LXR linux/drivers/md/dm-core.h

   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_write_same(struct mapped_device *md);
 119void disable_write_zeroes(struct mapped_device *md);
 120
 121static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 122{
 123        return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 124}
 125
 126unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);
 127
 128static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 129{
 130        return !maxlen || strlen(result) + 1 >= maxlen;
 131}
 132
 133extern atomic_t dm_global_event_nr;
 134extern wait_queue_head_t dm_global_eventq;
 135void dm_issue_global_event(void);
 136
 137#endif
 138