kernel_optimize_test/drivers/md/dm-rq.h
Mike Snitzer e83068a5fa dm mpath: add optional "queue_mode" feature
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>
2016-06-10 15:16:02 -04:00

65 lines
1.6 KiB
C

/*
* Internal header file for device mapper
*
* Copyright (C) 2016 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
#ifndef DM_RQ_INTERNAL_H
#define DM_RQ_INTERNAL_H
#include <linux/bio.h>
#include <linux/kthread.h>
#include "dm-stats.h"
struct mapped_device;
/*
* One of these is allocated per request.
*/
struct dm_rq_target_io {
struct mapped_device *md;
struct dm_target *ti;
struct request *orig, *clone;
struct kthread_work work;
int error;
union map_info info;
struct dm_stats_aux stats_aux;
unsigned long duration_jiffies;
unsigned n_sectors;
};
/*
* For request-based dm - the bio clones we allocate are embedded in these
* structs.
*
* We allocate these with bio_alloc_bioset, using the front_pad parameter when
* the bioset is created - this means the bio has to come at the end of the
* struct.
*/
struct dm_rq_clone_bio_info {
struct bio *orig;
struct dm_rq_target_io *tio;
struct bio clone;
};
bool dm_use_blk_mq_default(void);
bool dm_use_blk_mq(struct mapped_device *md);
int dm_old_init_request_queue(struct mapped_device *md);
int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t);
void dm_mq_cleanup_mapped_device(struct mapped_device *md);
void dm_start_queue(struct request_queue *q);
void dm_stop_queue(struct request_queue *q);
unsigned dm_get_reserved_rq_based_ios(void);
ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf);
ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
const char *buf, size_t count);
#endif