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![Damien Le Moal](/assets/img/avatar_default.png)
When elevator_init_mq() is called from blk_mq_init_allocated_queue(), the only information known about the device is the number of hardware queues as the block device scan by the device driver is not completed yet for most drivers. The device type and elevator required features are not set yet, preventing to correctly select the default elevator most suitable for the device. This currently affects all multi-queue zoned block devices which default to the "none" elevator instead of the required "mq-deadline" elevator. These drives currently include host-managed SMR disks connected to a smartpqi HBA and null_blk block devices with zoned mode enabled. Upcoming NVMe Zoned Namespace devices will also be affected. Fix this by adding the boolean elevator_init argument to blk_mq_init_allocated_queue() to control the execution of elevator_init_mq(). Two cases exist: 1) elevator_init = false is used for calls to blk_mq_init_allocated_queue() within blk_mq_init_queue(). In this case, a call to elevator_init_mq() is added to __device_add_disk(), resulting in the delayed initialization of the queue elevator after the device driver finished probing the device information. This effectively allows elevator_init_mq() access to more information about the device. 2) elevator_init = true preserves the current behavior of initializing the elevator directly from blk_mq_init_allocated_queue(). This case is used for the special request based DM devices where the device gendisk is created before the queue initialization and device information (e.g. queue limits) is already known when the queue initialization is executed. Additionally, to make sure that the elevator initialization is never done while requests are in-flight (there should be none when the device driver calls device_add_disk()), freeze and quiesce the device request queue before calling blk_mq_init_sched() in elevator_init_mq(). Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
602 lines
15 KiB
C
602 lines
15 KiB
C
/*
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* Copyright (C) 2016 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include "dm-core.h"
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#include "dm-rq.h"
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#include <linux/elevator.h> /* for rq_end_sector() */
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#include <linux/blk-mq.h>
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#define DM_MSG_PREFIX "core-rq"
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/*
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* One of these is allocated per request.
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*/
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struct dm_rq_target_io {
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struct mapped_device *md;
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struct dm_target *ti;
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struct request *orig, *clone;
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struct kthread_work work;
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blk_status_t error;
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union map_info info;
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struct dm_stats_aux stats_aux;
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unsigned long duration_jiffies;
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unsigned n_sectors;
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unsigned completed;
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};
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#define DM_MQ_NR_HW_QUEUES 1
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#define DM_MQ_QUEUE_DEPTH 2048
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static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
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static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
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/*
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* Request-based DM's mempools' reserved IOs set by the user.
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*/
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#define RESERVED_REQUEST_BASED_IOS 256
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static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
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unsigned dm_get_reserved_rq_based_ios(void)
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{
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return __dm_get_module_param(&reserved_rq_based_ios,
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RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);
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}
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EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
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static unsigned dm_get_blk_mq_nr_hw_queues(void)
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{
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return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
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}
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static unsigned dm_get_blk_mq_queue_depth(void)
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{
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return __dm_get_module_param(&dm_mq_queue_depth,
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DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
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}
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int dm_request_based(struct mapped_device *md)
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{
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return queue_is_mq(md->queue);
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}
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void dm_start_queue(struct request_queue *q)
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{
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blk_mq_unquiesce_queue(q);
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blk_mq_kick_requeue_list(q);
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}
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void dm_stop_queue(struct request_queue *q)
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{
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if (blk_mq_queue_stopped(q))
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return;
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blk_mq_quiesce_queue(q);
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}
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/*
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* Partial completion handling for request-based dm
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*/
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static void end_clone_bio(struct bio *clone)
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{
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struct dm_rq_clone_bio_info *info =
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container_of(clone, struct dm_rq_clone_bio_info, clone);
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struct dm_rq_target_io *tio = info->tio;
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unsigned int nr_bytes = info->orig->bi_iter.bi_size;
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blk_status_t error = clone->bi_status;
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bool is_last = !clone->bi_next;
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bio_put(clone);
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if (tio->error)
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/*
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* An error has already been detected on the request.
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* Once error occurred, just let clone->end_io() handle
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* the remainder.
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*/
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return;
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else if (error) {
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/*
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* Don't notice the error to the upper layer yet.
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* The error handling decision is made by the target driver,
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* when the request is completed.
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*/
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tio->error = error;
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goto exit;
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}
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/*
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* I/O for the bio successfully completed.
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* Notice the data completion to the upper layer.
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*/
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tio->completed += nr_bytes;
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/*
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* Update the original request.
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* Do not use blk_mq_end_request() here, because it may complete
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* the original request before the clone, and break the ordering.
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*/
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if (is_last)
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exit:
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blk_update_request(tio->orig, BLK_STS_OK, tio->completed);
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}
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static struct dm_rq_target_io *tio_from_request(struct request *rq)
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{
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return blk_mq_rq_to_pdu(rq);
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}
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static void rq_end_stats(struct mapped_device *md, struct request *orig)
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{
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if (unlikely(dm_stats_used(&md->stats))) {
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struct dm_rq_target_io *tio = tio_from_request(orig);
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tio->duration_jiffies = jiffies - tio->duration_jiffies;
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dm_stats_account_io(&md->stats, rq_data_dir(orig),
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blk_rq_pos(orig), tio->n_sectors, true,
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tio->duration_jiffies, &tio->stats_aux);
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}
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}
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/*
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* Don't touch any member of the md after calling this function because
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* the md may be freed in dm_put() at the end of this function.
