7211aef86f
For a zoned block device using mq-deadline, if a write request for a
zone is received while another write was already dispatched for the same
zone, dd_dispatch_request() will return NULL and the newly inserted
write request is kept in the scheduler queue waiting for the ongoing
zone write to complete. With this behavior, when no other request has
been dispatched, rq_list in blk_mq_sched_dispatch_requests() is empty
and blk_mq_sched_mark_restart_hctx() not called. This in turn leads to
__blk_mq_free_request() call of blk_mq_sched_restart() to not run the
queue when the already dispatched write request completes. The newly
dispatched request stays stuck in the scheduler queue until eventually
another request is submitted.
This problem does not affect SCSI disk as the SCSI stack handles queue
restart on request completion. However, this problem is can be triggered
the nullblk driver with zoned mode enabled.
Fix this by always requesting a queue restart in dd_dispatch_request()
if no request was dispatched while WRITE requests are queued.
Fixes: 5700f69178 ("mq-deadline: Introduce zone locking support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Add missing export of blk_mq_sched_restart()
Signed-off-by: Jens Axboe <axboe@kernel.dk>
94 lines
2.6 KiB
C
94 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef BLK_MQ_SCHED_H
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#define BLK_MQ_SCHED_H
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#include "blk-mq.h"
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#include "blk-mq-tag.h"
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void blk_mq_sched_free_hctx_data(struct request_queue *q,
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void (*exit)(struct blk_mq_hw_ctx *));
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void blk_mq_sched_assign_ioc(struct request *rq);
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void blk_mq_sched_request_inserted(struct request *rq);
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bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
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struct request **merged_request);
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bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio);
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bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq);
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void blk_mq_sched_mark_restart_hctx(struct blk_mq_hw_ctx *hctx);
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void blk_mq_sched_restart(struct blk_mq_hw_ctx *hctx);
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void blk_mq_sched_insert_request(struct request *rq, bool at_head,
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bool run_queue, bool async);
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void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
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struct blk_mq_ctx *ctx,
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struct list_head *list, bool run_queue_async);
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void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx);
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int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e);
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void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e);
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static inline bool
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blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
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{
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if (blk_queue_nomerges(q) || !bio_mergeable(bio))
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return false;
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return __blk_mq_sched_bio_merge(q, bio);
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}
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static inline bool
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blk_mq_sched_allow_merge(struct request_queue *q, struct request *rq,
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struct bio *bio)
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{
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struct elevator_queue *e = q->elevator;
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if (e && e->type->ops.allow_merge)
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return e->type->ops.allow_merge(q, rq, bio);
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return true;
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}
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static inline void blk_mq_sched_completed_request(struct request *rq, u64 now)
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{
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struct elevator_queue *e = rq->q->elevator;
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if (e && e->type->ops.completed_request)
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e->type->ops.completed_request(rq, now);
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}
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static inline void blk_mq_sched_started_request(struct request *rq)
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{
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struct request_queue *q = rq->q;
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struct elevator_queue *e = q->elevator;
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if (e && e->type->ops.started_request)
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e->type->ops.started_request(rq);
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}
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static inline void blk_mq_sched_requeue_request(struct request *rq)
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{
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struct request_queue *q = rq->q;
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struct elevator_queue *e = q->elevator;
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if (e && e->type->ops.requeue_request)
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e->type->ops.requeue_request(rq);
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}
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static inline bool blk_mq_sched_has_work(struct blk_mq_hw_ctx *hctx)
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{
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struct elevator_queue *e = hctx->queue->elevator;
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if (e && e->type->ops.has_work)
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return e->type->ops.has_work(hctx);
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return false;
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}
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static inline bool blk_mq_sched_needs_restart(struct blk_mq_hw_ctx *hctx)
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{
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return test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
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}
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#endif
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