_end_io; |
| |
| if (mapped && rq_end_io) |
| r = rq_end_io(tio->ti, clone, error, &tio->info); |
| } |
| |
| if (unlikely(error == BLK_STS_TARGET)) { |
| if (req_op(clone) == REQ_OP_DISCARD && |
| !clone->q->limits.max_discard_sectors) |
| disable_discard(tio->md); |
| else if (req_op(clone) == REQ_OP_WRITE_SAME && |
| !clone->q->limits.max_write_same_sectors) |
| disable_write_same(tio->md); |
| else if (req_op(clone) == REQ_OP_WRITE_ZEROES && |
| !clone->q->limits.max_write_zeroes_sectors) |
| disable_write_zeroes(tio->md); |
| } |
| |
| switch (r) { |
| case DM_ENDIO_DONE: |
| /* The target wants to complete the I/O */ |
| dm_end_request(clone, error); |
| break; |
| case DM_ENDIO_INCOMPLETE: |
| /* The target will handle the I/O */ |
| return; |
| case DM_ENDIO_REQUEUE: |
| /* The target wants to requeue the I/O */ |
| dm_requeue_original_request(tio, false); |
| break; |
| case DM_ENDIO_DELAY_REQUEUE: |
| /* The target wants to requeue the I/O after a delay */ |
| dm_requeue_original_request(tio, true); |
| break; |
| default: |
| DMWARN("unimplemented target endio return value: %d", r); |
| BUG(); |
| } |
| } |
| |
| /* |
| * Request completion handler for request-based dm |
| */ |
| static void dm_softirq_done(struct request *rq) |
| { |
| bool mapped = true; |
| struct dm_rq_target_io *tio = tio_from_request(rq); |
| struct request *clone = tio->clone; |
| |
| if (!clone) { |
| struct mapped_device *md = tio->md; |
| |
| rq_end_stats(md, rq); |
| blk_mq_end_request(rq, tio->error); |
| rq_completed(md); |
| return; |
| } |
| |
| if (rq->rq_flags & RQF_FAILED) |
| mapped = false; |
| |
| dm_done(clone, tio->error, mapped); |
| } |
| |
| /* |
| * Complete the clone and the original request with the error status |
| * through softirq context. |
| */ |
| static void dm_complete_request(struct request *rq, blk_status_t error) |
| { |
| struct dm_rq_target_io *tio = tio_from_request(rq); |
| |
| tio->error = error; |
| if (likely(!blk_should_fake_timeout(rq->q))) |
| blk_mq_complete_request(rq); |
| } |
| |
| /* |
| * Complete the not-mapped clone and the original request with the error status |
| * through softirq context. |
| * Target's rq_end_io() function isn't called. |
| * This may be used when the target's clone_and_map_rq() function fails. |
| */ |
| static void dm_kill_unmapped_request(struct request *rq, blk_status_t error) |
| { |
| rq->rq_flags |= RQF_FAILED; |
| dm_complete_request(rq, error); |
| } |
| |
| static void end_clone_request(struct request *clone, blk_status_t error) |
| { |
| struct dm_rq_target_io *tio = clone->end_io_data; |
| |
| dm_complete_request(tio->orig, error); |
| } |
| |
| static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq) |
| { |
| blk_status_t r; |
| |
| if (blk_queue_io_stat(clone->q)) |
| clone->rq_flags |= RQF_IO_STAT; |
| |
| clone->start_time_ns = ktime_get_ns(); |
| r = blk_insert_cloned_request(clone->q, clone); |
| if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE) |
| /* must complete clone in terms of original request */ |
| dm_complete_request(rq, r); |
| return r; |
| } |
| |
| static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, |
| void *data) |
| { |
| struct dm_rq_target_io *tio = data; |
| struct dm_rq_clone_bio_info *info = |
| container_of(bio, struct dm_rq_clone_bio_info, clone); |
| |
| info->orig = bio_orig; |
| info->tio = tio; |
| bio->bi_end_io = end_clone_bio; |
| |
| return 0; |
| } |
| |
| static int setup_clone(struct request *clone, struct request *rq, |
| struct dm_rq_target_io *tio, gfp_t gfp_mask) |
