1/*
  2 * Internal header file _only_ for device mapper core
  3 *
  4 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
  5 *
  6 * This file is released under the LGPL.
  7 */
  8
  9#ifndef DM_CORE_INTERNAL_H
 10#define DM_CORE_INTERNAL_H
 11
 12#include <linux/kthread.h>
 13#include <linux/ktime.h>
 14#include <linux/blk-mq.h>
 15
 16#include <trace/events/block.h>
 17
 18#include "dm.h"
 19
 20#define DM_RESERVED_MAX_IOS		1024
 21
 22struct dm_kobject_holder {
 23	struct kobject kobj;
 24	struct completion completion;
 25};
 26
 27/*
 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!
 30 */
 31struct mapped_device {
 32	struct mutex suspend_lock;
 33
 34	struct mutex table_devices_lock;
 35	struct list_head table_devices;
 36
 37	/*
 38	 * The current mapping (struct dm_table *).
 39	 * Use dm_get_live_table{_fast} or take suspend_lock for
 40	 * dereference.
 41	 */
 42	void __rcu *map;
 43
 44	unsigned long flags;
 45
 46	/* Protect queue and type against concurrent access. */
 47	struct mutex type_lock;
 48	enum dm_queue_mode type;
 49
 50	int numa_node_id;
 51	struct request_queue *queue;
 52
 53	atomic_t holders;
 54	atomic_t open_count;
 55
 56	struct dm_target *immutable_target;
 57	struct target_type *immutable_target_type;
 58
 59	char name[16];
 60	struct gendisk *disk;
 61	struct dax_device *dax_dev;
 62
 63	/*
 64	 * A list of ios that arrived while we were suspended.
 65	 */
 66	struct work_struct work;
 67	wait_queue_head_t wait;
 68	spinlock_t deferred_lock;
 69	struct bio_list deferred;
 70
 71	void *interface_ptr;
 72
 73	/*
 74	 * Event handling.
 75	 */
 76	wait_queue_head_t eventq;
 77	atomic_t event_nr;
 78	atomic_t uevent_seq;
 79	struct list_head uevent_list;
 80	spinlock_t uevent_lock; /* Protect access to uevent_list */
 81
 82	/* the number of internal suspends */
 83	unsigned internal_suspend_count;
 84
 85	/*
 86	 * io objects are allocated from here.
 87	 */
 88	struct bio_set io_bs;
 89	struct bio_set bs;
 90
 91	/*
 92	 * Processing queue (flush)
 93	 */
 94	struct workqueue_struct *wq;
 95
 96	/*
 97	 * freeze/thaw support require holding onto a super block
 98	 */
 99	struct super_block *frozen_sb;
100
101	/* forced geometry settings */
102	struct hd_geometry geometry;
103
104	/* kobject and completion */
105	struct dm_kobject_holder kobj_holder;
106
107	struct block_device *bdev;
108
109	struct dm_stats stats;
110
111	/* for blk-mq request-based DM support */
112	struct blk_mq_tag_set *tag_set;
113	bool init_tio_pdu:1;
114
115	struct srcu_struct io_barrier;
116};
117
118void disable_discard(struct mapped_device *md);
119void disable_write_same(struct mapped_device *md);
120void disable_write_zeroes(struct mapped_device *md);
121
122static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
123{
124	return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
125}
126
127unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);
128
129static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
130{
131	return !maxlen || strlen(result) + 1 >= maxlen;
132}
133
134extern atomic_t dm_global_event_nr;
135extern wait_queue_head_t dm_global_eventq;
136void dm_issue_global_event(void);
137
138#endif