1 #ifndef BLK_INTERNAL_H 2 #define BLK_INTERNAL_H 3 4 #include <linux/idr.h> 5 6 /* Amount of time in which a process may batch requests */ 7 #define BLK_BATCH_TIME (HZ/50UL) 8 9 /* Number of requests a "batching" process may submit */ 10 #define BLK_BATCH_REQ 32 11 12 extern struct kmem_cache *blk_requestq_cachep; 13 extern struct kmem_cache *request_cachep; 14 extern struct kobj_type blk_queue_ktype; 15 extern struct ida blk_queue_ida; 16 17 static inline void __blk_get_queue(struct request_queue *q) 18 { 19 kobject_get(&q->kobj); 20 } 21 22 int blk_init_rl(struct request_list *rl, struct request_queue *q, 23 gfp_t gfp_mask); 24 void blk_exit_rl(struct request_list *rl); 25 void init_request_from_bio(struct request *req, struct bio *bio); 26 void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 27 struct bio *bio); 28 int blk_rq_append_bio(struct request_queue *q, struct request *rq, 29 struct bio *bio); 30 void blk_queue_bypass_start(struct request_queue *q); 31 void blk_queue_bypass_end(struct request_queue *q); 32 void blk_dequeue_request(struct request *rq); 33 void __blk_queue_free_tags(struct request_queue *q); 34 bool __blk_end_bidi_request(struct request *rq, int error, 35 unsigned int nr_bytes, unsigned int bidi_bytes); 36 37 void blk_rq_timed_out_timer(unsigned long data); 38 void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout, 39 unsigned int *next_set); 40 void __blk_add_timer(struct request *req, struct list_head *timeout_list); 41 void blk_delete_timer(struct request *); 42 void blk_add_timer(struct request *); 43 44 45 bool bio_attempt_front_merge(struct request_queue *q, struct request *req, 46 struct bio *bio); 47 bool bio_attempt_back_merge(struct request_queue *q, struct request *req, 48 struct bio *bio); 49 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, 50 unsigned int *request_count); 51 52 void blk_account_io_start(struct request *req, bool new_io); 53 void blk_account_io_completion(struct request *req, unsigned int bytes); 54 void blk_account_io_done(struct request *req); 55 56 /* 57 * Internal atomic flags for request handling 58 */ 59 enum rq_atomic_flags { 60 REQ_ATOM_COMPLETE = 0, 61 REQ_ATOM_STARTED, 62 }; 63 64 /* 65 * EH timer and IO completion will both attempt to 'grab' the request, make 66 * sure that only one of them succeeds 67 */ 68 static inline int blk_mark_rq_complete(struct request *rq) 69 { 70 return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 71 } 72 73 static inline void blk_clear_rq_complete(struct request *rq) 74 { 75 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); 76 } 77 78 /* 79 * Internal elevator interface 80 */ 81 #define ELV_ON_HASH(rq) hash_hashed(&(rq)->hash) 82 83 void blk_insert_flush(struct request *rq); 84 void blk_abort_flushes(struct request_queue *q); 85 86 static inline struct request *__elv_next_request(struct request_queue *q) 87 { 88 struct request *rq; 89 90 while (1) { 91 if (!list_empty(&q->queue_head)) { 92 rq = list_entry_rq(q->queue_head.next); 93 return rq; 94 } 95 96 /* 97 * Flush request is running and flush request isn't queueable 98 * in the drive, we can hold the queue till flush request is 99 * finished. Even we don't do this, driver can't dispatch next 100 * requests and will requeue them. And this can improve 101 * throughput too. For example, we have request flush1, write1, 102 * flush 2. flush1 is dispatched, then queue is hold, write1 103 * isn't inserted to queue. After flush1 is finished, flush2 104 * will be dispatched. Since disk cache is already clean, 105 * flush2 will be finished very soon, so looks like flush2 is 106 * folded to flush1. 107 * Since the queue is hold, a flag is set to indicate the queue 108 * should be restarted later. Please see flush_end_io() for 109 * details. 