diff options
Diffstat (limited to 'drivers/md/dm-rq.c')
| -rw-r--r-- | drivers/md/dm-rq.c | 970 |
1 files changed, 970 insertions, 0 deletions
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c new file mode 100644 index 000000000000..7a9661868496 --- /dev/null +++ b/drivers/md/dm-rq.c @@ -0,0 +1,970 @@ +/* + * 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" + +#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; + +#ifdef CONFIG_DM_MQ_DEFAULT +static bool use_blk_mq = true; +#else +static bool use_blk_mq = false; +#endif + +bool dm_use_blk_mq_default(void) +{ + return use_blk_mq; +} + +bool dm_use_blk_mq(struct mapped_device *md) +{ + return md->use_blk_mq; +} +EXPORT_SYMBOL_GPL(dm_use_blk_mq); + +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 blk_queue_stackable(md->queue); +} + +static void dm_old_start_queue(struct request_queue *q) +{ + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + if (blk_queue_stopped(q)) + blk_start_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +void dm_start_queue(struct request_queue *q) +{ + if (!q->mq_ops) + dm_old_start_queue(q); + else { + blk_mq_start_stopped_hw_queues(q, true); + blk_mq_kick_requeue_list(q); + } +} + +static void dm_old_stop_queue(struct request_queue *q) +{ + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + if (blk_queue_stopped(q)) { + spin_unlock_irqrestore(q->queue_lock, flags); + return; + } + + blk_stop_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +void dm_stop_queue(struct request_queue *q) +{ + if (!q->mq_ops) + dm_old_stop_queue(q); + else + blk_mq_stop_hw_queues(q); +} + +static struct dm_rq_target_io *alloc_old_rq_tio(struct mapped_device *md, + gfp_t gfp_mask) +{ + return mempool_alloc(md->io_pool, gfp_mask); +} + +static void free_old_rq_tio(struct dm_rq_target_io *tio) +{ + mempool_free(tio, tio->md->io_pool); +} + +static struct request *alloc_old_clone_request(struct mapped_device *md, + gfp_t gfp_mask) +{ + return mempool_alloc(md->rq_pool, gfp_mask); +} + +static void free_old_clone_request(struct mapped_device *md, struct request *rq) +{ + mempool_free(rq, md->rq_pool); +} + +/* + * 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; + struct bio *bio = info->orig; + unsigned int nr_bytes = info->orig->bi_iter.bi_size; + int error = clone->bi_error; + + 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; + return; + } + + /* + * I/O for the bio successfully completed. + * Notice the data completion to the upper layer. + */ + + /* + * bios are processed from the head of the list. + * So the completing bio should always be rq->bio. + * If it's not, something wrong is happening. + */ + if (tio->orig->bio != bio) + DMERR("bio completion is going in the middle of the request"); + + /* + * Update the original request. + * Do not use blk_end_request() here, because it may complete + * the original request before the clone, and break the ordering. + */ + blk_update_request(tio->orig, 0, nr_bytes); +} + +static struct dm_rq_target_io *tio_from_request(struct request *rq) +{ + return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special); +} + +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, int rw, bool run_queue) +{ + atomic_dec(&md->pending[rw]); + + /* nudge anyone waiting on suspend queue */ + if (!md_in_flight(md)) + wake_up(&md->wait); + + /* + * Run this off this callpath, as drivers could invoke end_io while + * inside their request_fn (and holding the queue lock). Calling + * back into ->request_fn() could deadlock attempting to grab the + * queue lock again. + */ + if (!md->queue->mq_ops && run_queue) + blk_run_queue_async(md->queue); + + /* + * dm_put() must be at the end of this function. See the comment above + */ + dm_put(md); +} + +static void free_rq_clone(struct request *clone) +{ + struct dm_rq_target_io *tio = clone->end_io_data; + struct mapped_device *md = tio->md; + + blk_rq_unprep_clone(clone); + + /* + * It is possible for a clone_old_rq() allocated clone to + * get passed in -- it may not yet have a request_queue. + * This is known to occur if the error target replaces + * a multipath target that has a request_fn queue stacked + * on blk-mq queue(s). + */ + if (clone->q && clone->q->mq_ops) + /* stacked on blk-mq queue(s) */ + tio->ti->type->release_clone_rq(clone); + else if (!md->queue->mq_ops) + /* request_fn queue stacked on request_fn queue(s) */ + free_old_clone_request(md, clone); + + if (!md->queue->mq_ops) + free_old_rq_tio(tio); +} + +/* + * 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, int error) +{ + int rw = rq_data_dir(clone); + struct