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![Mike Snitzer](/assets/img/avatar_default.png)
Allow a user to specify an optional feature 'queue_mode <mode>' where <mode> may be "bio", "rq" or "mq" -- which corresponds to bio-based, request_fn rq-based, and blk-mq rq-based respectively. If the queue_mode feature isn't specified the default for the "multipath" target is still "rq" but if dm_mod.use_blk_mq is set to Y it'll default to mode "mq". This new queue_mode feature introduces the ability for each multipath device to have its own queue_mode (whereas before this feature all multipath devices effectively had to have the same queue_mode). This commit also goes a long way to eliminate the awkward (ab)use of DM_TYPE_*, the associated filter_md_type() and other relatively fragile and difficult to maintain code. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
64 lines
1.6 KiB
C
64 lines
1.6 KiB
C
/*
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* Internal header file for device mapper
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*
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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 LGPL.
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*/
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#ifndef DM_RQ_INTERNAL_H
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#define DM_RQ_INTERNAL_H
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#include <linux/bio.h>
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#include <linux/kthread.h>
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#include "dm-stats.h"
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struct mapped_device;
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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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int 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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};
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/*
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* For request-based dm - the bio clones we allocate are embedded in these
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* structs.
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*
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* We allocate these with bio_alloc_bioset, using the front_pad parameter when
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* the bioset is created - this means the bio has to come at the end of the
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* struct.
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*/
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struct dm_rq_clone_bio_info {
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struct bio *orig;
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struct dm_rq_target_io *tio;
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struct bio clone;
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};
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bool dm_use_blk_mq_default(void);
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bool dm_use_blk_mq(struct mapped_device *md);
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int dm_old_init_request_queue(struct mapped_device *md);
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int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t);
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void dm_mq_cleanup_mapped_device(struct mapped_device *md);
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void dm_start_queue(struct request_queue *q);
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void dm_stop_queue(struct request_queue *q);
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unsigned dm_get_reserved_rq_based_ios(void);
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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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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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#endif
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