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 mutex suspend_lock; 33 34 /* 35 * The current mapping (struct dm_table *). 36 * Use dm_get_live_table{_fast} or take suspend_lock for 37 * dereference. 38 */ 39 void __rcu *map; 40 41 struct list_head table_devices; 42 struct mutex table_devices_lock; 43 44 unsigned long flags; 45 46 struct request_queue *queue; 47 int numa_node_id; 48 49 enum dm_queue_mode type; 50 /* Protect queue and type against concurrent access. */ 51 struct mutex type_lock; 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 struct gendisk *disk; 60 struct dax_device *dax_dev; 61 char name[16]; 62 63 void *interface_ptr; 64 65 /* 66 * A list of ios that arrived while we were suspended. 67 */ 68 atomic_t pending[2]; 69 wait_queue_head_t wait; 70 struct work_struct work; 71 spinlock_t deferred_lock; 72 struct bio_list deferred; 73 74 /* 75 * Event handling. 76 */ 77 wait_queue_head_t eventq; 78 atomic_t event_nr; 79 atomic_t uevent_seq; 80 struct list_head uevent_list; 81 spinlock_t uevent_lock; /* Protect access to uevent_list */ 82 83 /* the number of internal suspends */ 84 unsigned internal_suspend_count; 85 86 /* 87 * Processing queue (flush) 88 */ 89 struct workqueue_struct *wq; 90 91 /* 92 * io objects are allocated from here. 93 */ 94 mempool_t *io_pool; 95 96 struct bio_set *bs; 97 98 /* 99 * freeze/thaw support require holding onto a super block 100 */ 101 struct super_block *frozen_sb; 102 103 /* forced geometry settings */ 104 struct hd_geometry geometry; 105 106 struct block_device *bdev; 107 108 /* kobject and completion */ 109 struct dm_kobject_holder kobj_holder; 110 111 /* zero-length flush that will be cloned and submitted to targets */ 112 struct bio flush_bio; 113 114 struct dm_stats stats; 115 116 struct kthread_worker kworker; 117 struct task_struct *kworker_task; 118 119 /* for request-based merge heuristic in dm_request_fn() */ 120 unsigned seq_rq_merge_deadline_usecs; 121 int last_rq_rw; 122 sector_t last_rq_pos; 123 ktime_t last_rq_start_time; 124 125 /* for blk-mq request-based DM support */ 126 struct blk_mq_tag_set *tag_set; 127 bool use_blk_mq:1; 128 bool init_tio_pdu:1; 129 130 struct srcu_struct io_barrier; 131 }; 132 133 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); 137 void disable_write_zeroes(struct mapped_device *md); 138 139 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj) 140 { 141 return &container_of(kobj, struct dm_kobject_holder, kobj)->completion; 142 } 143 144 unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max); 145 146 static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen) 147 { 148 return !maxlen || strlen(result) + 1 >= maxlen; 149 } 150 151 extern atomic_t dm_global_event_nr; 152 extern wait_queue_head_t dm_global_eventq; 153 void dm_issue_global_event(void); 154 155 #endif 156