dm_rq_target_io *tio = clone->end_io_data; + struct mapped_device *md = tio->md; + struct request *rq = tio->orig; + + if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { + rq->errors = clone->errors; + rq->resid_len = clone->resid_len; + + if (rq->sense) + /* + * We are using the sense buffer of the original + * request. + * So setting the length of the sense data is enough. + */ + rq->sense_len = clone->sense_len; + } + + free_rq_clone(clone); + rq_end_stats(md, rq); + if (!rq->q->mq_ops) + blk_end_request_all(rq, error); + else + blk_mq_end_request(rq, error); + rq_completed(md, rw, true); +} + +static void dm_unprep_request(struct request *rq) +{ + struct dm_rq_target_io *tio = tio_from_request(rq); + struct request *clone = tio->clone; + + if (!rq->q->mq_ops) { + rq->special = NULL; + rq->cmd_flags &= ~REQ_DONTPREP; + } + + if (clone) + free_rq_clone(clone); + else if (!tio->md->queue->mq_ops) + free_old_rq_tio(tio); +} + +/* + * Requeue the original request of a clone. + */ +static void dm_old_requeue_request(struct request *rq) +{ + struct request_queue *q = rq->q; + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + blk_requeue_request(q, rq); + blk_run_queue_async(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +static void dm_mq_requeue_request(struct request *rq) +{ + struct request_queue *q = rq->q; + unsigned long flags; + + blk_mq_requeue_request(rq); + spin_lock_irqsave(q->queue_lock, flags); + if (!blk_queue_stopped(q)) + blk_mq_kick_requeue_list(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +static void dm_requeue_original_request(struct mapped_device *md, + struct request *rq) +{ + int rw = rq_data_dir(rq); + + rq_end_stats(md, rq); + dm_unprep_request(rq); + + if (!rq->q->mq_ops) + dm_old_requeue_request(rq); + else + dm_mq_requeue_request(rq); + + rq_completed(md, rw, false); +} + +static void dm_done(struct request *clone, int error, bool mapped) +{ + int r = error; + 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(r == -EREMOTEIO && (req_op(clone) == REQ_OP_WRITE_SAME) && + !clone->q->limits.max_write_same_sectors)) + disable_write_same(tio->md); + + if (r <= 0) + /* The target wants to complete the I/O */ + dm_end_request(clone, r); + else if (r == DM_ENDIO_INCOMPLETE) + /* The target will handle the I/O */ + return; + else if (r == DM_ENDIO_REQUEUE) + /* The target wants to requeue the I/O */ + dm_requeue_original_request(tio->md, tio->orig); + else { + 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; + int rw; + + if (!clone) { + rq_end_stats(tio->md, rq); + rw = rq_data_dir(rq); + if (!rq->q->mq_ops) { + blk_end_request_all(rq, tio->error); + rq_completed(tio->md, rw, false); + free_old_rq_tio(tio); + } else { + blk_mq_end_request(rq, tio->error); + rq_completed(tio->md, rw, false); + } + return; + } + + if (rq->cmd_flags & REQ_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, int error) +{ + struct dm_rq_target_io *tio = tio_from_request(rq); + + tio->error = error; + if (!rq->q->mq_ops) + blk_complete_request(rq); + else + blk_mq_complete_request(rq, error); +} + +/* + * 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 map_rq() or clone_and_map_rq() functions fail. + */ +static void dm_kill_unmapped_request(struct request *rq, int error) +{ + rq->cmd_flags |= REQ_FAILED; + dm_complete_request(rq, error); +} + +/* + * Called with the clone's queue lock held (in the case of .request_fn) + */ +static void end_clone_request(struct request *clone, int error) +{ + struct dm_rq_target_io *tio = clone->end_io_data; + + if (!clone->q->mq_ops) { + /* + * For just cleaning up the information of the queue in which + * the clone was dispatched. + * The clone is *NOT* freed actually here because it is alloced + * from dm own mempool (REQ_ALLOCED isn't set). + */ + __blk_put_request(clone->q, clone); + } + + /* + * Actual request completion is done in a softirq context which doesn't + * hold the clone's queue lock. Otherwise, deadlock could occur because: + * - another request may be submitted by the upper level driver + * of the stacking during the completion + * - the submission which requires queue lock may be done + * against this clone's queue + */ + dm_complete_request(tio->orig, error); +} + +static void dm_dispatch_clone_request(struct request *clone, struct request *rq) +{ + int r; + + if (blk_queue_io_stat(clone->q)) + clone->cmd_flags |= REQ_IO_STAT; + + clone->start_time = jiffies; + r = blk_insert_cloned_request(clone->q, clone); + if (r) + /* must complete clone in terms of original request */ + dm_complete_request(rq, 