110 */ 111 if (q->flush_pending_idx != q->flush_running_idx && 112 !queue_flush_queueable(q)) { 113 q->flush_queue_delayed = 1; 114 return NULL; 115 } 116 if (unlikely(blk_queue_dying(q)) || 117 !q->elevator->type->ops.elevator_dispatch_fn(q, 0)) 118 return NULL; 119 } 120 } 121 122 static inline void elv_activate_rq(struct request_queue *q, struct request *rq) 123 { 124 struct elevator_queue *e = q->elevator; 125 126 if (e->type->ops.elevator_activate_req_fn) 127 e->type->ops.elevator_activate_req_fn(q, rq); 128 } 129 130 static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq) 131 { 132 struct elevator_queue *e = q->elevator; 133 134 if (e->type->ops.elevator_deactivate_req_fn) 135 e->type->ops.elevator_deactivate_req_fn(q, rq); 136 } 137 138 #ifdef CONFIG_FAIL_IO_TIMEOUT 139 int blk_should_fake_timeout(struct request_queue *); 140 ssize_t part_timeout_show(struct device *, struct device_attribute *, char *); 141 ssize_t part_timeout_store(struct device *, struct device_attribute *, 142 const char *, size_t); 143 #else 144 static inline int blk_should_fake_timeout(struct request_queue *q) 145 { 146 return 0; 147 } 148 #endif 149 150 int ll_back_merge_fn(struct request_queue *q, struct request *req, 151 struct bio *bio); 152 int ll_front_merge_fn(struct request_queue *q, struct request *req, 153 struct bio *bio); 154 int attempt_back_merge(struct request_queue *q, struct request *rq); 155 int attempt_front_merge(struct request_queue *q, struct request *rq); 156 int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 157 struct request *next); 158 void blk_recalc_rq_segments(struct request *rq); 159 void blk_rq_set_mixed_merge(struct request *rq); 160 bool blk_rq_merge_ok(struct request *rq, struct bio *bio); 161 int blk_try_merge(struct request *rq, struct bio *bio); 162 163 void blk_queue_congestion_threshold(struct request_queue *q); 164 165 void __blk_run_queue_uncond(struct request_queue *q); 166 167 int blk_dev_init(void); 168 169 170 /* 171 * Return the threshold (number of used requests) at which the queue is 172 * considered to be congested. It include a little hysteresis to keep the 173 * context switch rate down. 174 */ 175 static inline int queue_congestion_on_threshold(struct request_queue *q) 176 { 177 return q->nr_congestion_on; 178 } 179 180 /* 181 * The threshold at which a queue is considered to be uncongested 182 */ 183 static inline int queue_congestion_off_threshold(struct request_queue *q) 184 { 185 return q->nr_congestion_off; 186 } 187 188 /* 189 * Contribute to IO statistics IFF: 190 * 191 * a) it's attached to a gendisk, and 192 * b) the queue had IO stats enabled when this request was started, and 193 * c) it's a file system request 194 */ 195 static inline int blk_do_io_stat(struct request *rq) 196 { 197 return rq->rq_disk && 198 (rq->cmd_flags & REQ_IO_STAT) && 199 (rq->cmd_type == REQ_TYPE_FS); 200 } 201 202 /* 203 * Internal io_context interface 204 */ 205 void get_io_context(struct io_context *ioc); 206 struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q); 207 struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q, 208 gfp_t gfp_mask); 209 void ioc_clear_queue(struct request_queue *q); 210 211 int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node); 212 213 /** 214 * create_io_context - try to create task->io_context 215 * @gfp_mask: allocation mask 216 * @node: allocation node 217 * 218 * If %current->io_context is %NULL, allocate a new io_context and install 219 * it. Returns the current %current->io_context which may be %NULL if 220 * allocation failed. 221 * 222 * Note that this function can't be called with IRQ disabled because 223 * task_lock which protects %current->io_context is IRQ-unsafe. 224 */ 225 static inline struct io_context *create_io_context(gfp_t gfp_mask, int node) 226 { 227 WARN_ON_ONCE(irqs_disabled()); 228 if (unlikely(!current->io_context)) 229 create_task_io_context(current, gfp_mask, node); 230 return current->io_context; 231 } 232 233 /* 234 * Internal throttling interface 235 */ 236 #ifdef CONFIG_BLK_DEV_THROTTLING 237 extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio); 238 extern void blk_throtl_drain(struct request_queue *q); 239 extern int blk_throtl_init(struct request_queue *q); 240 extern void blk_throtl_exit(struct request_queue *q); 241 #else /* CONFIG_BLK_DEV_THROTTLING */ 242 static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio) 243 { 244 return false; 245 } 246 static inline void blk_throtl_drain(struct request_queue *q) { } 247 static inline int blk_throtl_init(struct request_queue *q) { return 0; } 248 static inline void blk_throtl_exit(struct request_queue *q) { } 249 #endif /* CONFIG_BLK_DEV_THROTTLING */ 250 251 #endif /* BLK_INTERNAL_H */ 252