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* Or do dm_get() before calling this function and dm_put() later.
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*/
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static void rq_completed(struct mapped_device *md)
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{
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/* nudge anyone waiting on suspend queue */
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if (unlikely(wq_has_sleeper(&md->wait)))
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wake_up(&md->wait);
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/*
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* dm_put() must be at the end of this function. See the comment above
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*/
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dm_put(md);
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}
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/*
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* Complete the clone and the original request.
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* Must be called without clone's queue lock held,
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* see end_clone_request() for more details.
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*/
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static void dm_end_request(struct request *clone, blk_status_t error)
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{
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struct dm_rq_target_io *tio = clone->end_io_data;
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struct mapped_device *md = tio->md;
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struct request *rq = tio->orig;
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blk_rq_unprep_clone(clone);
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tio->ti->type->release_clone_rq(clone, NULL);
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rq_end_stats(md, rq);
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blk_mq_end_request(rq, error);
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rq_completed(md);
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}
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static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)
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{
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blk_mq_delay_kick_requeue_list(q, msecs);
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}
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void dm_mq_kick_requeue_list(struct mapped_device *md)
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{
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__dm_mq_kick_requeue_list(dm_get_md_queue(md), 0);
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}
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EXPORT_SYMBOL(dm_mq_kick_requeue_list);
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static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
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{
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blk_mq_requeue_request(rq, false);
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__dm_mq_kick_requeue_list(rq->q, msecs);
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}
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static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue)
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{
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struct mapped_device *md = tio->md;
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struct request *rq = tio->orig;
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unsigned long delay_ms = delay_requeue ? 100 : 0;
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rq_end_stats(md, rq);
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if (tio->clone) {
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blk_rq_unprep_clone(tio->clone);
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tio->ti->type->release_clone_rq(tio->clone, NULL);
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}
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dm_mq_delay_requeue_request(rq, delay_ms);
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rq_completed(md);
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}
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static void dm_done(struct request *clone, blk_status_t error, bool mapped)
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{
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int r = DM_ENDIO_DONE;
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struct dm_rq_target_io *tio = clone->end_io_data;
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dm_request_endio_fn rq_end_io = NULL;
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if (tio->ti) {
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rq_end_io = tio->ti->type->rq_end_io;
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if (mapped && rq_end_io)
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r = rq_end_io(tio->ti, clone, error, &tio->info);
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}
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if (unlikely(error == BLK_STS_TARGET)) {
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if (req_op(clone) == REQ_OP_DISCARD &&
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!clone->q->limits.max_discard_sectors)
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disable_discard(tio->md);
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else if (req_op(clone) == REQ_OP_WRITE_SAME &&
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!clone->q->limits.max_write_same_sectors)
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disable_write_same(tio->md);
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else if (req_op(clone) == REQ_OP_WRITE_ZEROES &&
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!clone->q->limits.max_write_zeroes_sectors)
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disable_write_zeroes(tio->md);
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}
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switch (r) {
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case DM_ENDIO_DONE:
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/* The target wants to complete the I/O */
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dm_end_request(clone, error);
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break;
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case DM_ENDIO_INCOMPLETE:
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/* The target will handle the I/O */
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return;
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case DM_ENDIO_REQUEUE:
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/* The target wants to requeue the I/O */
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dm_requeue_original_request(tio, false);
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break;
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case DM_ENDIO_DELAY_REQUEUE:
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/* The target wants to requeue the I/O after a delay */
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dm_requeue_original_request(tio, true);
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break;
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default:
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DMWARN("unimplemented target endio return value: %d", r);
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BUG();
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}
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}
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/*
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* Request completion handler for request-based dm
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*/
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static void dm_softirq_done(struct request *rq)
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{
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bool mapped = true;
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struct dm_rq_target_io *tio = tio_from_request(rq);
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struct request *clone = tio->clone;
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if (!clone) {
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struct mapped_device *md = tio->md;
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rq_end_stats(md, rq);
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blk_mq_end_request(rq, tio->error);
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rq_completed(md);
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return;
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}
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if (rq->rq_flags & RQF_FAILED)
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mapped = false;
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dm_done(clone, tio->error, mapped);
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}
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/*
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* Complete the clone and the original request with the error status
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* through softirq context.
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*/
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static void dm_complete_request(struct request *rq, blk_status_t error)
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{
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struct dm_rq_target_io *tio = tio_from_request(rq);
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tio->error = error;
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blk_mq_complete_request(rq);
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}
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/*
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* Complete the not-mapped clone and the original request with the error status
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* through softirq context.
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* Target's rq_end_io() function isn't called.
