e4d750c977
If we end up doing a request-to-request merge when we have completed a bio-to-request merge, we free the request from deep down in that path. For blk-mq-sched, the merge path has to hold the appropriate lock, but we don't need it for freeing the request. And in fact holding the lock is problematic, since we are now calling the mq sched put_rq_private() hook with the lock held. Other call paths do not hold this lock. Fix this inconsistency by ensuring that the caller frees a merged request. Then we can do it outside of the lock, making it both more efficient and fixing the blk-mq-sched problem of invoking parts of the scheduler with an unknown lock state. Reported-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Omar Sandoval <osandov@fb.com>
143 lines
4 KiB
C
143 lines
4 KiB
C
#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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int blk_mq_sched_init_hctx_data(struct request_queue *q, size_t size,
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int (*init)(struct blk_mq_hw_ctx *),
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void (*exit)(struct blk_mq_hw_ctx *));
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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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struct request *blk_mq_sched_get_request(struct request_queue *q, struct bio *bio, unsigned int op, struct blk_mq_alloc_data *data);
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void blk_mq_sched_put_request(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_restart_queues(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, bool can_block);
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void blk_mq_sched_insert_requests(struct request_queue *q,
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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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void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
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struct list_head *rq_list,
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struct request *(*get_rq)(struct blk_mq_hw_ctx *));
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int blk_mq_sched_setup(struct request_queue *q);
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void blk_mq_sched_teardown(struct request_queue *q);
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int blk_mq_sched_init(struct request_queue *q);
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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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struct elevator_queue *e = q->elevator;
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if (!e || 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 int blk_mq_sched_get_rq_priv(struct request_queue *q,
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struct request *rq)
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{
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struct elevator_queue *e = q->elevator;
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if (e && e->type->ops.mq.get_rq_priv)
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return e->type->ops.mq.get_rq_priv(q, rq);
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return 0;
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}
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static inline void blk_mq_sched_put_rq_priv(struct request_queue *q,
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struct request *rq)
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{
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struct elevator_queue *e = q->elevator;
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if (e && e->type->ops.mq.put_rq_priv)
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e->type->ops.mq.put_rq_priv(q, rq);
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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.mq.allow_merge)
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return e->type->ops.mq.allow_merge(q, rq, bio);
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return true;
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}
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static inline void
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blk_mq_sched_completed_request(struct blk_mq_hw_ctx *hctx, struct request *rq)
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{
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struct elevator_queue *e = hctx->queue->elevator;
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if (e && e->type->ops.mq.completed_request)
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e->type->ops.mq.completed_request(hctx, rq);
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BUG_ON(rq->internal_tag == -1);
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blk_mq_put_tag(hctx, hctx->sched_tags, rq->mq_ctx, rq->internal_tag);
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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.mq.started_request)
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e->type->ops.mq.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.mq.requeue_request)
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e->type->ops.mq.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.mq.has_work)
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return e->type->ops.mq.has_work(hctx);
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return false;
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}
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static inline void blk_mq_sched_mark_restart(struct blk_mq_hw_ctx *hctx)
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{
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if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) {
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set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state);
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if (hctx->flags & BLK_MQ_F_TAG_SHARED) {
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struct request_queue *q = hctx->queue;
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if (!test_bit(QUEUE_FLAG_RESTART, &q->queue_flags))
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set_bit(QUEUE_FLAG_RESTART, &q->queue_flags);
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}
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}
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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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