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->cmd = rq->cmd; + clone->cmd_len = rq->cmd_len; + clone->sense = rq->sense; + clone->end_io = end_clone_request; + clone->end_io_data = tio; + + tio->clone = clone; + + return 0; +} + +static struct request *clone_old_rq(struct request *rq, struct mapped_device *md, + struct dm_rq_target_io *tio, gfp_t gfp_mask) +{ + /* + * Create clone for use with .request_fn request_queue + */ + struct request *clone; + + clone = alloc_old_clone_request(md, gfp_mask); + if (!clone) + return NULL; + + blk_rq_init(NULL, clone); + if (setup_clone(clone, rq, tio, gfp_mask)) { + /* -ENOMEM */ + free_old_clone_request(md, clone); + return NULL; + } + + return clone; +} + +static void map_tio_request(struct kthread_work *work); + +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; + /* + * 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)); + if (md->kworker_task) + init_kthread_work(&tio->work, map_tio_request); +} + +static struct dm_rq_target_io *dm_old_prep_tio(struct request *rq, + struct mapped_device *md, + gfp_t gfp_mask) +{ + struct dm_rq_target_io *tio; + int srcu_idx; + struct dm_table *table; + + tio = alloc_old_rq_tio(md, gfp_mask); + if (!tio) + return NULL; + + init_tio(tio, rq, md); + + table = dm_get_live_table(md, &srcu_idx); + /* + * Must clone a request if this .request_fn DM device + * is stacked on .request_fn device(s). + */ + if (!dm_table_all_blk_mq_devices(table)) { + if (!clone_old_rq(rq, md, tio, gfp_mask)) { + dm_put_live_table(md, srcu_idx); + free_old_rq_tio(tio); + return NULL; + } + } + dm_put_live_table(md, srcu_idx); + + return tio; +} + +/* + * Called with the queue lock held. + */ +static int dm_old_prep_fn(struct request_queue *q, struct request *rq) +{ + struct mapped_device *md = q->queuedata; + struct dm_rq_target_io *tio; + + if (unlikely(rq->special)) { + DMWARN("Already has something in rq->special."); + return BLKPREP_KILL; + } + + tio = dm_old_prep_tio(rq, md, GFP_ATOMIC); + if (!tio) + return BLKPREP_DEFER; + + rq->special = tio; + rq->cmd_flags |= REQ_DONTPREP; + + return BLKPREP_OK; +} + +/* + * Returns: + * 0 : the request has been processed + * DM_MAPIO_REQUEUE : the original request needs to be requeued + * < 0 : the request was completed due to failure + */ +static int map_request(struct dm_rq_target_io *tio, struct request *rq, + struct mapped_device *md) +{ + int r; + struct dm_target *ti = tio->ti; + struct request *clone = NULL; + + if (tio->clone) { + clone = tio->clone; + r = ti->type->map_rq(ti, clone, &tio->info); + } else { + r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone); + if (r < 0) { + /* The target wants to complete the I/O */ + dm_kill_unmapped_request(rq, r); + return r; + } + if (r != DM_MAPIO_REMAPPED) + return r; + if (setup_clone(clone, rq, tio, GFP_ATOMIC)) { + /* -ENOMEM */ + ti->type->release_clone_rq(clone); + return DM_MAPIO_REQUEUE; + } + } + + switch (r) { + case DM_MAPIO_SUBMITTED: + /* The target has taken the I/O to submit by itself later */ + break; + case DM_MAPIO_REMAPPED: + /* The target has remapped the I/O so dispatch it */ + trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), + blk_rq_pos(rq)); + dm_dispatch_clone_request(clone, rq); + break; + case DM_MAPIO_REQUEUE: + /* The target wants to requeue the I/O */ + dm_requeue_original_request(md, tio->orig); + break; + default: + if (r > 0) { + DMWARN("unimplemented target map return value: %d", r); + BUG(); + } + + /* The target wants to complete the I/O */ + dm_kill_unmapped_request(rq, r); + return r; + } + + return 0; +} + +static void dm_start_request(struct mapped_device *md, struct request *orig) +{ + if (!orig->q->mq_ops) + blk_start_request(orig); + else + blk_mq_start_request(orig); + atomic_inc(&md->pending[rq_data_dir(orig)]); + + if (md->seq_rq_merge_deadline_usecs) { + md->last_rq_pos = rq_end_sector(orig); + md->last_rq_rw = rq_data_dir(orig); + md->last_rq_start_time = ktime_get(); + } + + 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 void map_tio_request(struct kthread_work *work) +{ + struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work); + struct request *rq = tio->orig; + struct mapped_device *md = tio->md; + + if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) + dm_requeue_original_request(md, rq); +} + +ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf) +{ + return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs); +} + +#define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000 + +ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md, + const