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/genhd.h>
  15 #include <linux/blk-mq.h>
  16
  17 #include <trace/events/block.h>
  18
  19 #include "dm.h"
  20
  21 #define DM_RESERVED_MAX_IOS             1024
  22
  23 struct dm_kobject_holder {
  24         struct kobject kobj;
  25         struct completion completion;
  26 };
  27
  28 /*
  29  * DM core internal structures used directly by dm.c, dm-rq.c and dm-table.c.
  30  * DM targets must _not_ deference a mapped_device or dm_table to directly
  31  * access their members!
  32  */
  33
  34 struct mapped_device {
  35         struct mutex suspend_lock;
  36
  37         struct mutex table_devices_lock;
  38         struct list_head table_devices;
  39
  40         /*
  41          * The current mapping (struct dm_table *).
  42          * Use dm_get_live_table{_fast} or take suspend_lock for
  43          * dereference.
  44          */
  45         void __rcu *map;
  46
  47         unsigned long flags;
  48
  49         /* Protect queue and type against concurrent access. */
  50         struct mutex type_lock;
  51         enum dm_queue_mode type;
  52
  53         int numa_node_id;
  54         struct request_queue *queue;
  55
  56         atomic_t holders;
  57         atomic_t open_count;
  58
  59         struct dm_target *immutable_target;
  60         struct target_type *immutable_target_type;
  61
  62         char name[16];
  63         struct gendisk *disk;
  64         struct dax_device *dax_dev;
  65
  66         /*
  67          * A list of ios that arrived while we were suspended.
  68          */
  69         struct work_struct work;
  70         wait_queue_head_t wait;
  71         spinlock_t deferred_lock;
  72         struct bio_list deferred;
  73
  74         void *interface_ptr;
  75
  76         /*
  77          * Event handling.
  78          */
  79         wait_queue_head_t eventq;
  80         atomic_t event_nr;
  81         atomic_t uevent_seq;
  82         struct list_head uevent_list;
  83         spinlock_t uevent_lock; /* Protect access to uevent_list */
  84
  85         /* the number of internal suspends */
  86         unsigned internal_suspend_count;
  87
  88         /*
  89          * io objects are allocated from here.
  90          */
  91         struct bio_set io_bs;
  92         struct bio_set bs;
  93
  94         /*
  95          * Processing queue (flush)
  96          */
  97         struct workqueue_struct *wq;
  98
  99         /* forced geometry settings */
 100         struct hd_geometry geometry;
 101
 102         /* kobject and completion */
 103         struct dm_kobject_holder kobj_holder;
 104
 105         struct dm_stats stats;
 106
 107         /* for blk-mq request-based DM support */
 108         struct blk_mq_tag_set *tag_set;
 109         bool init_tio_pdu:1;
 110
 111         struct srcu_struct io_barrier;
 112 };
 113
 114 void disable_discard(struct mapped_device *md);
 115 void disable_write_same(struct mapped_device *md);
 116 void disable_write_zeroes(struct mapped_device *md);
 117
 118 static inline sector_t dm_get_size(struct mapped_device *md)
 119 {
 120         return get_capacity(md->disk);
 121 }
 122
 123 static inline struct dm_stats *dm_get_stats(struct mapped_device *md)
 124 {
 125         return &md->stats;
 126 }
 127
 128 #define DM_TABLE_MAX_DEPTH 16
 129
 130 struct dm_table {
 131         struct mapped_device *md;
 132         enum dm_queue_mode type;
 133
 134         /* btree table */
 135         unsigned int depth;
 136         unsigned int counts[DM_TABLE_MAX_DEPTH]; /* in nodes */
 137         sector_t *index[DM_TABLE_MAX_DEPTH];
 138
 139         unsigned int num_targets;
 140         unsigned int num_allocated;
 141         sector_t *highs;
 142         struct dm_target *targets;
 143
 144         struct target_type *immutable_target_type;
 145
 146         bool integrity_supported:1;
 147         bool singleton:1;
 148         unsigned integrity_added:1;
 149
 150         /*
 151          * Indicates the rw permissions for the new logical
 152          * device.  This should be a combination of FMODE_READ
 153          * and FMODE_WRITE.
 154          */
 155         fmode_t mode;
 156
 157         /* a list of devices used by this table */
 158         struct list_head devices;
 159
 160         /* events get handed up using this callback */
 161         void (*event_fn)(void *);
 162         void *event_context;
 163
 164         struct dm_md_mempools *mempools;
 165 };
 166
 167 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
 168 {
 169         return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
 170 }
 171
 172 unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);
 173
 174 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
 175 {
 176         return !maxlen || strlen(result) + 1 >= maxlen;
 177 }
 178
 179 extern atomic_t dm_global_event_nr;
 180 extern wait_queue_head_t dm_global_eventq;
 181 void dm_issue_global_event(void);
 182
 183 #endif