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 22 struct 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 */ 31 struct mapped_device { 32 struct srcu_struct io_barrier; 33 struct mutex suspend_lock; 34 35 /* 36 * The current mapping (struct dm_table *). 37 * Use dm_get_live_table{_fast} or take suspend_lock for 38 * dereference. 39 */ 40 void __rcu *map; 41 42 struct list_head table_devices; 43 struct mutex table_devices_lock; 44 45 unsigned long flags; 46 47 struct request_queue *queue; 48 int numa_node_id; 49 50 enum dm_queue_mode type; 51 /* Protect queue and type against concurrent access. */ 52 struct mutex type_lock; 53 54 atomic_t holders; 55 atomic_t open_count; 56 57 struct dm_target *immutable_target; 58 struct target_type *immutable_target_type; 59 60 struct gendisk *disk; 61 struct dax_device *dax_dev; 62 char name[16]; 63 64 void *interface_ptr; 65 66 /* 67 * A list of ios that arrived while we were suspended. 68 */ 69 atomic_t pending[2]; 70 wait_queue_head_t wait; 71 struct work_struct work; 72 spinlock_t deferred_lock; 73 struct bio_list deferred; 74 75 /* 76 * Event handling. 77 */ 78 wait_queue_head_t eventq; 79 atomic_t event_nr; 80 atomic_t uevent_seq; 81 struct list_head uevent_list; 82 spinlock_t uevent_lock; /* Protect access to uevent_list */ 83 84 /* the number of internal suspends */ 85 unsigned internal_suspend_count; 86 87 /* 88 * Processing queue (flush) 89 */ 90 struct workqueue_struct *wq; 91 92 /* 93 * io objects are allocated from here. 94 */ 95 mempool_t *io_pool; 96 97 struct bio_set *bs; 98 99 /* 100 * freeze/thaw support require holding onto a super block 101 */ 102 struct super_block *frozen_sb; 103 104 /* forced geometry settings */ 105 struct hd_geometry geometry; 106 107 struct block_device *bdev; 108 109 /* kobject and completion */ 110 struct dm_kobject_holder kobj_holder; 111 112 /* zero-length flush that will be cloned and submitted to targets */ 113 struct bio flush_bio; 114 115 struct dm_stats stats; 116 117 struct kthread_worker kworker; 118 struct task_struct *kworker_task; 119 120 /* for request-based merge heuristic in dm_request_fn() */ 121 unsigned seq_rq_merge_deadline_usecs; 122 int last_rq_rw; 123 sector_t last_rq_pos; 124 ktime_t last_rq_start_time; 125 126 /* for blk-mq request-based DM support */ 127 struct blk_mq_tag_set *tag_set; 128 bool use_blk_mq:1; 129 bool init_tio_pdu:1; 130 }; 131 132 void dm_init_md_queue(struct mapped_device *md); 133 void dm_init_normal_md_queue(struct mapped_device *md); 134 int md_in_flight(struct mapped_device *md); 135 void disable_write_same(struct mapped_device *md); 136 void disable_write_zeroes(struct mapped_device *md); 137 138 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj) 139 { 140 return &container_of(kobj, struct dm_kobject_holder, kobj)->completion; 141 } 142 143 unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max); 144 145 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen) 146 { 147 return !maxlen || strlen(result) + 1 >= maxlen; 148 } 149 150 extern atomic_t dm_global_event_nr; 151 extern wait_queue_head_t dm_global_eventq; 152 void dm_issue_global_event(void); 153 154 #endif 155