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* This may be used when the target's clone_and_map_rq() function fails.
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*/
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static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
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{
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rq->rq_flags |= RQF_FAILED;
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dm_complete_request(rq, error);
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}
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static void end_clone_request(struct request *clone, blk_status_t error)
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{
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struct dm_rq_target_io *tio = clone->end_io_data;
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dm_complete_request(tio->orig, error);
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}
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static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
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{
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blk_status_t r;
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if (blk_queue_io_stat(clone->q))
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clone->rq_flags |= RQF_IO_STAT;
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clone->start_time_ns = ktime_get_ns();
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r = blk_insert_cloned_request(clone->q, clone);
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if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE)
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/* must complete clone in terms of original request */
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dm_complete_request(rq, r);
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return r;
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}
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static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
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void *data)
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{
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struct dm_rq_target_io *tio = data;
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struct dm_rq_clone_bio_info *info =
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container_of(bio, struct dm_rq_clone_bio_info, clone);
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info->orig = bio_orig;
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info->tio = tio;
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bio->bi_end_io = end_clone_bio;
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return 0;
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}
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static int setup_clone(struct request *clone, struct request *rq,
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struct dm_rq_target_io *tio, gfp_t gfp_mask)
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{
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int r;
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r = blk_rq_prep_clone(clone, rq, &tio->md->bs, gfp_mask,
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dm_rq_bio_constructor, tio);
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if (r)
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return r;
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clone->end_io = end_clone_request;
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clone->end_io_data = tio;
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tio->clone = clone;
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return 0;
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}
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static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
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struct mapped_device *md)
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{
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tio->md = md;
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tio->ti = NULL;
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tio->clone = NULL;
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tio->orig = rq;
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tio->error = 0;
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tio->completed = 0;
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/*
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* Avoid initializing info for blk-mq; it passes
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* target-specific data through info.ptr
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* (see: dm_mq_init_request)
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*/
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if (!md->init_tio_pdu)
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memset(&tio->info, 0, sizeof(tio->info));
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}
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/*
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* Returns:
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* DM_MAPIO_* : the request has been processed as indicated
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* DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
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* < 0 : the request was completed due to failure
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*/
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static int map_request(struct dm_rq_target_io *tio)
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{
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int r;
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struct dm_target *ti = tio->ti;
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struct mapped_device *md = tio->md;
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struct request *rq = tio->orig;
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struct request *clone = NULL;
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blk_status_t ret;
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r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
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switch (r) {
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case DM_MAPIO_SUBMITTED:
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/* The target has taken the I/O to submit by itself later */
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break;
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case DM_MAPIO_REMAPPED:
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if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
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/* -ENOMEM */
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ti->type->release_clone_rq(clone, &tio->info);
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return DM_MAPIO_REQUEUE;
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}
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/* The target has remapped the I/O so dispatch it */
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trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
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blk_rq_pos(rq));
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ret = dm_dispatch_clone_request(clone, rq);
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if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
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blk_rq_unprep_clone(clone);
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blk_mq_cleanup_rq(clone);
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tio->ti->type->release_clone_rq(clone, &tio->info);
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tio->clone = NULL;
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return DM_MAPIO_REQUEUE;
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}
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break;
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case DM_MAPIO_REQUEUE:
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/* The target wants to requeue the I/O */
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break;
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case DM_MAPIO_DELAY_REQUEUE:
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/* The target wants to requeue the I/O after a delay */
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dm_requeue_original_request(tio, true);
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break;
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case DM_MAPIO_KILL:
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/* The target wants to complete the I/O */
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dm_kill_unmapped_request(rq, BLK_STS_IOERR);
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break;
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default:
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DMWARN("unimplemented target map return value: %d", r);
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BUG();
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}
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return r;
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}
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/* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */
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ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
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{
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return sprintf(buf, "%u\n", 0);
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}
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ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
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const char *buf, size_t count)
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{
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return count;
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}
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static void dm_start_request(struct mapped_device *md, struct request *orig)
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{
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blk_mq_start_request(orig);
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if (unlikely(dm_stats_used(&md->stats))) {
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struct dm_rq_target_io *tio = tio_from_request(orig);
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tio->duration_jiffies = jiffies;
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tio->n_sectors = blk_rq_sectors(orig);
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dm_stats_account_io(&md->stats, rq_data_dir(orig),
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blk_rq_pos(orig), tio->n_sectors, false, 0,
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&tio->stats_aux);
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}
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/*
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* Hold the md reference here for the in-flight I/O.
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* We can't rely on the reference count by device opener,
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* because the device may be closed during the request completion
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* when all bios are completed.
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* See the comment in rq_completed() too.
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*/
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dm_get(md);
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}
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static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
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unsigned int hctx_idx, unsigned int numa_node)
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{
|
|
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 request_queue *q;
|
|
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;
|
|
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, true);
|
|
if (IS_ERR(q)) {
|
|
err = PTR_ERR(q);
|
|
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);
|
|
|
|
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");
|
|
|
|
/* 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");
|