char *buf, size_t count) +{ + unsigned deadline; + + if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED) + return count; + + if (kstrtouint(buf, 10, &deadline)) + return -EINVAL; + + if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS) + deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS; + + md->seq_rq_merge_deadline_usecs = deadline; + + return count; +} + +static bool dm_old_request_peeked_before_merge_deadline(struct mapped_device *md) +{ + ktime_t kt_deadline; + + if (!md->seq_rq_merge_deadline_usecs) + return false; + + kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC); + kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline); + + return !ktime_after(ktime_get(), kt_deadline); +} + +/* + * q->request_fn for old request-based dm. + * Called with the queue lock held. + */ +static void dm_old_request_fn(struct request_queue *q) +{ + struct mapped_device *md = q->queuedata; + struct dm_target *ti = md->immutable_target; + struct request *rq; + struct dm_rq_target_io *tio; + sector_t pos = 0; + + if (unlikely(!ti)) { + int srcu_idx; + struct dm_table *map = dm_get_live_table(md, &srcu_idx); + + ti = dm_table_find_target(map, pos); + dm_put_live_table(md, srcu_idx); + } + + /* + * For suspend, check blk_queue_stopped() and increment + * ->pending within a single queue_lock not to increment the + * number of in-flight I/Os after the queue is stopped in + * dm_suspend(). + */ + while (!blk_queue_stopped(q)) { + rq = blk_peek_request(q); + if (!rq) + return; + + /* always use block 0 to find the target for flushes for now */ + pos = 0; + if (req_op(rq) != REQ_OP_FLUSH) + pos = blk_rq_pos(rq); + + if ((dm_old_request_peeked_before_merge_deadline(md) && + md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 && + md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) || + (ti->type->busy && ti->type->busy(ti))) { + blk_delay_queue(q, 10); + return; + } + + dm_start_request(md, rq); + + tio = tio_from_request(rq); + /* Establish tio->ti before queuing work (map_tio_request) */ + tio->ti = ti; + queue_kthread_work(&md->kworker, &tio->work); + BUG_ON(!irqs_disabled()); + } +} + +/* + * Fully initialize a .request_fn request-based queue. + */ +int dm_old_init_request_queue(struct mapped_device *md) +{ + /* Fully initialize the queue */ + if (!blk_init_allocated_queue(md->queue, dm_old_request_fn, NULL)) + return -EINVAL; + + /* disable dm_old_request_fn's merge heuristic by default */ + md->seq_rq_merge_deadline_usecs = 0; + + dm_init_normal_md_queue(md); + blk_queue_softirq_done(md->queue, dm_softirq_done); + blk_queue_prep_rq(md->queue, dm_old_prep_fn); + + /* Initialize the request-based DM worker thread */ + init_kthread_worker(&md->kworker); + md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker, + "kdmwork-%s", dm_device_name(md)); + if (IS_ERR(md->kworker_task)) + return PTR_ERR(md->kworker_task); + + elv_register_queue(md->queue); + + return 0; +} + +static int dm_mq_init_request(void *data, struct request *rq, + unsigned int hctx_idx, unsigned int request_idx, + unsigned int numa_node) +{ + struct mapped_device *md = 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 int 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_MQ_RQ_QUEUE_BUSY; + + 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, rq, md) == DM_MAPIO_REQUEUE) { + /* Undo dm_start_request() before requeuing */ + rq_end_stats(md, rq); + rq_completed(md, rq_data_dir(rq), false); + return BLK_MQ_RQ_QUEUE_BUSY; + } + + return BLK_MQ_RQ_QUEUE_OK; +} + +static struct blk_mq_ops dm_mq_ops = { + .queue_rq = dm_mq_queue_rq, + .map_queue = blk_mq_map_queue, + .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 request_queue *q; + struct dm_target *immutable_tgt; + int err; + + if (!dm_table_all_blk_mq_devices(t)) { + DMERR("request-based dm-mq may only be stacked on blk-mq device(s)"); + return -EINVAL; + } + + 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_SG_MERGE; + 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; + + q = blk_mq_init_allocated_queue(md->tag_set, md->queue); + if (IS_ERR(q)) { + err = PTR_ERR(q); + goto out_tag_set; + } + dm_init_md_queue(md); + + /* backfill 'mq' sysfs registration normally done in blk_register_queue */ + blk_mq_register_disk(md->disk); + + return 0; + +out_tag_set: + blk_mq_free_tag_set(md->tag_set); +out_kfree_tag_set: + kfree(md->tag_set); + + 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); + } +} + +module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"); + +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"); |