| { |
| int r; |
| |
| r = blk_rq_prep_clone(clone, rq, &tio->md->bs, gfp_mask, |
| dm_rq_bio_constructor, tio); |
| if (r) |
| return r; |
| |
| clone->end_io = end_clone_request; |
| clone->end_io_data = tio; |
| |
| tio->clone = clone; |
| |
| return 0; |
| } |
| |
| static void init_tio(struct dm_rq_target_io *tio, struct request *rq, |
| struct mapped_device *md) |
| { |
| tio->md = md; |
| tio->ti = NULL; |
| tio->clone = NULL; |
| tio->orig = rq; |
| tio->error = 0; |
| tio->completed = 0; |
| /* |
| * Avoid initializing info for blk-mq; it passes |
| * target-specific data through info.ptr |
| * (see: dm_mq_init_request) |
| */ |
| if (!md->init_tio_pdu) |
| memset(&tio->info, 0, sizeof(tio->info)); |
| } |
| |
| /* |
| * Returns: |
| * DM_MAPIO_* : the request has been processed as indicated |
| * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued |
| * < 0 : the request was completed due to failure |
| */ |
| static int map_request(struct dm_rq_target_io *tio) |
| { |
| int r; |
| struct dm_target *ti = tio->ti; |
| struct mapped_device *md = tio->md; |
| struct request *rq = tio->orig; |
| struct request *clone = NULL; |
| blk_status_t ret; |
| |
| r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone); |
| switch (r) { |
| case DM_MAPIO_SUBMITTED: |
| /* The target has taken the I/O to submit by itself later */ |
| break; |
| case DM_MAPIO_REMAPPED: |
| if (setup_clone(clone, rq, tio, GFP_ATOMIC)) { |
| /* -ENOMEM */ |
| ti->type->release_clone_rq(clone, &tio->info); |
| return DM_MAPIO_REQUEUE; |
| } |
| |
| /* The target has remapped the I/O so dispatch it */ |
| trace_block_rq_remap(clone, disk_devt(dm_disk(md)), |
| blk_rq_pos(rq)); |
| ret = dm_dispatch_clone_request(clone, rq); |
| if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { |
| blk_rq_unprep_clone(clone); |
| blk_mq_cleanup_rq(clone); |
| tio->ti->type->release_clone_rq(clone, &tio->info); |
| tio->clone = NULL; |
| return DM_MAPIO_REQUEUE; |
| } |
| break; |
| case DM_MAPIO_REQUEUE: |
| /* The target wants to requeue the I/O */ |
| break; |
| case DM_MAPIO_DELAY_REQUEUE: |
| /* The target wants to requeue the I/O after a delay */ |
| dm_requeue_original_request(tio, true); |
| break; |
| case DM_MAPIO_KILL: |
| /* The target wants to complete the I/O */ |
| dm_kill_unmapped_request(rq, BLK_STS_IOERR); |
| break; |
| default: |
| DMWARN("unimplemented target map return value: %d", r); |
| BUG(); |
| } |
| |
| return r; |
| } |
| |
| /* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */ |
| ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf) |
| { |
| return sprintf(buf, "%u\n", 0); |
| } |
| |
| ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md, |
| const char *buf, size_t count) |
| { |
| return count; |
| } |
| |
| static void dm_start_request(struct mapped_device *md, struct request *orig) |
| { |
| blk_mq_start_request(orig); |
| |
| if (unlikely(dm_stats_used(&md->stats))) { |
| struct dm_rq_target_io *tio = tio_from_request(orig); |
| tio->duration_jiffies = jiffies; |
| tio->n_sectors = blk_rq_sectors(orig); |
| dm_stats_account_io(&md->stats, rq_data_dir(orig), |
| blk_rq_pos(orig), tio->n_sectors, false, 0, |
| &tio->stats_aux); |
| } |
| |
| /* |
| * Hold the md reference here for the in-flight I/O. |
| * We can't rely on the reference count by device opener, |
| * because the device may be closed during the request completion |
| * when all bios are completed. |
| * See the comment in rq_completed() too. |
| */ |
| dm_get(md); |
| } |
| |
| static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, |
