2 * Internal header file _only_ for device mapper core
4 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
6 * This file is released under the LGPL.
9 #ifndef DM_CORE_INTERNAL_H
10 #define DM_CORE_INTERNAL_H
12 #include <linux/kthread.h>
13 #include <linux/ktime.h>
14 #include <linux/blk-mq.h>
16 #include <trace/events/block.h>
20 #define DM_RESERVED_MAX_IOS 1024
22 struct dm_kobject_holder {
24 struct completion completion;
28 * DM core internal structure that used directly by dm.c and dm-rq.c
29 * DM targets must _not_ deference a mapped_device to directly access its members!
31 struct mapped_device {
32 struct mutex suspend_lock;
35 * The current mapping (struct dm_table *).
36 * Use dm_get_live_table{_fast} or take suspend_lock for
41 struct list_head table_devices;
42 struct mutex table_devices_lock;
46 struct request_queue *queue;
50 /* Protect queue and type against concurrent access. */
51 struct mutex type_lock;
56 struct dm_target *immutable_target;
57 struct target_type *immutable_target_type;
65 * A list of ios that arrived while we were suspended.
68 wait_queue_head_t wait;
69 struct work_struct work;
70 spinlock_t deferred_lock;
71 struct bio_list deferred;
76 wait_queue_head_t eventq;
79 struct list_head uevent_list;
80 spinlock_t uevent_lock; /* Protect access to uevent_list */
82 /* the number of internal suspends */
83 unsigned internal_suspend_count;
86 * Processing queue (flush)
88 struct workqueue_struct *wq;
91 * io objects are allocated from here.
99 * freeze/thaw support require holding onto a super block
101 struct super_block *frozen_sb;
103 /* forced geometry settings */
104 struct hd_geometry geometry;
106 struct block_device *bdev;
108 /* kobject and completion */
109 struct dm_kobject_holder kobj_holder;
111 /* zero-length flush that will be cloned and submitted to targets */
112 struct bio flush_bio;
114 struct dm_stats stats;
116 struct kthread_worker kworker;
117 struct task_struct *kworker_task;
119 /* for request-based merge heuristic in dm_request_fn() */
120 unsigned seq_rq_merge_deadline_usecs;
122 sector_t last_rq_pos;
123 ktime_t last_rq_start_time;
125 /* for blk-mq request-based DM support */
126 struct blk_mq_tag_set *tag_set;
130 struct srcu_struct io_barrier;
133 void dm_init_md_queue(struct mapped_device *md);
134 void dm_init_normal_md_queue(struct mapped_device *md);
135 int md_in_flight(struct mapped_device *md);
136 void disable_write_same(struct mapped_device *md);
138 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
140 return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
143 unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);
145 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
147 return !maxlen || strlen(result) + 1 >= maxlen;