| unsigned int hctx_idx, unsigned int numa_node) |
| { |
| struct mapped_device *md = set->driver_data; |
| struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); |
| |
| /* |
| * Must initialize md member of tio, otherwise it won't |
| * be available in dm_mq_queue_rq. |
| */ |
| tio->md = md; |
| |
| if (md->init_tio_pdu) { |
| /* target-specific per-io data is immediately after the tio */ |
| tio->info.ptr = tio + 1; |
| } |
| |
| return 0; |
| } |
| |
| static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, |
| const struct blk_mq_queue_data *bd) |
| { |
| struct request *rq = bd->rq; |
| struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); |
| struct mapped_device *md = tio->md; |
| struct dm_target *ti = md->immutable_target; |
| |
| if (unlikely(!ti)) { |
| int srcu_idx; |
| struct dm_table *map = dm_get_live_table(md, &srcu_idx); |
| |
| ti = dm_table_find_target(map, 0); |
| dm_put_live_table(md, srcu_idx); |
| } |
| |
| if (ti->type->busy && ti->type->busy(ti)) |
| return BLK_STS_RESOURCE; |
| |
| dm_start_request(md, rq); |
| |
| /* Init tio using md established in .init_request */ |
| init_tio(tio, rq, md); |
| |
| /* |
| * Establish tio->ti before calling map_request(). |
| */ |
| tio->ti = ti; |
| |
| /* Direct call is fine since .queue_rq allows allocations */ |
| if (map_request(tio) == DM_MAPIO_REQUEUE) { |
| /* Undo dm_start_request() before requeuing */ |
| rq_end_stats(md, rq); |
| rq_completed(md); |
| return BLK_STS_RESOURCE; |
| } |
| |
| return BLK_STS_OK; |
| } |
| |
| static const struct blk_mq_ops dm_mq_ops = { |
| .queue_rq = dm_mq_queue_rq, |
| .complete = dm_softirq_done, |
| .init_request = dm_mq_init_request, |
| }; |
| |
| int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) |
| { |
| struct dm_target *immutable_tgt; |
| int err; |
| |
| md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id); |
| if (!md->tag_set) |
| return -ENOMEM; |
| |
| md->tag_set->ops = &dm_mq_ops; |
| md->tag_set->queue_depth = dm_get_blk_mq_queue_depth(); |
| md->tag_set->numa_node = md->numa_node_id; |
| md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING; |
| md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); |
| md->tag_set->driver_data = md; |
| |
| md->tag_set->cmd_size = sizeof(struct dm_rq_target_io); |
| immutable_tgt = dm_table_get_immutable_target(t); |
| if (immutable_tgt && immutable_tgt->per_io_data_size) { |
| /* any target-specific per-io data is immediately after the tio */ |
| md->tag_set->cmd_size += immutable_tgt->per_io_data_size; |
| md->init_tio_pdu = true; |
| } |
| |
| err = blk_mq_alloc_tag_set(md->tag_set); |
| if (err) |
| goto out_kfree_tag_set; |
| |
| err = blk_mq_init_allocated_queue(md->tag_set, md->queue); |
| if (err) |
| goto out_tag_set; |
| return 0; |
| |
| out_tag_set: |
| blk_mq_free_tag_set(md->tag_set); |
| out_kfree_tag_set: |
| kfree(md->tag_set); |
| md->tag_set = NULL; |
| |
| return err; |
| } |
| |
| void dm_mq_cleanup_mapped_device(struct mapped_device *md) |
| { |
| if (md->tag_set) { |
| blk_mq_free_tag_set(md->tag_set); |
| kfree(md->tag_set); |
| md->tag_set = NULL; |
| } |
| } |
| |
| module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"); |
| |
| /* Unused, but preserved for userspace compatibility */ |
| static bool use_blk_mq = true; |
| module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices"); |
| |
| module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices"); |
| |
| module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices"); |